Everything you NEED to Know BEFORE Building OR Buying an E Moto Battery
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- Опубліковано 4 лют 2025
- You might want to get a notepad for this one. If you've been wanting to learn all you can about batteries, this video is packed full of good info.
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This is the forum I used a bunch while planning my build:
endless-sphere...
Here is the link to the place I got those busbars:
www.alibaba.co...
Dont order from this page if you want custom. Message the company, Ken should get ahold of you. Remember I'm not affiliated at all and cant promise a good experience, just sharing what I did.
Its 21mmX70mm and 18mmX65mm. I dont know why I said 700 and 650. I need to stop filming and editing late at night. Thanks for watching. I'm sure I'll have a lot more mess ups but we're getting this video thing figured out slowly so it should get better.
Hey dude you are spot on when you said "run a smaller battery at higher efficiency '
I'm sacrificing battery capacity for active water cooling the controller and battery pack. In my opinion that reduction in heat from cooling, lowers the resistance therefore increasing efficiency. Then cooling adds weight.
Because the battery is the most expensive part to doing an EV build, you want to reduce battery degradation as much as possible for as long as possible ideally
I'm really excited to see your cooling system
@BlacksheepEngineering it's just conceptual at the moment. I need the motor to get it positioned so I can idea of space the battery. Because I'm wanting to cool the bus bars in particular and ceramic being the only martial for me up achieve this with; depending on weight Peltiers (that are made out of ceramic material) means I can either use ALL Peltiers or some "tiles" Peltiers and some normal ceramic tiles of the same dimensions (depends on weight) the idea is that they will conduct heat to transfer from the battery to the coolant. Because Peltiers can induce cooling when a voltage is a applied; likewise when the temperature differential between the cooland and the bus bars, they effectively become tiny generators that will produce a voltage albeit not a lot of current will be generated because it's inefficient and the Peltiers selected for cooling (they can both cool or heat depending which way the polarity is on positive and negative)
The secondary use for Peltiers is applying voltage to actively cool (it will freeze with ice crystals. This would directly cool the bus bars on 1 side of the Peltier; whilst on the opposite side of the Peltier is will be generating lots of heat when voltage is applied, but that's ok because that is contact with the water cooling system that water can be pumped past to dissipate heat.
In my opinion this could be ideal for mitigating a thermal run away event, perhaps? It is just something worthwhile testing because it could work?
Peltier tiles are what they use in car and camping fridges btw.
Note: I'm aware of the parasitic energy loss on the battery that it's trying to cool but I think stopping riding the bike and just giving all voltage "bandwidth" to the Peltiers to prevent a thermal runaway from occurring in the first place?
It will require dual thermal sensors because activating the Peltier will result in feeling like more heat than normal is being produced by the system.....when actually the opposite is the case 😉
Running a thermostat to turn the Peltiers on if a critical temperature is reached? Well that's the idea anyway? That being said having it not activated all the time; I can't see it adversely affecting the battery?
Worst case scenario is they are just fancy ceramic tiles with wires coming out and they do nothing but be a ceramic tile, like no big deal?
Famous last words 😆
You can put a coffee cup on a Peltier and either freeze a cup of water or boil it 😲
Run the red and black from the Peltier to USB cable. Suspend the Peltier above a candle and plug the cable in to your phone and it will charge the phone (Albeit very slowly 😆)
There have been technological developments in chip manufacturings circuit board fabrication(multi layer wafer boards etc). Back in 2016 scientific studies lead to developed of improved gas vapour deposition process dramatically improving all chip manufacturing, but in particular they discovered a new thermocouple design! This lead to active electronic cooled coatings! No ceramic tiles, simply apply voltage across 2 designated points on the part and it can be actively cooled or heated! Think on the weight saving alone 😲
Peltier coating material applied directly on and surface you want cooled (or heated) either inside or outside, excuse the pun but that would be so cool 😎
great one, thanks.
Awesome, thank you.
Thanks for sharing the stl files on endless-sphere. I'm planning my custom battery order from amorge. I'd like to hear about whether you are going to build an open discharge battery where the discharge does not go through the BMS. This is a decision point for me. Each side has pros and cons and implications for the rest of the wiring on the bike. Love the detail in your vids. Some of it I've already learned by my own research but there are bits here and there I had not considered.
Thank you! I am running the discharge through the BMS, I'm not too worried about issues with the one I got but I will share feedback when I do.
Just as said previously I believe p45b would have been a better choice for your build. If you are planning to run 28kw peak that would mean a peak discharge of 270a or 19.2a per cell. I believe that at such amp draw p45b would be a better performer in terms of capacity and definitly voltage sag.
All the independent testing I have seen of the 50S actually does really well at that amperage. As long as you're more in the range of the 17-19 continuous and 25 peak its one of the most energy dense cells on the market and doesnt show voltage drop issues. People just hate it because thats not what they're selling it as. The P45B would take more amps, but at this level of amps there is not nearly enough voltage drop in a 50S to make up for the greater capacity.
