I meant to say pouch cells inherently have LESS sag then cylindrical due to their lower IR. The take away from this video shouldn’t be that 60V produce more torque or that their is a discernible range difference. We tried not to get deep into it because our explanation requires more than people would want to watch but this was our general point: A 60V battery allows you to hit equal levels of torque as a 72V at a lower speed which can be beneficial to those who ride off-road at lower speeds. Power can be broken down in two ways, in which the second was not brought up in this video. Electrically, Voltage*Amperage = Power. Mechanically, so does torque*RPM. If you set your power levels equal on two different voltages, one of which (the 72V) generates higher RPM, then the lower RPM voltage (60V) will need to create more torque to have equal levels of power. By going with a lower voltage you are basically shrinking the overall range of your powerband which means you get more torque over a tighter RPM range. We see this as beneficial to off-road riding. This has more of an effect once your further from the max PWM stage of phase amp generation where motor current ~= battery current. If you’re comparing equal torque (after the initial max): The 72V will be traveling faster which dramatically increases drag as the coefficient of drag function states it is proportional to velocity squared. Meaning that if you have to go faster to achieve equal levels of torque, you will actually have a decreased range not from a power increase but because of drag (depending on where you are in the efficiency curve). Drag from air at offroad speeds isn’t a massive factor but you have to consider that the same applies for rotational velocity in the drivetrain and the friction that comes from that. You can solve this by gearing down the 72V but the same could be said for the 60V especially if you’re not looking to go fast (we run the biggest commercially available sprocket, 64T, at 60V and can still hit 45-50mph). People who have been around the EBike industry a while do anecdotally notice they get a bit better range with lower voltages because it prevents them from riding as fast. Another interesting thing is that for ASI setups specifically, they function on a max nominal voltage of 72V. Not as relevant here, but usually as components approach their maximum voltage rating there is a decrease in efficiency on a very small scale that a 60V probably makes up for with more heat generation at equal power levels, not to mention 72V isn’t outside the operating range. Realistically the difference in range is almost entirely negligible and a range decrease from voltage increase is more notably because it’s easier to go faster and faster is more fun 🤘🏽
The best way is just to say how much more mph at top speed between the 2. How much more acceleration to certain speeds from a stop. Everything else doesn't matter much as we aren't calculating these things numbers wise, we are about the real-world feel and performance. As engineers, sure, all the numbers matter or else things could catch fire, blow up, or fail.
We would love to do that but collecting that some of that data isn’t super realistic. You’d really need a dyno for kind of information. For speed though that’s easy, motor rpm is linearly related to the voltage and kV value. So the speed would increase by a factor of 72/60. The acceleration thing depends on, weight, sprocket, traction conditions, rider positioning, etc. giving a definite number wouldn’t really be possible. Acceleration between the two should be similar but the 60V has a tight RPM band which suggests you may get off the line slightly quicker once motor current approaches battery current. We’d love to have the resources to accurately test all the things you’ve mentioned but it’s not in the cards right now.
My brains getting a voltage sage. What should someone consider when choosing between 60v and 72v? Body weight, terrain, air temperature, riding style, gearing, wheel size, tire circumference, tire tread, weight of bike...? What else...?
@@cvick44 I'm wondering the same also right now. I think the most important thing is if you want the higher top speed of the 72 volt. If you like to go 60MPH on your bike and do that often, then the 72 volt is better. If you ride at slower speeds off-road and never really go out on the street and do 60MPH often, then you may be better with the lower voltage as you will get better efficiency at those lower speeds. I think that is maybe how it works.
Great job explaining something that is insanely complex. I can tell a lot of work went into the structure of this video. Thanks for producing this one.
Great video, thanks for sharing. I have a question about battery impact on the motor, we know that above 13000W the motor starts heating a lot, is it better for the motor and would it be cooler if we choose 72V or even higher voltage with less amps than 60V/+amps in order to minimize motor heat ? In other words, are amps discharge the only factor for motor heat and is it better to go for more voltage to reach max power with less amps ?
@72vsurroni want to get a new battery for my surron but i dont know what to choose. Either 72v 32ah or 60v 56ah. Im looking for more speed since i only ride street. What do you suggest?
I deal with these kinds of numbers every day. You explained that perfectly 👍 but now you have me thinking maybe I should stick with the 60v setup because all I ride is hills off road. But every time I here these motor's spinning fast on a 72v setup It sounds amazing! 🤔
When you guys come visit with your battery I would love to film a real world test! Range is everything. Both have more power than I need in most instances but with any ebike setup I have used so far I could always use more range!
@@emotobros Almost everything makes perfect sense to me but I am still trying to grasp why the same amount of watts going to your motor but at higher amps generate more torque. I need the explain it to a baby version. Seems like it would be an epic video to do a run on your controller with a 60v than tune the same bike to a 72v and do the same run with the same rider. I am so down.
Basically physical equations state that the amount of torque in a motor is proportional to the flowing amperage times a constant. As amperage increases so does the magnetic flux that drives the motor therefor “creating” more torque. Not a very simple explanation but it’s not a very simple concept haha. Definitely excited to do a test🤘🏽
@@emotobros Thanks for that explanation. That gives me a lot of keywords to Google to truly try and grasp it haha and it definitely makes sense. The next generation of Dora the explorer type of content will probably be breaking down these types of equations as they will be a huge part of the average Consumers life. Think of right now how many people understand technical parts of petrol engines and their relation to fuel economy. When EV‘s are the norm the average person is going to have a pretty deep knowledge on the matter I think.
@@EdwinOlding One of the other nuanced aspects for better range could also be "C" rate. A 60v vs 72v (assuming equal KWH rating), the 60v will discharge at a lower C rate per cell due to the increased number of parallel strings. Also, all you guys need to come over to MT to ride some of the high alpine with us this summer when it gets hot down at the lower elevations.
Thankyou very much - I bought a compact VDM-10 eScooter with a Samsung 60v 21Ah battery feeding 2 x '1200w' motors! I found this magnificent video (with Chapters links in your Description) while looking for a 'call the Uber' lower voltage reading on the scooters volt meter. I also own the Samsung 18650 battery, and a range of other brands, sizes and types for my big collection of torches which I like to use and also test and compare with my lumen tube, commercial light meter, and battery charger. I reached an understanding milestone here today.
If you guys are making a battery for the surron, I would say few things I would want to see. 1. Very good cells for long range rides, and proper shelf life teaching for the viewers on how to hold the battery when not n use/ battery cells should easily be able to do 50,000 miles 2. Very high end BMS so there is 0% rate of anything ever going wrong! 3. Waterproof/ shock proof case, which can take thousands of miles of off-roading, jumps, (rock backs) from wheelie pops. My original 60v battery case is all scratched just from popping the bike hundreds of times. Someone like me will get on a bike and pop the bike into a wheelie 20 out of the 25mile ride I do. So this is important for the battery's inside to be able to withstand the most friction/movement/constant high power draw, then let off. 4. Go top tier or nothing when you make your battery. 5. Conclusion, SAFETY, QUALITY in cells, bms, build. Durability, and of course! Make the aesthetics a vibe on the battery have the case with a custom e-moto Bros logo. Then you guys will be set!
Those are all super good points. Manufacturability on cases right now is tricky when trying to figure out how to maximize capacity without sacrificing structure. We think we are doing a hard case wrapped in super tough but slick rubber so that when it gets beat up you can just cut off the putter rubber and put on a new one 🤘🏽. We will be using p42a cells with a 400A peak 180A cont. so we feel those are solid for reliability. Thanks for the advice!
@@emotobros Of course! That sounds legendary!! Stoked to see the designs for the cases, also maybe the outside rubber can have orange in some parts to make you guys stand out! That legit is a really amazing idea to have a replaceable rubber outer shell!!
And one more thing pouch sells dissipate heat through the positive and negative tabs very efficiently so you can have a fan on the top where they connect together to dissipate the heat
Only thing I would add is the amp hour ratings are based on a 20hr rate. The slower you discharge a battery the closer to the rating you get. If you discharge faster say one hour you don’t get the full amp hour rating.
@@emotobros I don’t know exact but the number in the solar battery videos I reference is 1+1=2.7. Because doubling the AH make overall discharge rate per cell or battery lower making it get more of its rated capacity
You'll find thats really only applicable (normal?) for lead acid batteries (or gel/AGMs)... most lithium based cells are rated on a 0.2-1C rate (20hr rate equates to a 0.05C rate) - the discharge efficiency of lithium cells is considerably higher, hence the 'faster' discharge rating. You'll get more range out of slowly discharging lithium too, but the contrast isn't as big (think 40+% capacity loss for lead acid at 1C, vs typically
Does bypassing the discharge side considered a negative than a positive in the battery world ? I’m noticing brands like chi batteries does this and I’m wondering if this is considered to be looked down on, I would assume you would need a bms on the discharge side to keep the battery cells healthy
Bypassing the discharge side is not ideal for a lot of reasons but the main one is safety. Companies do this so they can use a small BMS just to balance the cells while charging while not needing a massive discharge BMS to keep up with the claimed amp ratings which means more space for cells. This basically leaves you with a fully unprotected system which is fairly dangerous. The BMS plays an important role in disconnecting power from your system if things go wrong.
Thank you sir. I just bought a surron and I am a total lithium lamman (kinda like that super hero called ((handi man)) well any way I'm not here to notate my short comings rather I'm here to commend you for explaining something that until hearing your schpeal I figured that I'll use luck to keep my stock 60 v battery alive And now that I have a beginners understanding I'll never completely discharge my battery 🔋 🙃 but I am definitely going to have the (tim Allen surgery performed i.e. MORE POWER AR AR AR ON MY SURRON ) 72 V I NEED YOU. AS I AM A LARGE FELLOW AND I GOT A FEAVER. AND THE ONLY CURE ISNT MORE COW BELL BUT RATHER IS MORE POWER . THANKS AGAIN 😊
pouch batteries are usually LiPo batteries, found in cells phones and such. They light weight, can discharge very high power. The cost is however, its like the most dangerous battery in the world and will light you on fire, and much less cycle count. If you just want raw power and speed, at the cost of overall battery life, Lipo is the way to go. They can discharge 25c -40c+ compared to 18650s discharge rate of 2-5c. A 1000watt Lipo battery can discharge potentially 40,000watts, where a 18650 will max out say around 3000 watts. Big difference. Also between 60v and 72v, there is also another variable which is motor and wheel size. In fact, when it comes to efficiency and power, speed, I would say wheel size and motor are more important factors to look into. Basically fast spinning motor, and a fast spinning wheel. Faster spinning is better. Going from a 26inch mountain tire to a 17inch tire and upping the amps will make much more difference in overall speed, acceleration, efficiency than messing around with volts or amps. You'll look like a clown though with that tiny rear tire. Just another option to look at. RPMs is the key, electric motors love rpms. 10 years ago when ebikes were basically mickey moused garage projects, everyone was looking into upping the volts (and amps) to get more speed. Then this dude who knew what he was doing went another route, got a tiny ass rear tire, high wind hub motor (fast spinning/ really high kv).. and put tons of amps through it, and pretty much smashed all speed records. That's why u don't see 120v ebikes anymore. Also mid drive, like Sur Ron over any direct drive hub motors. Again because of RPMs.
