@@3dxyz412 it’s impossible to get perfect because there’s a lot of variables... So I always calibrate my sensor so the Current (Amps) & mAh Used display are slightly higher than actual. This is the safest way to do it. With a couple tries you can usually get it within 5% of actual. Basic Process: Fully Charge a Pack, Fly/Drain it, Note the mAh Used, then Charge the pack & Note the mAh Hours Charged. The difference between the Used & Charged is what needs to be calibrated. Oscar Liang has a good write up in the Calibration Process with the calculation used to set the amount. Note: Also check your Voltage Readings. This is easy & usually pretty accurate, but Current (Amps) always needs to be checked & set.
@@3dxyz412 Every single quad current sensor I've measured has been noticeably out, usually ~10-20% - some worse than others (iflight ESC's especially). The answer is to calibrate your quad so that it generally slightly OVER reads so that you always 'think' you've used a little more than you actually have & to account for Internal resistance losses. If you don't have access to an accurate meter you can 'calibrate' it to what your lipo charger recharges - fly a pack, note the mAh reading, charge, note the mAh reading then adjust current calibration up/down until readings are fairly close. Note charging a battery ALWAYS adds more energy to the pack than you discharge.. This also assumes your charger is accurate which is another story XD
Funny after watching this video this question came up on my mind and I was just about to ask about it here, because that's quite often my main source of information in terms of how much battery I have left. I honestly was pretty sure this measurment is very accurate. Thanks for that advise, now I'll do some tests, especially now when I'm flyng iFlight quad. Thanks guys!
@@Filipniak yea, most FC/ESC stacks actually give you a calibration number to use in BF; but most people probably never even noticed it, and honestly for most people super accurate Current readings isn’t that important. If you do longer-range flights, and/or use Li-Ion packs, it’s always best to do some calibration checks yourself. Having an accurate number will help you avoid running out of battery, or pulling too much current & frying the battery! Note: Though Current & mAh Used figures are helpful guides, it’s also extremely important to watch Per Cell Voltage because you can judge the true health of the battery by watching the Voltage. Over time batteries get weaker & lose capacity, so if you only focus on mAh Used as a fuel gauge you might get an unpleasant surprise one day!
My friend is making his own Li-Ion packs from single 21700 battery cells that he is configuring according to his needs for his long range drone. Good thing about it is he can adjust the cell pack shape for the particular drone as he needs and also he can adjust the capacity based on how long he needs to fly...
I make my own 4S Li-Ion packs out of Murata 18650's. Slightly heavier than LiPo 4S but I can fly my 4" with a naked gopro for 25 minutes on a good day. I fly cinematic/exploration and long range so it's perfect for me. 6S Li-Ion on a 7" is absolutely bonkers, I think I got up to 40 minutes in one test flight.. with some juice to spare.
Congrats on the 300k subs, jb. 🎉 16:17 I don't quite agree with your choices. Most Li-Ion packs (4 or 6S1P) have a max discharge rate of 30-40A, depending on if they're using 18650s or 21700s. So even if you never exceed ~60% throttle, you will still hit the 30/40A rating of the battery (meaning that the battery gets hot and damaged). I've noticed that on my 7" when I when I exceed about 50% throttle the battery gets hot. Which is why I only recommend using LiIon packs on very efficient multicopters (like the Rekon line of quads) or on fixed wing aircraft
@@saturn_fpv I had issues on a rekon 6, with I3 (no GoPro) on a geprc 3000mah 6s pack with original 2blade props. I think I used the pack before about 20 times -> it could’ve been also wear …
3000mah shows it was a straight 6s1p arrangement, yes tbat is gonna be problematic. 6s2p is the minimum I would want in combination with 7in or 10inch quads. I was very impressed with a 10in using 3115 980kv motors with 6s2p. If built for a pair of 4s2p pacls in series for 8s2p the thing would have outright ripped. That is one of places I left off when I backed off of building 4 years ago
one more thing to watch out for in li-on is the Amp draw/usage.. that punch out is really brave. xD I wont ever do that to my Li-on so thanks for showing it to me.
Nice to see Bardwell touch on Li-Ion packs. I’ve been flying them exclusively on my 7” quad for years & here’s some additional thoughts: *Warning* Not a Popular Opinion, but Soldered packs perform much better than Spot Welded Packs. The reason: Welding requires the use of metals with High Resistance. Nickel is generally used, but Copper is 4x better at conducting electricity, so you get less sag & batteries stay cooler/last longer. Unfortunately all retail packs use thin nickel strips, so you’ll have to DIY to have copper packs. DIY isn’t hard but takes some basic knowledge & patience so you don’t overheat things… I’ve thought about doing a comparison but retail packs are 2x as expensive as DIY packs. For those curious; here’s a super stressful Li-ion tests in the mountains: ua-cam.com/video/gxSfD6PH1P0/v-deo.html And here’s a very detailed comparison of various li-Ion setups: ua-cam.com/video/rynkx_OYTFI/v-deo.html Definitely a great “tool in the bag!”