4:33 just a few corrections here: Prismatic doesn't equal LFP batteries, it's just the shape of the cell and how it's built. LFP batteries exist in cylindrical and pouch-format too, just like NMC cells.
4:53 It's also untrue that they're really size efficient, Wh/l is also noticeably lower than that of NMC counterparts. Still great cells though and their 25+ year lifespan is awesome.
5:28 also somewhat untrue, new 46xxx cells like 4680, 4695 and 46120 can have a very high energy density, upwards of 270-300 Wh/kg.
9:36 The continous rating will still build heat (all forms of discharge will to varying degrees), and in a large enclosed pack without any cooling is absolutely something that you won't be able to sustain forever. 25A continous means discharging the entire pack in 12 minutes, so it's still likely not something you'll have to worry about in a build like this.
Also 21700 means 21 by 70 millimeters, not 21 by 700. 😝
Still great video and appreciated watching it! 😊
The MM mishap was very dumb lol. I'll get this video thing figured out eventually. Thanks for the support.
Also have you heard or looked into lithium king motor mounts? For the qs 138
Electric Motorcycle Builds is very very established group! you should join there
Thoughts on amorge batteries?
Thanks for sharing, 18650 is 18mm diameter by 65mm long, and 21700 is 21mm and 70mm, you said 650mm & 700mm. Not dissing, just a heads up.
Yeah, still working on keeping my brain from shutting off on camera. We'll get there eventually. Thanks.
Are there extra precautions or safety considerations going from 72 (20S) to 96 (26S) or even higher? For example, if someone were choosing between purchasing a 72 or 96 volt battery and controller, what might need to be different on those builds? Other than obviously getting components (switches/fuses/etc.) that are rated for the appropriate voltage. I'm asking more about design differences if there are any. And if the precautions change while working on the bike at those two voltages.
For safety concerns, you should be just as careful at lower voltages but the fire and boom could be a lot bigger at higher voltage so I guess the stakes are a little higher.
The biggest factor on determining ratings of connectors, wiring, and such is actually based off amps so if you switch from a 72v to a 96v system and your kW stay the same it actually reduces strain. The controller and motor need to be rated for the correct voltage though. The controller will say its peak voltage capability but motors can usually take higher voltage (and amps) than they say so I would look at what other people are running that motor at. I hope this answers your question.
@@BlacksheepEngineering yep. thanks!
Your math on C rating is wrong. A 10ah cell with a 1c rating can produce 10amps. Your 45 amp peak 5ah cells have a 9C rating not .9. Been following ur build, wish you the best but I’m pretty skeptical you can build a bike with bigger battery, similar component weight yet lighter than a Stark. What are using to protect battery and have you factored in that weight?
Wow I cant believe I didnt catch that in editing. Thanks for saying something. I'll see what I can do to fix that in the video. I'm working on a custom built battery housing design. Should only add about 5lbs. Its part of the weight calc. Obviously the real world is different than CAD land so we will see how close it turns out.
Also you use 3.6 for nominal voltage on Samsung 50T, so ur battery is 100.8v x 70ah or 7.056KW not 104x70 or 7.28KW. U may also not get the performance/range out of 50T’s that they claim vs a Molicel P45b cells that Stark uses. Lots of accounts of those cells not getting near 5ah, specifically when ran at 20amps or more. Watch some vids on real world comparisons of those cells. Stark’s new battery with p50b’s will probably be used in all future stark batteries and are even better.
The claimed nominal voltage of the cell isnt the important number. The pack has a max charge of 117.6v like any other 28s battery. These cells are the 50S
My apologies Samsung 50s, this is still the one that under performed. The nominal voltage does matter when calculating total pack kilowatts.
@@thetraccer Correct, but I am in the correct range for that cell, not the claimed range.
I may be wrong on this, but the general consensus from the experts I have discussed this with is that the 104V number is the correct one to base it off of. If you post about the listed nominal voltages in forums you usually get laughed at.
can build a 420wh lfp battery (4s1p) for 60 bucks, weighs 5 lbs. when taking into account packaging, lfp actually wins on weight coz prismatics are so much more efficient. use 32ah lfp cells to build my own power stations. dirt cheap, better than anything sold and much smaller than the cylendrical cell versions which have no water protection and a regulated 12v port.
Theres another comment on here arguing that even on size prismatics arent close to as efficient as cylindrical cells. Let alone weight. Id be interested to see where a constructive discussion between you two ends up. Thanks for sharing.
wouldn't using bigger cells reduce the labor needed to pack these? i mean 30pcs of 46950 liitokala cells would be about 3330 watthours and 111 volts, 12450 grams
Yes, labor is definitely a pro to using bigger cells