I work for a battery distribution company I did a lot of research on pouch cells in particular the LG 20 amp hour they were took out of a group 48 lithium Porsche battery since working at this battery company called batteries Inc we've had a lot of people trying to dispose of lithium batteries one good thing to know about the Porsche is the lithium cells or not bad it's just a fuse or BMS issue so I have a great amount of these I decided to tear them apart and to salvage the cells little known about pouch cells is they can contain the same amount of pressure as a 18 650 when the 18 650 experience under pressure do not see it because of the casing when building a pouch cell battery they have to be packed in a type of way that holds them together they can withstand up 8 PSI before failing typically you want about PSI of pressure if you have ever took in a pouch sell that blowed it apart you can see how much pressure they can my point being if you have a naked pouch cell yes they will blow up over hilo's and charging when it's cold the 18 650 can also bloat but you don't see it but you can detect it by the amp our loss
House shows or a lower voltage sell than 18 650 at 3.2 volts+ 3.4 in the higher range a pouch cell has the same performance from 3.2 volts to about 2.8 v
i want to get a new battery for my surron but i dont know what to choose. Either 72v 32ah or 60v 56ah. Im looking for more speed since i only ride street. What do you suggest?
72V will give you a higher top speed. I recommend getting a battery with a BMS that has a pre-charge functionality and is not bypassed. Chi batteries for example uses a small bypassed BMS only far charging and has no discharge protections, which we would not recommend.
Glad to see there are smart and well spoken people out there. Very well done, and great information given. Can I ask why something like heat pipes hasn't been done on something like this yet? There would be enough space between cells to use them and I'm sure some surface area added for heat transfer has to be better than none. With an aluminum case as a heat sync as a free place to dump more heat I can see it being a logistically simple solution.
@@emotobros I can understand those points for sure. Can I make a video request? Maybe an explanation on all of the controllers including the stock ones. Specs, limitations, tunable points. Hacks and mods, maybe an explanation as to what Luna did to make the xx controller what it is. Just a full run down on all the possible controllers in one place would be awesome.
Pouch cells it had bloated out the sides of the case a little bit when I cut the sides off the cells expanded 3 2 5 x its original size with crazy amount of force they're about the same if contained properly in a battery casing
Very good...Ive been building battery packs for 7 years, I think you covered most of it, however I still have a question that I havent seen answered yet..as I am waiting for my Sur-ron, and am going to either build an extender 60 volt battery for increased range AND, because im joining more cells in parallel (11 stock plus 10 in my build) thats 21 cells in parallel and if I pull the same amps (80 lets say) then the stress and hence voltage sag will be minimal and less than the stock pack. 80/21=3.8 amps per cell. If I increase the amps to 110 for example (that would be 40% increase in torque) each cell is still only seeing 5.2 amps per cell and voltage sag would still be minimal. Here's the question: Cannot the stock x controller handle 72 volts? (84 volts full charge and 74 volts nominal). I see people using the BAC 4000 controller and bypassing the BMS on the LOAD side, which in my opinion is a bad idea...get carried away on your fun ride while the pack is at 54 volts and suddenly you start dipping into 48 volt range and cells that are unbalanced and lets say .2 volts lower than average in the pack get dangerously close to going below 2.5 volts, because without the BMS, you have no way of knowing what the individual series of cells are at any state. I would consider replacing the stock BMS with one of mine that can handle 100 amps now your covered, but still would like to know why or if the stock controller can handle a 72 volt pack.
Great question. I’m under the impression the stock controller cannot handle 72V… but never thought to try it. I assume the controller must be reconfigured to do it. I know my bac4000 has the two settings and you must set it to the correct voltage
Great video on tork vs speed with A vs V and general info on lithium-ion batteries 😊 where could I get more info and source parts with building my own 60v Surron batteries out of cells out of a Tesla module? Case, BMS etc
Thanks! Since the market is relatively ‘new’ there aren’t a ton of well done videos on the subject but search on UA-cam how to build a ebike lithium battery and you’ll find some useful info. Most all supplies are sourced from China.
Ok I have a noob question and would really appreciate your feedback. I have a stock Segway x260 and all I am looking for is extended range as the speed is perfect for the off road trails I ride. I just purchased the Lite Speed 60v50ah Surron Long Range battery. According to the description, I will not have to switch out my stock controller and it will take me from the stock 32ah battery to 50ah for more range. Did I make a good purchase based on my goal of extended range without changing or “pushing” the motor / controller? Your feedback is appreciated
Thanks for the quick reply. I asked because I have seen zero videos on this particular battery and thought it would be a popular choice and was a bit worried that their are zero reviews. Thanks
Yes something we totally forgot to mention. Many people will go 72V and then run a taller gear in the rear to turn some of that extra speed into more torque.
I watched the whole thing again. I'm fairly familiar with battery chemistry after following Tesla and Jeff Dahn for years. Your explanation is very good, as usual:)
Excellent explanation!!At 66 I thought I couldn't fit any more into this overloaded brain.Guess I was wrong again!Xr600 used less,Sur Ron used more.One question.Can a 48 volt Sur Ron battery be built to 60 volts by adding more batteries?Can Bms be utilized for such or would it have to be changed?Thanks for your excellent video!
So I've got a 72volt lipo in my razor... it charges to 87.7volts... if I buy a segway x160 I could probably use my same lipo I have now with a proper controller and itd be a dope surron yes???
@@emotobros its gotta have a stronger motor than the 3000watt mid drive motor I've got pushing 7000watts from... and itll be so much prettier lol thanks
@@emotobros I don't think there's such thing as a used surron.. and if there is itll be more than a stock one prob with upgrades... kind of my only option. I been clean for a little over a year and I'm hooked on these things. But can't really afford nice things although I'm trying for sure..
this video is good and accurate though there is an exception to everything said here and an argument could be made to suggest errors but this is very accurate but you start getting into batteries made graphine or graphide and or with cooling systems or BMS systems that governed to prevent max or minimum charges can have a world of difference in capacitance or discharge. like some people max charge and max discharge their phones or bikes or cars you name it this can cause severe battery degradation and a degraded battery get more dangerous the more it is abused by lower quality BMS. a good quality BMS will deliver more poor performance as it degrades providing longer life or a poor BMS will rock hard till you get that nasty smell and then brick. i try to avoid letting any and all batteries from having a full cycle buy discharging no less than 20% and stop charging at 80%..... this will give you max battery life but this remove 40% or your range!!!! so in my 320 mile rated tesla i really only get less than 200 miles per charge. hence why im thinking to buy a second battery for my new bike. you often get about 5000 cycles aka charges per 18650 cells. long as you stay with in battery tolerance being about 8% min and 91% if you abuse your battery to discharge lower and charge higher you will get less cycles if you stay between 20 and 80% you are doing micro cycles possibly doubling how many charges you get from battery. problem is you rarely get much peak performance with an 80% battery and voltage drop occurs about 70% so with a good BMS you should see a decline in output the lower the battery gets but a bad BMS could over draw =heat =death of cell 1st problem with electric limited range 2nd performance fall off 3rd down times of charging!!! but that torque nearly makes up for all the flaws
always go for higher rpm and higher gear reduction for torque, an electric motor has the highest efficiency at higher rpm. I would always go for 72V or even higher and use a bigger sprocket for more torque. You can get the same torque as a 60V System at the same power level, but with more efficiency as the datasheet of surron motors shows.
I'm looking to get more power but not crazy power (7000-9000W) but also a little more range than stock. Is there a battery and controller that would do this? Maybe a 52AH and a BAC4000? Could i then also use my old stock battery as well?
There is little-to-no information about pouch cells unless you read through a bunch of boring chemistry books if you want to hear more about properly making a pouch cell battery let me know in the comments
If you program the controller for Lightspeed 72v I assume I can still use the stock 60v battery for dinking around the on property or while the 72v battery charges? Switch to a lower setting?
Nope, not how that works. Once the system voltage is set at 72V you need to be using only 72V batteries. If you would like to utilize your stock battery you should purchase an upgraded 60V battery.
In the future will the bac4000 have an option to easily switch between 60v and 72v? Alot of Chinese controllers handle any thing from 40-100v. Just curious if this could be an possibility. Btw are the bac4000 going to be in stock soon?
arf j'aurais tant aimé voir cette vidéo en français! Quelqu'un pourrait il m'indiquer si il existe un moyen de traduire cette video, sans trop de perte de temps?
SORRY THIS IS A REPOSTED QUESTION BECAUSE THE VIDEO I ORIGINALLY POSTED TO , I REALIZED IT WAS A LOT OLDER.... Hey buddy.... I'm new to your channel and just subscribed. I would like to see if you or your subscribers can offer me your opinion on a sur ron. I know there's the x-controller and 2 others like the 400 or 800 bac controllers, plus a few battery upgrades from larger 60v to different size 72v. So....... I'm a 250LB man and what I'm looking for out of this setup is 50mph with the longest range possible hopefully getting 40 miles riding 35-50 mph and 85% of the time on the streets. ANY AND ALL OPIONS WOULD BE GREATLY APPRECIATED. thanks!!!
This set up would be the most efficient for what you’re trying to do. I have a 72v 40ah battery with a ASI BAC8000 controller. I’m doing 13.5kw max and I’m a 170lb rider I get a range of about 30 to 40 miles of range going at speeds of 45-55mph. I get 20-25 miles going at speeds 55 to 65mph. Just know that this set up is very expensive and I highly recommend you upgrade your suspension, tires, and brakes. Please be safe and I hope this helps.
@@stevennguyen8250 hey.... thanks for the help and input.... about your 72v 40ah battery.... is that made with 18650 batteries 21700 batteries or ive seen them recently made with a type of bag or pouch batteries. Is that from litespeed if not where do you recommend shopping for a battery...... THANKS AGAIN..... and yea its expensive but you get what you pay for... I've always believed...... buy once cry once.... meaning it will hurt to spend xtra to get quality but it should last MUCH LONGER THAN BUYING CHEAP
I highly recommend Litespeed that is where I got my battery from and my battery pack is made from 21700 cells. Talk to Chris and tell him I sent you he’s very reliable and good at his job. If you’re going to upgrade your battery and controller please get a better wheel build and upgraded brakes. Just make sure you balance your tires you will experience speed wobbles at 60mph and above.
@@stevennguyen8250 yea its alot of cash... I just bought a 3,000 dollar kaabo wolf warrior 11 electric scooter and dropped another 1,000+ on xtras but realized I'd rather a bike to sit when I'm using it as transportation so my plan is to drop the 4,000 on a sur ron and slowly drop a 1,000 give or take on brakes,tires,forks, then ride stock battery/controller for a month or 2,and then ill drop the 3,000.....lol.....GIVE OR TAKE on the 72v battery and the controller 8000...... its gonna be a hard 8,000 dollars but I THINK EVEN AT 250LBS IT WILL BE VERY WORTH IT! AGAIN THANK YOU FOR YOUR HELP!!!!!
Sorry mate but so much in this is so far off the mark that its hard to know where to start... I know you mean well and all but your attempt at simplifying it necessitates at least understanding the fundamentals of how motors (particularly BLDC and similar) produce torque, and how it relates to battery voltage/power... just saying 'this is nuanced' all the time doesn't actually mean you understand it or are simplifying it... For instance: /Torque is determined by phase amps... not battery amps. The 60 vs 72V version you give at around 12:30 is flat out wrong... both systems will produce the same torque at the same rpm, despite the difference in voltage... because its battery POWER that determines torque, as that is what produces phase amps in the motor. /Phase amps at a given RPM require a given amount of power from the battery. Doesn't really mater if its 72 or 60v... it needs x power for x torque at x rpm. So you have to draw more current from the 60V battery to produce the same torque at a given rpm. /Double the rpm, you need double the power for the same torque /double the torque, you need double the power for the same rpm /double both, you need 4x the power for 2x the torque and power. / ergo, a 60v battery is not more efficient than a 72v at a given torque level. on the contrary, unless its a more efficient (larger capacity and/or lower IR cells, thicker battery cables etc) pack its probably less efficient, and certainly the wires from the battery to the controller will be more lossy too (read, more voltage sag). On some other points: /Pouch cells are not inherently lower cycle life, or more saggy. On the contrary, they're generally less saggy due to better internal connections to the 'outside' (lower internal resistance) - there's a reason the new tesla cylinder cell is so much higher power, and its a lot to do with brining pouch cell advantages to a cylinder cell... and chemistry has far, far more to do with cycle life than does pouch vs cylinder. cycle life of either type can be in the 1000's or in the 10's. / the packing density you talk about is simply wrong. if you want proof- calculate the surface area of a single 100mm dia circle, then the surface area of 4 x 50mm dia circles. Clue... they're the same, and both will fit in the same square box, and thus, so is the energy density of cylindrical cells in a given volume. you may be able to fit more smaller cells in a pre-determined size of casing, but unless thats constrained to a non-interger multiple of the large cell, then its not a factor at all. / there's more mate, but honestly your selling this shit and speaking as a source of knowledge, clearly without the knowledge to do so. While there's nothing in this vid thats likely to get people hurt, this attitude that runs through a lot of the posts you make on FB or on YT will eventually cause someone to make a mistake that could have been prevented by you simply putting in the time to gain the expertise you need to speak on these subjects (as ive seen happen with some of the kits you've sold). I'm always hesitant to be too harsh, but this is not the first time you've done this mate. Take it from a guy who does know... you dont know enough (yet) to be publishing guides or info on these subjects, targeting the 'everyday joe' or otherwise. While I welcome more people onto the EV grin bandwagon, publishing misleading bollocks is only going to get our hobby more overregulated by overzealous gov's than it already is. There's been calls in the past to ban cell sales to end users, and this is only going to add fuel to that fire, figuratively and literally.
Hey thanks for the comment and I'll address these one at a time. To begin with, torque is not determined by phase current outright. Of course battery current isn’t what is going directly into the motor so that’s taken a bit out of context with you insinuating/thinking that’s what I meant, but really where the current is coming from isn’t exactly relevant to the argument. Torque is a response to a load, not the other way around. An increased load creates an increase in drawn current from the battery. If you were on a slope of 1 degree, the torque needed to overcome the force of gravity pulling you down the slope would be minimal and the current draw would reflect that. If you were to increase the slope to 45 degrees, you’d need a lot more torque to keep the bike from being pulled down the slope by gravity which would require a much greater draw of current than the 1 degree slope regardless of voltage. My argument was never that unfiltered DC current was what was being put into the motor. I’m aware that the controller controls power levels to the motor using pulse width modulation; however, it didn’t seem relevant to the argument since all that does is complicate things unnecessarily. The bottom line is that an increased load needs increased torque- which requires a higher current draw to overcome. Equal levels of phase current while drastically varying the input DC current will not produce an equal amount of torque. It is more the time derivative of torque that is determined by phase current (the parameter itself not the actual current). Technically speaking, torque at an RPM is based on phase current so in a sense it determines the torque, but that's somewhat of an oversimplification considering an increase in phase current doesn't pull more DC current from the battery at the peak, and peak times from low to high phase amps are shifted, but in our case, not by more than a few seconds. Anecdotally, the phase current parameter has more to do with power ramping from a stop, and twitchiness of the throttle when considering its effect on the Sur Ron. This has been plotted in great detail on our instagram. For the difference in battery voltage vs. efficiency. Torque can also be said to come from power since voltage can be considered constant and as we mention increased current increases the torque. Therefore an increase in power (from voltage) SHOULD lead to a proportional increase in torque. However, this is only for the 100% efficiency case which I mention. I clearly state that the increase in power (from higher voltage) will result in the increase of torque but not at the same ratio as the power is increased at. What happens mathematically is not necessarily what it will do under real conditions especially considering that all mathematical models are an approximation. Addressing our claim that a 60V battery has more torque at the same power levels than a 72V battery: This is not a new or controversial statement. A 60V needs to have a higher current than the 72V to reach equivalent power. This is far more relevant to stall torque (and overcoming it) than it is under average riding conditions. You're right about the sag from a technical standpoint although there isn’t a lot of literature on the topic. “Inherently” was definitely not the correct word to use and pouches do in fact have a lower IR which would inherently lead to LESS sag, I see that error. I should've been more clear that the increase in sag from pouch cells have been directly noted from testing pouch cells batteries for the SurRon vs cylindrical cells. Certainly not always the case but it was for the ones we've observed/tested, and what is relevant for the video. I would say this is generally due to a lower output rating of pouches in comparison to cylindrical cells where the BMS/Motor is the limiting factor. Under low draw conditions pouches may have a higher cycle life and less sag but under high draw conditions, which the SurRon produces, it seems to lead to a lower cycle life and more importantly swelling. Regarding the cell packing. It seems unfair to say "unless that's constrained to a non-integer multiple of the large cell", because it is. This is going into a SurRon that has a very specific battery compartment size which can't be changed just to optimize the fitment of larger cells. Smaller cells give more freedom in POTENTIALLY increasing the energy density. I should've been more specific about that but again this is for the SurRon not in general. You're are correct that if that box size is an integer multiple of BOTH cells that it'd be equal in capacity. The tradeoff being that the smaller cells will build heat quicker due to smaller air gaps. The main takeaway was supposed to be that the larger cells give less freedom for battery sizes and beyond that these cells only seem to be getting bigger (ex. The new 4680 at more than double the diameter). Saying we are ‘so far off the mark’ seems like a stretch. Basically every point you addressed is far less useful to the average joe (our audience) than the simple power calculations and general information that we gave. Going as far as saying videos like this are the reason for more laws being created...seriously? Even if someone who had the power to create these laws did watch this video, I highly doubt that’s what would be taken away from this video and at the end of the day being ‘technically’ wrong about phase amperage, cell packing and pack voltage vs. efficiency certainly is no reason to create laws. We actually aren't selling anything related to the video so I'm not sure what you mean in that regard and you're only gripes seem to be highly specific and nuanced in their own right. We are always open to expanding our own knowledge, and do not shy away from correcting ourselves when we are wrong. That being said, we hope you understand that we do understand these things quite well and will occasionally simplify things for the audience. We do not feel this diminishes our credibility or our ability to educate people on the subject. We have done a lot of research on these subjects as well as completed college level courses on the fundamentals of these subjects as well. While we may not be leading experts in the field, but we are trying the best we can.
@@emotobros @E-Moto Bros I appriciate the tone of the response, but mate, your still missing some major points here... I'll start with one of the more significant since it highlights the problems you're repeating. "Addressing our claim that a 60V battery has more torque at the same power levels than a 72V battery: This is not a new or controversial statement. " Oh, but it really really is. put simply, thermodynamics. Unless the efficiency of the system is somehow dramatically more efficient at 60v, then this is physically impossible - and I'll tell you for free the efficiency doesn't change significantly. This statement is simply flat out wrong. Power output is a linear function of torque and rpm... so if you get more torque out, then your outputting more power. You cant get more torque out of a system 'at the same power levels'... it just aint possible. "Torque is a response to a load, not the other way around. An increased load creates an increase in drawn current from the battery" No. This was 'kind of' the case with old style PWM controllers/brushed motors (though not really) but not at all for modern torque based systems, like the BAC. The controller has direct control over the phase currents, and as such direct control over the torque. The only time it cant produce that torque is once back EMF is high enough to limit the phase currents rather than any pwm'ing... the load only factors on how quickly the motor/wheel responds to that torque (ie accelerates). Again... its the phase current that determines torque - it will do so no matter what the load. Increasing torque does not require increased load, it requires the controller to push more current into the motor. 1. motor rotor is in position x 2. controller applies phase currents at 90deg to this 3. interaction between stator electro magnets and rotor magnets produces a turning force on the shaft 4. motor turns, if it is able/torque is sufficient to overcome any loads being applied. 5. repeat from step 1. If it was only a response to load then the acceleration of the wheel would be a constant for all loads, up to the max torque. "The bottom line is that an increased load needs increased torque- which requires a higher current draw to overcome" Not when comparing 2 different voltage batteries. The higher voltage battery will draw less current to produce the same torque, in direct opposition to your claims in this vid. "Equal levels of phase current while drastically varying the input DC current will not produce an equal amount of torque." Yes it will. Phase current determines torque. The input current, as it pertains to torque, is irrelevant. 100V 10A draw or 10V 100A draw form the battery - if there's 150phA in the motor, then the torque on the shaft will be the same. go back to basics. There's a certain turn count in the motor, of copper, around each tooth. And a certain current in those turns... a certain number of amp turns... These amp turns are directly driving the flux in the air gap, and as a result of the interaction with the rotor magnets, the forces on the shaft (namely, torque). Try to think of it from teh motors perspective. It never 'sees' the battery voltage - you can confirm this yourself with a multimeter between any 2 phases... it will be < the battery voltage (at least for lower rpms), yet torque can vary wildly all the same. If the battery voltage never appears at the motor windings, yet the torque can vary between 0 and 100% of what's possible, how is it that battery voltage can possibly be influencing the motors torque? The answer is that it isn't. "but that's somewhat of an oversimplification considering an increase in phase current doesn't pull more DC current from the battery at the peak," Yes, it does increase current draw from the pack. It has to - because increasing torque at any given rpm will increase the power output of the motor... so unless you've increased the efficiency of the motor+controller somehow (see first comment re thermodynamics), there's simply no way to increase torque without a corresponding increase in power draw. Its not even a matter of motor knowledge at this point... its basic thermodynamics. torque x rpm = power output (must be less than) power input = battery voltage x battery current. you cant get more power out without more power in... "Anecdotally, the phase current parameter has more to do with power ramping from a stop, and twitchiness of the throttle when considering its effect on the Sur Ron'' And this may give a clue to the problem... how it feels is not how it 'is'. that snappiness is the faster ramp up of phase current over the same throttle movement... ie... more torque for the same throttle input. And again, if power input is ramping faster... then (almost by definition) so is power output... because more torque at the same rpm = more power output...
"I clearly state that the increase in power (from higher voltage) will result in the increase of torque but not at the same ratio as the power is increased at." This is the same regardless of voltage, more power draw = more torque. increase torque by 20%, you'll need to increase power by at least that amount ... whether its a 50v or 100v battery. If anything, the lower voltage battery will be less efficient, due to higher losses over the same size cables between the battery and the controller. yes, you do get higher switching losses at a lower duty cycle, but this is marginal enough to be irrelevant. "You're right about the sag from a technical standpoint although there isn’t a lot of literature on the topic. " There's literally tones of it. perhaps not directly related to the surron, but then it doesn't need to be. "and pouches do in fact have a lower IR which would inherently lead to LESS sag, I see that error." No your jumping too far the other way. Pouches CAN, but its not a rule. I know I'm somewhat focusing on semantics here but the point is that cell config (pouch vs cylinder) doesn't directly impact performance, certainly not relative to all the other factors/enough to generalise either way. "... less sag but under high draw conditions, which the SurRon produces, it seems to lead to a lower cycle life and more importantly swelling." again, purely anecdotal. You can find any number of cells of either configuration that will perform well, or terribly. The pouch vs cylinder is completely irrelevant next to chemistry choice, internal architecture etc etc - this is my point here. "This is going into a SurRon that has a very specific battery compartment size which can't be changed just to optimize the fitment of larger cells." Fair enough if talking specifically on the surron, sorry it came across (particularly after the pouch cells points) as a general remark. though by the same token, the two common form factors (21 and 18) fit the surron well... "Going as far as saying videos like this are the reason for more laws being created...seriously? " I certainly dont think this vid itself will lead to more regulation. What I do see happening though is more and more people getting into this hobby, watching a few vids on the subject, and 'burning their house down' as a result. Part of what will cause more accidents is incorrect information, and poorly designed equipment being given to laymen's to install... as I have seen happen with your guys stuff once already, where a combination of poor choices of hardware, and poor instruction (not just from you, to be fair) has already lead to one of your customers getting a major fire.... "That being said, we hope you understand that we do understand these things quite well " I do appreciate the openness and am all for people sharing their knowledge. But as mentioned above, there's some simple, fundamental things your getting wrong that will only serve to further confuse people on this subject, yourself included. There's simple and easy ways to explain it without breaking fundamental laws of physics - and its a dangerous situation when you make this kind of claim when you clearly dont... if you understood these things well, then you wouldn't be saying / doing / selling the things you are, and touting yourself as a point of information is only going to cause others to follow you on that path... "We actually aren't selling anything related to the video so I'm not sure what you mean in that regard" your claiming to be a source of knowledge/expertise on the subject, yet you're making mistakes again here, that are similar in nature to mistakes made previously with what you do sell. Like I said above, I dont think this vid itself is posing any major risk per se, but your body of work can (and has) and this vid is reminiscent of the mistakes you keep making, and not correcting. " as well as completed college level courses on the fundamentals of these subjects as well." And your talking to a specialist who works with motors measured in the mega watts, with torque outputs literally, not figuratively ... in the region of 10,000 times higher than the surron motor, and been building + modding emotos/ebikes for ~ 10 years... Oh, and ive 'completed collage level courses' too. That said, ive also known 'experts' and guys with masters/doctorate degrees that couldn't handle the most fundamental basics, and guys with no degrees at all who could make me look like a fool. So if an argument from authority is 'valid' then I think I safely 'out authority' you... else arguments form authority don't prove anything, in which case, dont play that card. Point being, its not a strong argument to make an argument from authority. The fact that you or I have x experience or knowledge doesn't make a wrong answer right. I mean this honestly, I wish you guys the best and im all for more people contributing - but im not sure your really living the 'do not shy away from correcting ourselves when we are wrong' mantra. When things have gone wrong in the past you've been quite insistent that it was not your fault, or the fault of your kit, but the fault of other elements of the install - when the simple fact is that multiple elements contributed to the fire, including your own workmanship/kits/advice. Now here you are breaking the laws of thermodynamics to prove your point, rather than take a moment to check what your claiming is even possible.
@@sn0wchyld Reading and writing replies in this thread is becoming quite laborious so I figure we will just link exactly where our information is coming from and you can feel free to list discrepancies you have with it: Everything we've said is coming from this very accurate motor simulation model: ebikes.ca/tools/simulator.html?motor=ST-HM-03&batt=cust_60_0.2_52&wheel=19i&mass=50&hp=0&mid=true&gear=1.5&tf=30&tr=11&cont=cust_330_430_0.03_V&eff=94.1&axis=mph&cont_b=cust_330_430_0.03_V&motor_b=ST-HM-03&batt_b=cust_72_0.2_42.5&wheel_b=19i&mass_b=50&hp_b=0&tf_b=30&tr_b=11&mid_b=true&eff_b=94.1&gear_b=1.5&bopen=true Every parameter simulated between the two tests are literally exactly the same (including the battery cell count) with the only difference being the input voltage. As you can see: -If you set the torque of each system equal to each other with the sliders the RPM of the 72V system is higher (as we suggested), the power draw of the 72V system is higher (as we suggested) and the motor current/battery current are within 2% of each other (as we suggested). This is how we came to the conclusion that the same amperage levels give the same torque despite the 72V using more power, therefor it is less efficient and will reduce range at equal levels of torque. You also said that at the same RPM the torque levels are equal; we are also not seeing how this is possible based on these simulations (All comparison were done pre-peak power or post-peak power so that we weren't straddling the dome). We do notice that the efficiency of the 72V system is a bit higher in the motor but a 3% difference isn't making up the multi-100Watt difference in power draw that the 72V is using at the same torque. Now it is entirely possible that we completed are misinterpreting the data, but I don't think laws of thermo. are being broken in this simulation and it is also a lot more advanced than a basic linear model without efficiencies. If you could please post something that proves how we are misinterpreting the data or how the model itself is wrong that would be much appreciated because clearly we are missing something as you seem highly confident that we are wrong.
@@emotobros I had half thought to write a reply pointing out each place where you're missing / misinterpreting something but I'll try to keep it short and sweet and focus on just 1 or 2 points: "Now it is entirely possible that we completed are misinterpreting the data" This is the issue here... let me explain: "This is how we came to the conclusion that the same amperage levels give the same torque despite the 72V using more power" It uses more power because your going FASTER... More fast needs more gogo juice... ffs dude, look at your 'load' value... its higher in your example on the 72v system so of course it needs to draw more power. "but a 3% difference isn't making up the multi-100Watt difference in power draw that the 72V is using at the same torque." And you state that you understand the relationship between torque and power - indeed, its in the blurb 'how to use the simulator' on that very link you provided... yet somehow you say that 2 systems of near equal torque outputs have vastly different power requirements? Why do you think this might be the case? Again, look at the load your 2 systems are under, and the speed they are going. " therefor it is less efficient and will reduce range at equal levels of torque" Mate.... the very thing you just sent TELLS YOU the system efficiency - its the litte green numbers under the graph next to the term 'efficiency'. And the system efficency of the 72V system is HIGHER in the situation you describe (This is my point re 'misinterpreting'... The very thing you're using to prove your point emphatically refutes it....). Part of the issue here is your using an ASI motor... this is not the surron motor with your ASI controller parameters, so you're not going to get a acurate picture about what happens on this bike. You've also set your battery perameters at the same IR... which is unlikely to be true, and 0.2ohms is pretty high too, hence why your battery is sagging so much. These 2 factors are why its never drawing anything like 330A, or putting out 430phA. Your never seeing the phase limit on your controller, hence why the graph you have here has no continuous torque section at all... ebikes.ca/tools/simulator.html?bopen=true&batt=cust_60_0.2_8&batt_b=cust_72_0.24_6.66 This is a more representative example of whats happening on the surron between the two batteries. I've equalised the power capabilities of the 2 batteries (proportional IR and capacity). at high loads and low rpms (where the blue torque curve is flat) both systems produce the same torque, because the controller is at its max phA limit (in this case, ~40A, but the same would happen for the surron motor if you input it with your controller). As you can see, the higher voltage battery has the exact same efficiency curve, to the point where the power limited zone of the 60V battery is reached. The 72V system is less efficient from this point on... but this is because its producing more torque at that rpm... by being able to push more phase amps at that rpm.
"as you seem highly confident that we are wrong." Mate, you are... Your telling me that the 72v system is less efficient by linking a simulator that shows its more efficient... I'm not sure how else to explain it. it doesn't even require interpretation of the results, you can just read the data right off the table, or the graph. As to your earlier comment, ill just grab one section: "If two college aged adults who have only been in this industry for 6 months is your only source of information, especially after informing people in the first 45 seconds that we will be wrong about things, then I'm not sure what to do about that but we aren't going to shut down our channel and business because we've said something that wasn't correct." dont be rediculous. I've said repeatedly that im all for you guys doing what your doing... but there's some stuff your getting wrong, quite wrong and some of it poses a danger, particularly when you guys are building a resonable following. The tone of some of my responses might be a bit 'harsh' but its due to your defenciveness on a few points here and prior, and your continued insistance that 'we know what we're doing' despite all the evidence to the contrary... see above RE your claims on 'efficiency'. And if your confidence in your abilities is so low, why are you calling this the 'ultimate' guide to anything? There's plenty more I can say but in the interests of keeping things (relatively) short... ill leave it focused on just this. Happy to explain further if you need.
this sums up about a months work of my own surron researching in about 10 mins
Same lmao are you also building your own battery?
I meant to say pouch cells inherently have LESS sag then cylindrical due to their lower IR.
The take away from this video shouldn’t be that 60V produce more torque or that their is a discernible range difference. We tried not to get deep into it because our explanation requires more than people would want to watch but this was our general point:
A 60V battery allows you to hit equal levels of torque as a 72V at a lower speed which can be beneficial to those who ride off-road at lower speeds.
Power can be broken down in two ways, in which the second was not brought up in this video. Electrically, Voltage*Amperage = Power. Mechanically, so does torque*RPM. If you set your power levels equal on two different voltages, one of which (the 72V) generates higher RPM, then the lower RPM voltage (60V) will need to create more torque to have equal levels of power. By going with a lower voltage you are basically shrinking the overall range of your powerband which means you get more torque over a tighter RPM range. We see this as beneficial to off-road riding. This has more of an effect once your further from the max PWM stage of phase amp generation where motor current ~= battery current.
If you’re comparing equal torque (after the initial max): The 72V will be traveling faster which dramatically increases drag as the coefficient of drag function states it is proportional to velocity squared. Meaning that if you have to go faster to achieve equal levels of torque, you will actually have a decreased range not from a power increase but because of drag (depending on where you are in the efficiency curve). Drag from air at offroad speeds isn’t a massive factor but you have to consider that the same applies for rotational velocity in the drivetrain and the friction that comes from that. You can solve this by gearing down the 72V but the same could be said for the 60V especially if you’re not looking to go fast (we run the biggest commercially available sprocket, 64T, at 60V and can still hit 45-50mph). People who have been around the EBike industry a while do anecdotally notice they get a bit better range with lower voltages because it prevents them from riding as fast.
Another interesting thing is that for ASI setups specifically, they function on a max nominal voltage of 72V. Not as relevant here, but usually as components approach their maximum voltage rating there is a decrease in efficiency on a very small scale that a 60V probably makes up for with more heat generation at equal power levels, not to mention 72V isn’t outside the operating range.
Realistically the difference in range is almost entirely negligible and a range decrease from voltage increase is more notably because it’s easier to go faster and faster is more fun 🤘🏽
The best way is just to say how much more mph at top speed between the 2. How much more acceleration to certain speeds from a stop. Everything else doesn't matter much as we aren't calculating these things numbers wise, we are about the real-world feel and performance. As engineers, sure, all the numbers matter or else things could catch fire, blow up, or fail.
We would love to do that but collecting that some of that data isn’t super realistic. You’d really need a dyno for kind of information. For speed though that’s easy, motor rpm is linearly related to the voltage and kV value. So the speed would increase by a factor of 72/60.
The acceleration thing depends on, weight, sprocket, traction conditions, rider positioning, etc. giving a definite number wouldn’t really be possible. Acceleration between the two should be similar but the 60V has a tight RPM band which suggests you may get off the line slightly quicker once motor current approaches battery current.
We’d love to have the resources to accurately test all the things you’ve mentioned but it’s not in the cards right now.
My brains getting a voltage sage. What should someone consider when choosing between 60v and 72v? Body weight, terrain, air temperature, riding style, gearing, wheel size, tire circumference, tire tread, weight of bike...? What else...?
@@cvick44 I'm wondering the same also right now. I think the most important thing is if you want the higher top speed of the 72 volt. If you like to go 60MPH on your bike and do that often, then the 72 volt is better.
If you ride at slower speeds off-road and never really go out on the street and do 60MPH often, then you may be better with the lower voltage as you will get better efficiency at those lower speeds.
I think that is maybe how it works.
@@Fighter4Street 😂 that’s what I’m thinking…
Great job explaining something that is insanely complex. I can tell a lot of work went into the structure of this video. Thanks for producing this one.
It’s like learning a new language! Thanks for breaking it down for us.
Thanks for putting all this information together in one breakdown!
You guys are AWESOME at explaining things so everyone can understand. Been at this for awhile and still learning........Thank you for posting!
Even though I didn't understand everything, I know more now than I did before. Thanks for dropping the knowledge!
Great video, thanks for sharing. I have a question about battery impact on the motor, we know that above 13000W the motor starts heating a lot, is it better for the motor and would it be cooler if we choose 72V or even higher voltage with less amps than 60V/+amps in order to minimize motor heat ? In other words, are amps discharge the only factor for motor heat and is it better to go for more voltage to reach max power with less amps ?
@72vsurroni want to get a new battery for my surron but i dont know what to choose. Either 72v 32ah or 60v 56ah. Im looking for more speed since i only ride street. What do you suggest?
I deal with these kinds of numbers every day. You explained that perfectly
👍 but now you have me thinking maybe I should stick with the 60v setup because all I ride is hills off road. But every time I here these motor's spinning fast on a 72v setup It sounds amazing! 🤔
That 72V whine is pretty awesome
When you guys come visit with your battery I would love to film a real world test! Range is everything. Both have more power than I need in most instances but with any ebike setup I have used so far I could always use more range!
We’d be curious as well! Mathematically it makes sense but end of the day if it doesn’t work in practice than it’s not super useful 🤘🏽
@@emotobros Almost everything makes perfect sense to me but I am still trying to grasp why the same amount of watts going to your motor but at higher amps generate more torque. I need the explain it to a baby version.
Seems like it would be an epic video to do a run on your controller with a 60v than tune the same bike to a 72v and do the same run with the same rider. I am so down.
Basically physical equations state that the amount of torque in a motor is proportional to the flowing amperage times a constant. As amperage increases so does the magnetic flux that drives the motor therefor “creating” more torque. Not a very simple explanation but it’s not a very simple concept haha.
Definitely excited to do a test🤘🏽
@@emotobros Thanks for that explanation. That gives me a lot of keywords to Google to truly try and grasp it haha and it definitely makes sense. The next generation of Dora the explorer type of content will probably be breaking down these types of equations as they will be a huge part of the average Consumers life.
Think of right now how many people understand technical parts of petrol engines and their relation to fuel economy. When EV‘s are the norm the average person is going to have a pretty deep knowledge on the matter I think.
@@EdwinOlding One of the other nuanced aspects for better range could also be "C" rate. A 60v vs 72v (assuming equal KWH rating), the 60v will discharge at a lower C rate per cell due to the increased number of parallel strings.
Also, all you guys need to come over to MT to ride some of the high alpine with us this summer when it gets hot down at the lower elevations.
Thankyou very much - I bought a compact VDM-10 eScooter with a Samsung 60v 21Ah battery feeding 2 x '1200w' motors! I found this magnificent video (with Chapters links in your Description) while looking for a 'call the Uber' lower voltage reading on the scooters volt meter. I also own the Samsung 18650 battery, and a range of other brands, sizes and types for my big collection of torches which I like to use and also test and compare with my lumen tube, commercial light meter, and battery charger. I reached an understanding milestone here today.
Wow if there was a quiz at the end of this video i would probably get a solid F lol. Great video man!! You know your stuff!!
Aaron
As always thanks for all the great info!
Thanks for the time and effort it took to make this video 💪🏼
do you not need to update the circuit breaker at the same time? it's rated for 100A.. does it not trip?
Great job at explaining the batteries. Very informative.
If you guys are making a battery for the surron, I would say few things I would want to see.
1. Very good cells for long range rides, and proper shelf life teaching for the viewers on how to hold the battery when not n use/ battery cells should easily be able to do 50,000 miles
2. Very high end BMS so there is 0% rate of anything ever going wrong!
3. Waterproof/ shock proof case, which can take thousands of miles of off-roading, jumps, (rock backs) from wheelie pops. My original 60v battery case is all scratched just from popping the bike hundreds of times.
Someone like me will get on a bike and pop the bike into a wheelie 20 out of the 25mile ride I do. So this is important for the battery's inside to be able to withstand the most friction/movement/constant high power draw, then let off.
4. Go top tier or nothing when you make your battery.
5. Conclusion, SAFETY, QUALITY in cells, bms, build. Durability, and of course! Make the aesthetics a vibe on the battery have the case with a custom e-moto Bros logo. Then you guys will be set!
Those are all super good points. Manufacturability on cases right now is tricky when trying to figure out how to maximize capacity without sacrificing structure. We think we are doing a hard case wrapped in super tough but slick rubber so that when it gets beat up you can just cut off the putter rubber and put on a new one 🤘🏽. We will be using p42a cells with a 400A peak 180A cont. so we feel those are solid for reliability. Thanks for the advice!
@@emotobros Of course! That sounds legendary!! Stoked to see the designs for the cases, also maybe the outside rubber can have orange in some parts to make you guys stand out! That legit is a really amazing idea to have a replaceable rubber outer shell!!
And one more thing pouch sells dissipate heat through the positive and negative tabs very efficiently so you can have a fan on the top where they connect together to dissipate the heat
Only thing I would add is the amp hour ratings are based on a 20hr rate. The slower you discharge a battery the closer to the rating you get. If you discharge faster say one hour you don’t get the full amp hour rating.
Oh awesome info! Never knew that but definitely relevant due to the high discharge rate of these bikes. Do you know how significant the difference is?
@@emotobros I don’t know exact but the number in the solar battery videos I reference is 1+1=2.7. Because doubling the AH make overall discharge rate per cell or battery lower making it get more of its rated capacity
ua-cam.com/video/snaJxB_psg8/v-deo.html. Check this out. It’s long and a 2 part video but lots of good info.
You'll find thats really only applicable (normal?) for lead acid batteries (or gel/AGMs)... most lithium based cells are rated on a 0.2-1C rate (20hr rate equates to a 0.05C rate) - the discharge efficiency of lithium cells is considerably higher, hence the 'faster' discharge rating. You'll get more range out of slowly discharging lithium too, but the contrast isn't as big (think 40+% capacity loss for lead acid at 1C, vs typically
And when he says extremely dangerous he is very correct and he has pretty good knowledge he does know what he's talkin 👍
Emoto bros on top
Does bypassing the discharge side considered a negative than a positive in the battery world ? I’m noticing brands like chi batteries does this and I’m wondering if this is considered to be looked down on, I would assume you would need a bms on the discharge side to keep the battery cells healthy
Bypassing the discharge side is not ideal for a lot of reasons but the main one is safety. Companies do this so they can use a small BMS just to balance the cells while charging while not needing a massive discharge BMS to keep up with the claimed amp ratings which means more space for cells. This basically leaves you with a fully unprotected system which is fairly dangerous. The BMS plays an important role in disconnecting power from your system if things go wrong.
Thank you sir. I just bought a surron and I am a total lithium lamman (kinda like that super hero called ((handi man)) well any way I'm not here to notate my short comings rather I'm here to commend you for explaining something that until hearing your schpeal I figured that I'll use luck to keep my stock 60 v battery alive
And now that I have a beginners understanding I'll never completely discharge my battery 🔋 🙃 but I am definitely going to have the (tim Allen surgery performed i.e. MORE POWER AR AR AR ON MY SURRON ) 72 V I NEED YOU. AS I AM A LARGE FELLOW AND I GOT A FEAVER. AND THE ONLY CURE ISNT MORE COW BELL BUT RATHER IS MORE POWER . THANKS AGAIN 😊
Great content as always! So a 72V battery limited to a lower top speed will have more range than its 60v equivalent?
At equal speed, the 72V will have more range and at equal torque the 60V will have more range.
@@emotobros at equal ah the 72v will have more watt hours as well
@@EdwinOlding yes but a 72v52ah is going to be considerably larger than a 60v52ah
pouch batteries are usually LiPo batteries, found in cells phones and such. They light weight, can discharge very high power. The cost is however, its like the most dangerous battery in the world and will light you on fire, and much less cycle count. If you just want raw power and speed, at the cost of overall battery life, Lipo is the way to go. They can discharge 25c -40c+ compared to 18650s discharge rate of 2-5c. A 1000watt Lipo battery can discharge potentially 40,000watts, where a 18650 will max out say around 3000 watts. Big difference.
Also between 60v and 72v, there is also another variable which is motor and wheel size. In fact, when it comes to efficiency and power, speed, I would say wheel size and motor are more important factors to look into. Basically fast spinning motor, and a fast spinning wheel. Faster spinning is better. Going from a 26inch mountain tire to a 17inch tire and upping the amps will make much more difference in overall speed, acceleration, efficiency than messing around with volts or amps. You'll look like a clown though with that tiny rear tire. Just another option to look at. RPMs is the key, electric motors love rpms.
10 years ago when ebikes were basically mickey moused garage projects, everyone was looking into upping the volts (and amps) to get more speed. Then this dude who knew what he was doing went another route, got a tiny ass rear tire, high wind hub motor (fast spinning/ really high kv).. and put tons of amps through it, and pretty much smashed all speed records. That's why u don't see 120v ebikes anymore.
Also mid drive, like Sur Ron over any direct drive hub motors. Again because of RPMs.
Yesssss this is exactly what i needed to know!!! Thank you so much!
I work for a battery distribution company I did a lot of research on pouch cells in particular the LG 20 amp hour they were took out of a group 48 lithium Porsche battery since working at this battery company called batteries Inc we've had a lot of people trying to dispose of lithium batteries one good thing to know about the Porsche is the lithium cells or not bad it's just a fuse or BMS issue so I have a great amount of these I decided to tear them apart and to salvage the cells little known about pouch cells is they can contain the same amount of pressure as a 18 650 when the 18 650 experience under pressure do not see it because of the casing when building a pouch cell battery they have to be packed in a type of way that holds them together they can withstand up 8 PSI before failing typically you want about PSI of pressure if you have ever took in a pouch sell that blowed it apart you can see how much pressure they can my point being if you have a naked pouch cell yes they will blow up over hilo's and charging when it's cold the 18 650 can also bloat but you don't see it but you can detect it by the amp our loss
Easy.
Buy 72V with BAC8000 if you can and you will have fun lol
I want a long range battery for my scooter any suggestions?
Great straight to the point explanation without dragging on. Any word on your battery release test update?
On our 3rd prototype at this point! Still hoping for a summer release.
House shows or a lower voltage sell than 18 650 at 3.2 volts+ 3.4 in the higher range a pouch cell has the same performance from 3.2 volts to about 2.8 v
i want to get a new battery for my surron but i dont know what to choose. Either 72v 32ah or 60v 56ah. Im looking for more speed since i only ride street. What do you suggest?
72V will give you a higher top speed. I recommend getting a battery with a BMS that has a pre-charge functionality and is not bypassed. Chi batteries for example uses a small bypassed BMS only far charging and has no discharge protections, which we would not recommend.
The LG 20 amp hour powershell can discharge up to 300 amps continuously in a burst discharge of 600 amps 10 seconds at a rate of 30 c
Oh Man ... say it loud .... stock bypass handle only 110A ... the way to stay save 👍
Glad to see there are smart and well spoken people out there. Very well done, and great information given. Can I ask why something like heat pipes hasn't been done on something like this yet? There would be enough space between cells to use them and I'm sure some surface area added for heat transfer has to be better than none. With an aluminum case as a heat sync as a free place to dump more heat I can see it being a logistically simple solution.
There is no room between cells, and it means more weight, cost and complexity to solve something that isn’t really a problem.
@@emotobros I can understand those points for sure. Can I make a video request? Maybe an explanation on all of the controllers including the stock ones. Specs, limitations, tunable points. Hacks and mods, maybe an explanation as to what Luna did to make the xx controller what it is. Just a full run down on all the possible controllers in one place would be awesome.
Pouch cells it had bloated out the sides of the case a little bit when I cut the sides off the cells expanded 3 2 5 x its original size with crazy amount of force they're about the same if contained properly in a battery casing
What about the Sur-Ron battery safety, could you give some more information about that?
Great overall vid. 🙏
Have a 3000 watt ebike kit. Should I get a 60v or 72v? Anyone know what speed I could get our of either?
Can u bypass the 2023 surron?
I have took apart a motorcycle battery that had couch
Very good...Ive been building battery packs for 7 years, I think you covered most of it, however I still have a question that I havent seen answered yet..as I am waiting for my Sur-ron, and am going to either build an extender 60 volt battery for increased range AND, because im joining more cells in parallel (11 stock plus 10 in my build) thats 21 cells in parallel and if I pull the same amps (80 lets say) then the stress and hence voltage sag will be minimal and less than the stock pack. 80/21=3.8 amps per cell. If I increase the amps to 110 for example (that would be 40% increase in torque) each cell is still only seeing 5.2 amps per cell and voltage sag would still be minimal. Here's the question: Cannot the stock x controller handle 72 volts? (84 volts full charge and 74 volts nominal). I see people using the BAC 4000 controller and bypassing the BMS on the LOAD side, which in my opinion is a bad idea...get carried away on your fun ride while the pack is at 54 volts and suddenly you start dipping into 48 volt range and cells that are unbalanced and lets say .2 volts lower than average in the pack get dangerously close to going below 2.5 volts, because without the BMS, you have no way of knowing what the individual series of cells are at any state. I would consider replacing the stock BMS with one of mine that can handle 100 amps now your covered, but still would like to know why or if the stock controller can handle a 72 volt pack.
Great question. I’m under the impression the stock controller cannot handle 72V… but never thought to try it. I assume the controller must be reconfigured to do it. I know my bac4000 has the two settings and you must set it to the correct voltage
@@musicbox4022 stock controller can not do 72v
Thx again guys u are awesome and the info is much appreciated
Great video on tork vs speed with A vs V and general info on lithium-ion batteries 😊 where could I get more info and source parts with building my own 60v Surron batteries out of cells out of a Tesla module? Case, BMS etc
Thanks! Since the market is relatively ‘new’ there aren’t a ton of well done videos on the subject but search on UA-cam how to build a ebike lithium battery and you’ll find some useful info. Most all supplies are sourced from China.
This is excellent
Ok I have a noob question and would really appreciate your feedback.
I have a stock Segway x260 and all I am looking for is extended range as the speed is perfect for the off road trails I ride. I just purchased the Lite Speed 60v50ah Surron Long Range battery. According to the description, I will not have to switch out my stock controller and it will take me from the stock 32ah battery to 50ah for more range. Did I make a good purchase based on my goal of extended range without changing or “pushing” the motor / controller? Your feedback is appreciated
Increasing Wh as discussed in this video is the best way to increase range whether it be 60V or 72V. So yes, good choice.
Thanks for the quick reply. I asked because I have seen zero videos on this particular battery and thought it would be a popular choice and was a bit worried that their are zero reviews. Thanks
You may use different tooth reat star for more torque or speed
Yes something we totally forgot to mention. Many people will go 72V and then run a taller gear in the rear to turn some of that extra speed into more torque.
Tesla's new 4680 batteries are going to be great!
Some people add an extra 0 to the dimensions for some reason? It should be 2170/1865.
Right?! Can’t wait to get our hands on some. I explain why they add that zero in the first couple minutes 🤘🏽
Sorry, missed that😁
I watched the whole thing again. I'm fairly familiar with battery chemistry after following Tesla and Jeff Dahn for years. Your explanation is very good, as usual:)
Excellent explanation!!At 66 I thought I couldn't fit any more into this overloaded brain.Guess I was wrong again!Xr600 used less,Sur Ron used more.One question.Can a 48 volt Sur Ron battery be built to 60 volts by adding more batteries?Can Bms be utilized for such or would it have to be changed?Thanks for your excellent video!
Very good explenation.
Good stuff
best video thnx!
So I've got a 72volt lipo in my razor... it charges to 87.7volts... if I buy a segway x160 I could probably use my same lipo I have now with a proper controller and itd be a dope surron yes???
You could, yes. Do note that the x160 had a slightly less powerful motor so not the same as the x260 or the SurRon.
@@emotobros its gotta have a stronger motor than the 3000watt mid drive motor I've got pushing 7000watts from... and itll be so much prettier lol thanks
@@emotobros I don't think there's such thing as a used surron.. and if there is itll be more than a stock one prob with upgrades... kind of my only option. I been clean for a little over a year and I'm hooked on these things. But can't really afford nice things although I'm trying for sure..
But you don't ship to the UK 🇬🇧
this video is good and accurate though there is an exception to everything said here and an argument could be made to suggest errors but this is very accurate but you start getting into batteries made graphine or graphide and or with cooling systems or BMS systems that governed to prevent max or minimum charges can have a world of difference in capacitance or discharge.
like some people max charge and max discharge their phones or bikes or cars you name it this can cause severe battery degradation and a degraded battery get more dangerous the more it is abused by lower quality BMS.
a good quality BMS will deliver more poor performance as it degrades providing longer life or a poor BMS will rock hard till you get that nasty smell and then brick.
i try to avoid letting any and all batteries from having a full cycle buy discharging no less than 20% and stop charging at 80%..... this will give you max battery life but this remove 40% or your range!!!! so in my 320 mile rated tesla i really only get less than 200 miles per charge. hence why im thinking to buy a second battery for my new bike.
you often get about 5000 cycles aka charges per 18650 cells.
long as you stay with in battery tolerance being about 8% min and 91% if you abuse your battery to discharge lower and charge higher you will get less cycles if you stay between 20 and 80% you are doing micro cycles possibly doubling how many charges you get from battery.
problem is you rarely get much peak performance with an 80% battery and voltage drop occurs about 70% so with a good BMS you should see a decline in output the lower the battery gets but a bad BMS could over draw =heat =death of cell
1st problem with electric limited range
2nd performance fall off
3rd down times of charging!!!
but that torque nearly makes up for all the flaws
What is the formula for torque?
As in determining torque at the wheel?
Force * Distance is the basic formula for a moment.
always go for higher rpm and higher gear reduction for torque, an electric motor has the highest efficiency at higher rpm. I would always go for 72V or even higher and use a bigger sprocket for more torque. You can get the same torque as a 60V System at the same power level, but with more efficiency as the datasheet of surron motors shows.
Yup, heat buildup is wasted energy, minimizing amps through the motor reduces heat and improves efficiency
I'm looking to get more power but not crazy power (7000-9000W) but also a little more range than stock. Is there a battery and controller that would do this? Maybe a 52AH and a BAC4000? Could i then also use my old stock battery as well?
Yep, 4000 and 52Ah 60v will also work with stock battery. Basically same setup we run.
Would a 60v 63ah battery work as well with your BAC4000 and your 58T sprocket?
There is little-to-no information about pouch cells unless you read through a bunch of boring chemistry books if you want to hear more about properly making a pouch cell battery let me know in the comments
If you program the controller for Lightspeed 72v I assume I can still use the stock 60v battery for dinking around the on property or while the 72v battery charges? Switch to a lower setting?
Nope, not how that works. Once the system voltage is set at 72V you need to be using only 72V batteries. If you would like to utilize your stock battery you should purchase an upgraded 60V battery.
In the future will the bac4000 have an option to easily switch between 60v and 72v? Alot of Chinese controllers handle any thing from 40-100v. Just curious if this could be an possibility. Btw are the bac4000 going to be in stock soon?
@@organicoceans4459 they do now. Eggrider will let you switch voltages. Also GLE app works.
arf j'aurais tant aimé voir cette vidéo en français! Quelqu'un pourrait il m'indiquer si il existe un moyen de traduire cette video, sans trop de perte de temps?
You '' bypassed '' the cell data sheets... Every cells have different characteristics
SORRY THIS IS A REPOSTED QUESTION BECAUSE THE VIDEO I ORIGINALLY POSTED TO , I REALIZED IT WAS A LOT OLDER.... Hey buddy.... I'm new to your channel and just subscribed. I would like to see if you or your subscribers can offer me your opinion on a sur ron. I know there's the x-controller and 2 others like the 400 or 800 bac controllers, plus a few battery upgrades from larger 60v to different size 72v. So....... I'm a 250LB man and what I'm looking for out of this setup is 50mph with the longest range possible hopefully getting 40 miles riding 35-50 mph and 85% of the time on the streets. ANY AND ALL OPIONS WOULD BE GREATLY APPRECIATED. thanks!!!
This set up would be the most efficient for what you’re trying to do. I have a 72v 40ah battery with a ASI BAC8000 controller. I’m doing 13.5kw max and I’m a 170lb rider I get a range of about 30 to 40 miles of range going at speeds of 45-55mph. I get 20-25 miles going at speeds 55 to 65mph. Just know that this set up is very expensive and I highly recommend you upgrade your suspension, tires, and brakes. Please be safe and I hope this helps.
@@stevennguyen8250 hey.... thanks for the help and input.... about your 72v 40ah battery.... is that made with 18650 batteries 21700 batteries or ive seen them recently made with a type of bag or pouch batteries. Is that from litespeed if not where do you recommend shopping for a battery...... THANKS AGAIN..... and yea its expensive but you get what you pay for... I've always believed...... buy once cry once.... meaning it will hurt to spend xtra to get quality but it should last MUCH LONGER THAN BUYING CHEAP
I highly recommend Litespeed that is where I got my battery from and my battery pack is made from 21700 cells. Talk to Chris and tell him I sent you he’s very reliable and good at his job. If you’re going to upgrade your battery and controller please get a better wheel build and upgraded brakes. Just make sure you balance your tires you will experience speed wobbles at 60mph and above.
@@stevennguyen8250 yea its alot of cash... I just bought a 3,000 dollar kaabo wolf warrior 11 electric scooter and dropped another 1,000+ on xtras but realized I'd rather a bike to sit when I'm using it as transportation so my plan is to drop the 4,000 on a sur ron and slowly drop a 1,000 give or take on brakes,tires,forks, then ride stock battery/controller for a month or 2,and then ill drop the 3,000.....lol.....GIVE OR TAKE on the 72v battery and the controller 8000...... its gonna be a hard 8,000 dollars but I THINK EVEN AT 250LBS IT WILL BE VERY WORTH IT! AGAIN THANK YOU FOR YOUR HELP!!!!!
Yep 👍🏽
Wow
746 Watts = 1 HP
That it does. Power to weight ratio is also a huge factor when comparing a SurRon to a gas bike.
So you would have to have 24 cells in series to make a 72
Sorry mate but so much in this is so far off the mark that its hard to know where to start... I know you mean well and all but your attempt at simplifying it necessitates at least understanding the fundamentals of how motors (particularly BLDC and similar) produce torque, and how it relates to battery voltage/power... just saying 'this is nuanced' all the time doesn't actually mean you understand it or are simplifying it...
For instance:
/Torque is determined by phase amps... not battery amps. The 60 vs 72V version you give at around 12:30 is flat out wrong... both systems will produce the same torque at the same rpm, despite the difference in voltage... because its battery POWER that determines torque, as that is what produces phase amps in the motor.
/Phase amps at a given RPM require a given amount of power from the battery. Doesn't really mater if its 72 or 60v... it needs x power for x torque at x rpm. So you have to draw more current from the 60V battery to produce the same torque at a given rpm.
/Double the rpm, you need double the power for the same torque
/double the torque, you need double the power for the same rpm
/double both, you need 4x the power for 2x the torque and power.
/ ergo, a 60v battery is not more efficient than a 72v at a given torque level. on the contrary, unless its a more efficient (larger capacity and/or lower IR cells, thicker battery cables etc) pack its probably less efficient, and certainly the wires from the battery to the controller will be more lossy too (read, more voltage sag).
On some other points:
/Pouch cells are not inherently lower cycle life, or more saggy. On the contrary, they're generally less saggy due to better internal connections to the 'outside' (lower internal resistance) - there's a reason the new tesla cylinder cell is so much higher power, and its a lot to do with brining pouch cell advantages to a cylinder cell... and chemistry has far, far more to do with cycle life than does pouch vs cylinder. cycle life of either type can be in the 1000's or in the 10's.
/ the packing density you talk about is simply wrong. if you want proof- calculate the surface area of a single 100mm dia circle, then the surface area of 4 x 50mm dia circles. Clue... they're the same, and both will fit in the same square box, and thus, so is the energy density of cylindrical cells in a given volume. you may be able to fit more smaller cells in a pre-determined size of casing, but unless thats constrained to a non-interger multiple of the large cell, then its not a factor at all.
/
there's more mate, but honestly your selling this shit and speaking as a source of knowledge, clearly without the knowledge to do so. While there's nothing in this vid thats likely to get people hurt, this attitude that runs through a lot of the posts you make on FB or on YT will eventually cause someone to make a mistake that could have been prevented by you simply putting in the time to gain the expertise you need to speak on these subjects (as ive seen happen with some of the kits you've sold). I'm always hesitant to be too harsh, but this is not the first time you've done this mate. Take it from a guy who does know... you dont know enough (yet) to be publishing guides or info on these subjects, targeting the 'everyday joe' or otherwise. While I welcome more people onto the EV grin bandwagon, publishing misleading bollocks is only going to get our hobby more overregulated by overzealous gov's than it already is. There's been calls in the past to ban cell sales to end users, and this is only going to add fuel to that fire, figuratively and literally.
Hey thanks for the comment and I'll address these one at a time.
To begin with, torque is not determined by phase current outright. Of course battery current isn’t what is going directly into the motor so that’s taken a bit out of context with you insinuating/thinking that’s what I meant, but really where the current is coming from isn’t exactly relevant to the argument. Torque is a response to a load, not the other way around. An increased load creates an increase in drawn current from the battery. If you were on a slope of 1 degree, the torque needed to overcome the force of gravity pulling you down the slope would be minimal and the current draw would reflect that. If you were to increase the slope to 45 degrees, you’d need a lot more torque to keep the bike from being pulled down the slope by gravity which would require a much greater draw of current than the 1 degree slope regardless of voltage. My argument was never that unfiltered DC current was what was being put into the motor. I’m aware that the controller controls power levels to the motor using pulse width modulation; however, it didn’t seem relevant to the argument since all that does is complicate things unnecessarily. The bottom line is that an increased load needs increased torque- which requires a higher current draw to overcome.
Equal levels of phase current while drastically varying the input DC current will not produce an equal amount of torque. It is more the time derivative of torque that is determined by phase current (the parameter itself not the actual current). Technically speaking, torque at an RPM is based on phase current so in a sense it determines the torque, but that's somewhat of an oversimplification considering an increase in phase current doesn't pull more DC current from the battery at the peak, and peak times from low to high phase amps are shifted, but in our case, not by more than a few seconds. Anecdotally, the phase current parameter has more to do with power ramping from a stop, and twitchiness of the throttle when considering its effect on the Sur Ron. This has been plotted in great detail on our instagram.
For the difference in battery voltage vs. efficiency. Torque can also be said to come from power since voltage can be considered constant and as we mention increased current increases the torque. Therefore an increase in power (from voltage) SHOULD lead to a proportional increase in torque. However, this is only for the 100% efficiency case which I mention. I clearly state that the increase in power (from higher voltage) will result in the increase of torque but not at the same ratio as the power is increased at. What happens mathematically is not necessarily what it will do under real conditions especially considering that all mathematical models are an approximation.
Addressing our claim that a 60V battery has more torque at the same power levels than a 72V battery: This is not a new or controversial statement. A 60V needs to have a higher current than the 72V to reach equivalent power. This is far more relevant to stall torque (and overcoming it) than it is under average riding conditions.
You're right about the sag from a technical standpoint although there isn’t a lot of literature on the topic. “Inherently” was definitely not the correct word to use and pouches do in fact have a lower IR which would inherently lead to LESS sag, I see that error. I should've been more clear that the increase in sag from pouch cells have been directly noted from testing pouch cells batteries for the SurRon vs cylindrical cells. Certainly not always the case but it was for the ones we've observed/tested, and what is relevant for the video. I would say this is generally due to a lower output rating of pouches in comparison to cylindrical cells where the BMS/Motor is the limiting factor. Under low draw conditions pouches may have a higher cycle life and less sag but under high draw conditions, which the SurRon produces, it seems to lead to a lower cycle life and more importantly swelling.
Regarding the cell packing. It seems unfair to say "unless that's constrained to a non-integer multiple of the large cell", because it is. This is going into a SurRon that has a very specific battery compartment size which can't be changed just to optimize the fitment of larger cells. Smaller cells give more freedom in POTENTIALLY increasing the energy density. I should've been more specific about that but again this is for the SurRon not in general. You're are correct that if that box size is an integer multiple of BOTH cells that it'd be equal in capacity. The tradeoff being that the smaller cells will build heat quicker due to smaller air gaps. The main takeaway was supposed to be that the larger cells give less freedom for battery sizes and beyond that these cells only seem to be getting bigger (ex. The new 4680 at more than double the diameter).
Saying we are ‘so far off the mark’ seems like a stretch. Basically every point you addressed is far less useful to the average joe (our audience) than the simple power calculations and general information that we gave. Going as far as saying videos like this are the reason for more laws being created...seriously? Even if someone who had the power to create these laws did watch this video, I highly doubt that’s what would be taken away from this video and at the end of the day being ‘technically’ wrong about phase amperage, cell packing and pack voltage vs. efficiency certainly is no reason to create laws.
We actually aren't selling anything related to the video so I'm not sure what you mean in that regard and you're only gripes seem to be highly specific and nuanced in their own right. We are always open to expanding our own knowledge, and do not shy away from correcting ourselves when we are wrong. That being said, we hope you understand that we do understand these things quite well and will occasionally simplify things for the audience. We do not feel this diminishes our credibility or our ability to educate people on the subject. We have done a lot of research on these subjects as well as completed college level courses on the fundamentals of these subjects as well. While we may not be leading experts in the field, but we are trying the best we can.
@@emotobros @E-Moto Bros I appriciate the tone of the response, but mate, your still missing some major points here... I'll start with one of the more significant since it highlights the problems you're repeating.
"Addressing our claim that a 60V battery has more torque at the same power levels than a 72V battery: This is not a new or controversial statement. "
Oh, but it really really is. put simply, thermodynamics. Unless the efficiency of the system is somehow dramatically more efficient at 60v, then this is physically impossible - and I'll tell you for free the efficiency doesn't change significantly.
This statement is simply flat out wrong. Power output is a linear function of torque and rpm... so if you get more torque out, then your outputting more power. You cant get more torque out of a system 'at the same power levels'... it just aint possible.
"Torque is a response to a load, not the other way around. An increased load creates an increase in drawn current from the battery"
No. This was 'kind of' the case with old style PWM controllers/brushed motors (though not really) but not at all for modern torque based systems, like the BAC. The controller has direct control over the phase currents, and as such direct control over the torque. The only time it cant produce that torque is once back EMF is high enough to limit the phase currents rather than any pwm'ing... the load only factors on how quickly the motor/wheel responds to that torque (ie accelerates).
Again... its the phase current that determines torque - it will do so no matter what the load. Increasing torque does not require increased load, it requires the controller to push more current into the motor.
1. motor rotor is in position x
2. controller applies phase currents at 90deg to this
3. interaction between stator electro magnets and rotor magnets produces a turning force on the shaft
4. motor turns, if it is able/torque is sufficient to overcome any loads being applied.
5. repeat from step 1.
If it was only a response to load then the acceleration of the wheel would be a constant for all loads, up to the max torque.
"The bottom line is that an increased load needs increased torque- which requires a higher current draw to overcome"
Not when comparing 2 different voltage batteries. The higher voltage battery will draw less current to produce the same torque, in direct opposition to your claims in this vid.
"Equal levels of phase current while drastically varying the input DC current will not produce an equal amount of torque."
Yes it will. Phase current determines torque. The input current, as it pertains to torque, is irrelevant. 100V 10A draw or 10V 100A draw form the battery - if there's 150phA in the motor, then the torque on the shaft will be the same.
go back to basics. There's a certain turn count in the motor, of copper, around each tooth. And a certain current in those turns... a certain number of amp turns... These amp turns are directly driving the flux in the air gap, and as a result of the interaction with the rotor magnets, the forces on the shaft (namely, torque).
Try to think of it from teh motors perspective. It never 'sees' the battery voltage - you can confirm this yourself with a multimeter between any 2 phases... it will be < the battery voltage (at least for lower rpms), yet torque can vary wildly all the same. If the battery voltage never appears at the motor windings, yet the torque can vary between 0 and 100% of what's possible, how is it that battery voltage can possibly be influencing the motors torque?
The answer is that it isn't.
"but that's somewhat of an oversimplification considering an increase in phase current doesn't pull more DC current from the battery at the peak,"
Yes, it does increase current draw from the pack. It has to - because increasing torque at any given rpm will increase the power output of the motor... so unless you've increased the efficiency of the motor+controller somehow (see first comment re thermodynamics), there's simply no way to increase torque without a corresponding increase in power draw. Its not even a matter of motor knowledge at this point... its basic thermodynamics. torque x rpm = power output (must be less than) power input = battery voltage x battery current. you cant get more power out without more power in...
"Anecdotally, the phase current parameter has more to do with power ramping from a stop, and twitchiness of the throttle when considering its effect on the Sur Ron''
And this may give a clue to the problem... how it feels is not how it 'is'. that snappiness is the faster ramp up of phase current over the same throttle movement... ie... more torque for the same throttle input. And again, if power input is ramping faster... then (almost by definition) so is power output... because more torque at the same rpm = more power output...
"I clearly state that the increase in power (from higher voltage) will result in the increase of torque but not at the same ratio as the power is increased at."
This is the same regardless of voltage, more power draw = more torque. increase torque by 20%, you'll need to increase power by at least that amount ... whether its a 50v or 100v battery. If anything, the lower voltage battery will be less efficient, due to higher losses over the same size cables between the battery and the controller. yes, you do get higher switching losses at a lower duty cycle, but this is marginal enough to be irrelevant.
"You're right about the sag from a technical standpoint although there isn’t a lot of literature on the topic. "
There's literally tones of it. perhaps not directly related to the surron, but then it doesn't need to be.
"and pouches do in fact have a lower IR which would inherently lead to LESS sag, I see that error."
No your jumping too far the other way. Pouches CAN, but its not a rule. I know I'm somewhat focusing on semantics here but the point is that cell config (pouch vs cylinder) doesn't directly impact performance, certainly not relative to all the other factors/enough to generalise either way.
"... less sag but under high draw conditions, which the SurRon produces, it seems to lead to a lower cycle life and more importantly swelling."
again, purely anecdotal. You can find any number of cells of either configuration that will perform well, or terribly. The pouch vs cylinder is completely irrelevant next to chemistry choice, internal architecture etc etc - this is my point here.
"This is going into a SurRon that has a very specific battery compartment size which can't be changed just to optimize the fitment of larger cells."
Fair enough if talking specifically on the surron, sorry it came across (particularly after the pouch cells points) as a general remark. though by the same token, the two common form factors (21 and 18) fit the surron well...
"Going as far as saying videos like this are the reason for more laws being created...seriously? "
I certainly dont think this vid itself will lead to more regulation. What I do see happening though is more and more people getting into this hobby, watching a few vids on the subject, and 'burning their house down' as a result. Part of what will cause more accidents is incorrect information, and poorly designed equipment being given to laymen's to install... as I have seen happen with your guys stuff once already, where a combination of poor choices of hardware, and poor instruction (not just from you, to be fair) has already lead to one of your customers getting a major fire....
"That being said, we hope you understand that we do understand these things quite well "
I do appreciate the openness and am all for people sharing their knowledge. But as mentioned above, there's some simple, fundamental things your getting wrong that will only serve to further confuse people on this subject, yourself included. There's simple and easy ways to explain it without breaking fundamental laws of physics - and its a dangerous situation when you make this kind of claim when you clearly dont... if you understood these things well, then you wouldn't be saying / doing / selling the things you are, and touting yourself as a point of information is only going to cause others to follow you on that path...
"We actually aren't selling anything related to the video so I'm not sure what you mean in that regard"
your claiming to be a source of knowledge/expertise on the subject, yet you're making mistakes again here, that are similar in nature to mistakes made previously with what you do sell. Like I said above, I dont think this vid itself is posing any major risk per se, but your body of work can (and has) and this vid is reminiscent of the mistakes you keep making, and not correcting.
" as well as completed college level courses on the fundamentals of these subjects as well."
And your talking to a specialist who works with motors measured in the mega watts, with torque outputs literally, not figuratively ... in the region of 10,000 times higher than the surron motor, and been building + modding emotos/ebikes for ~ 10 years... Oh, and ive 'completed collage level courses' too.
That said, ive also known 'experts' and guys with masters/doctorate degrees that couldn't handle the most fundamental basics, and guys with no degrees at all who could make me look like a fool. So if an argument from authority is 'valid' then I think I safely 'out authority' you... else arguments form authority don't prove anything, in which case, dont play that card.
Point being, its not a strong argument to make an argument from authority. The fact that you or I have x experience or knowledge doesn't make a wrong answer right.
I mean this honestly, I wish you guys the best and im all for more people contributing - but im not sure your really living the 'do not shy away from correcting ourselves when we are wrong' mantra. When things have gone wrong in the past you've been quite insistent that it was not your fault, or the fault of your kit, but the fault of other elements of the install - when the simple fact is that multiple elements contributed to the fire, including your own workmanship/kits/advice. Now here you are breaking the laws of thermodynamics to prove your point, rather than take a moment to check what your claiming is even possible.
@@sn0wchyld Reading and writing replies in this thread is becoming quite laborious so I figure we will just link exactly where our information is coming from and you can feel free to list discrepancies you have with it:
Everything we've said is coming from this very accurate motor simulation model: ebikes.ca/tools/simulator.html?motor=ST-HM-03&batt=cust_60_0.2_52&wheel=19i&mass=50&hp=0&mid=true&gear=1.5&tf=30&tr=11&cont=cust_330_430_0.03_V&eff=94.1&axis=mph&cont_b=cust_330_430_0.03_V&motor_b=ST-HM-03&batt_b=cust_72_0.2_42.5&wheel_b=19i&mass_b=50&hp_b=0&tf_b=30&tr_b=11&mid_b=true&eff_b=94.1&gear_b=1.5&bopen=true
Every parameter simulated between the two tests are literally exactly the same (including the battery cell count) with the only difference being the input voltage.
As you can see:
-If you set the torque of each system equal to each other with the sliders the RPM of the 72V system is higher (as we suggested), the power draw of the 72V system is higher (as we suggested) and the motor current/battery current are within 2% of each other (as we suggested).
This is how we came to the conclusion that the same amperage levels give the same torque despite the 72V using more power, therefor it is less efficient and will reduce range at equal levels of torque. You also said that at the same RPM the torque levels are equal; we are also not seeing how this is possible based on these simulations (All comparison were done pre-peak power or post-peak power so that we weren't straddling the dome). We do notice that the efficiency of the 72V system is a bit higher in the motor but a 3% difference isn't making up the multi-100Watt difference in power draw that the 72V is using at the same torque.
Now it is entirely possible that we completed are misinterpreting the data, but I don't think laws of thermo. are being broken in this simulation and it is also a lot more advanced than a basic linear model without efficiencies. If you could please post something that proves how we are misinterpreting the data or how the model itself is wrong that would be much appreciated because clearly we are missing something as you seem highly confident that we are wrong.
@@emotobros I had half thought to write a reply pointing out each place where you're missing / misinterpreting something but I'll try to keep it short and sweet and focus on just 1 or 2 points:
"Now it is entirely possible that we completed are misinterpreting the data"
This is the issue here... let me explain:
"This is how we came to the conclusion that the same amperage levels give the same torque despite the 72V using more power"
It uses more power because your going FASTER... More fast needs more gogo juice... ffs dude, look at your 'load' value... its higher in your example on the 72v system so of course it needs to draw more power.
"but a 3% difference isn't making up the multi-100Watt difference in power draw that the 72V is using at the same torque."
And you state that you understand the relationship between torque and power - indeed, its in the blurb 'how to use the simulator' on that very link you provided... yet somehow you say that 2 systems of near equal torque outputs have vastly different power requirements? Why do you think this might be the case? Again, look at the load your 2 systems are under, and the speed they are going.
" therefor it is less efficient and will reduce range at equal levels of torque"
Mate.... the very thing you just sent TELLS YOU the system efficiency - its the litte green numbers under the graph next to the term 'efficiency'. And the system efficency of the 72V system is HIGHER in the situation you describe
(This is my point re 'misinterpreting'... The very thing you're using to prove your point emphatically refutes it....).
Part of the issue here is your using an ASI motor... this is not the surron motor with your ASI controller parameters, so you're not going to get a acurate picture about what happens on this bike. You've also set your battery perameters at the same IR... which is unlikely to be true, and 0.2ohms is pretty high too, hence why your battery is sagging so much. These 2 factors are why its never drawing anything like 330A, or putting out 430phA. Your never seeing the phase limit on your controller, hence why the graph you have here has no continuous torque section at all...
ebikes.ca/tools/simulator.html?bopen=true&batt=cust_60_0.2_8&batt_b=cust_72_0.24_6.66
This is a more representative example of whats happening on the surron between the two batteries. I've equalised the power capabilities of the 2 batteries (proportional IR and capacity). at high loads and low rpms (where the blue torque curve is flat) both systems produce the same torque, because the controller is at its max phA limit (in this case, ~40A, but the same would happen for the surron motor if you input it with your controller). As you can see, the higher voltage battery has the exact same efficiency curve, to the point where the power limited zone of the 60V battery is reached. The 72V system is less efficient from this point on... but this is because its producing more torque at that rpm... by being able to push more phase amps at that rpm.
"as you seem highly confident that we are wrong."
Mate, you are... Your telling me that the 72v system is less efficient by linking a simulator that shows its more efficient... I'm not sure how else to explain it. it doesn't even require interpretation of the results, you can just read the data right off the table, or the graph.
As to your earlier comment, ill just grab one section:
"If two college aged adults who have only been in this industry for 6 months is your only source of information, especially after informing people in the first 45 seconds that we will be wrong about things, then I'm not sure what to do about that but we aren't going to shut down our channel and business because we've said something that wasn't correct."
dont be rediculous. I've said repeatedly that im all for you guys doing what your doing... but there's some stuff your getting wrong, quite wrong and some of it poses a danger, particularly when you guys are building a resonable following. The tone of some of my responses might be a bit 'harsh' but its due to your defenciveness on a few points here and prior, and your continued insistance that 'we know what we're doing' despite all the evidence to the contrary... see above RE your claims on 'efficiency'. And if your confidence in your abilities is so low, why are you calling this the 'ultimate' guide to anything?
There's plenty more I can say but in the interests of keeping things (relatively) short... ill leave it focused on just this. Happy to explain further if you need.