When soldering Li-ion cells you need to be very careful. They're particularly sensitive to heat so you need a good iron with a large tip. The surface of the cells also needs to be prepped well. I would use very high grit sandpaper (1000+) or scotch brite then immediately coat with flux. You also need to solder very quickly, not more than a couple of seconds. -HereComesWhitey ;)
Sony VTC5D seemed to be the best cell available. Gave up some capacity but gained back amperage available. Tried some larger dimention "high amp" batteries and they proved not worth it.
@@PhonesandDronesRepair hey bud, 100% accurate. Prep & Time are key. It’s usually takes my two rounds of soldering. Soldered a dozen packs and all turned out great. Glad you mentored this, people must do research and use caution. cheers!
11:30 Although the lion battery is sagging to a lower voltage, it is still less of a sag than a typical lipo if you consider the percent of the usable voltage ranges.
I had a Auline 3000mA 4S for my long range Roma L5 and I can get the 2.5 after 25 to 30 min of flight. I think Li-Ion will work different if the drone pulls less current than average 5" free style drone.
If your amp reading is somewhat right, you are pulling beyond 100A from a 2P configuration, no 18650 cell is rated at or above 50A. Long range FPV usually does not exceed those ratings so it makes way more sense there.
I maxed out my ardupilot 6" to 2.233 v/cell before bringing it down from poshold running (hover test only) for 32min. on a homemade 3s battery using 21700 lion cells.
I thought you were going to say "Well the reason it is different is this lipo is actually li-Ion" and then give a rundown of what lipo means and the different chemistries.
I agree dude, having made about four packs of 6S. I lost a quad listening to Bardwell 2.5v suggestion. (much love to Bardwell and his awesome work) The quad I lost went from 2.65v to zero in seconds. I think 3v to 2.9v is a safer landing threshold. I start coming home at about 3.35v, maybe sooner, depending on how far I've gone.
@@DFEUERMAN yea, I always try to land before 3v, I save 3-2.5v for emergencies only. (Though I have drained them right down below 2v in one of my tests. Haha!)
@@GiantAntCowboy Haha, you're lucky the FC voltage regulator was able to handle the low battery voltage. (or did the FC power off?) My quad FC shut off over a cove of water. But the quad was so beat up, I don't miss it much. ✌️🪦 I think the 2.5v max discharge spec that JB keeps mentioning is intended for very light and slow loads like an LED flashlight, not for quadcopters.
@@DFEUERMAN Yea, watch the end of this test video, ua-cam.com/video/gxSfD6PH1P0/v-deo.html I pushed it as far as it would go… was an awesome test. 🏔️The quad actually survived, but was retired after this test. I used the parts for another build. However what’s really crazy is that I still use this battery pack years later to power my goggles! Molicel P42a cells are amazing, I push them well beyond their limits often.
Totally a li-ion guy. Chill tours and and videography. But I do love a good punchy session. Hypothetically, I didn’t see fitted packs when I looked for them at the time
I have built a number of Li-ion batteries and the problem with the sag on a punch out is the thickness of the wires/connectors that are used, in your batteries case I would think it is flat metal plates spot welded to the batteries and the square area of those plates will make a difference eg. if they have used 10mm wide by 0.15 thick that equals a 1.5mm square wire. To do 20 amps the wire needs to be around 1.84 sq mm. To do 40 amps the square are is 7.9mm. Clearly difficult to achieve. If people want to build their own my recommendation is to use wires soldered to the battery not the flat plates with spot welding.
I use Li-Ion cells in my big EDF jets ;) You can compensate for the voltage drop, by adding more cells (7S instead of 6S, plus a ESC that will handle that), or getting a 15% higher KV motors.
Lastly. Charge rates. 18650s do not want to see more than a 1C charge rate, some cells even listed .5C. So if you drain a Lithium Ion expect a solid hour or more on the charger to get it back up to full voltage. Even storage is gonna take around 45 min from 2.8-3v
One is a lipo and the other a lion. You keep referring to the GepRC as a lipo I'll include two time stamps. The first 0:41 clearly shows the GepRC has 18650 and is lithium Ion as its marked Lion The second 1:53 is Bardwell making the slip of calling the lion a lipo. Its an easy slip to make and I expect later in the video this won't happen but I had already noticed this slip a few times by the 1:53 point. Prompting this note.
Why no Current/Amp Draw on the OSD? Im curious to see how many Amps this thing is pushing out during those full throttle vertical runs with the fully charged battery. It really did get up there quick and sounded as powerful as Lipo just by ear and how fast it punched up.. Im sure when the Li-ion cells get even better they will have all the advantagesbut without all the slight disadvantages vs a LiPo Battery Pack right now. Also, how is the charging time on this pack? Can it be charged at 1C or maybe even higher?
The 6000mAh Geprc pack has a maximum charge rate of 5A or 0.83C. Most of the 18650 and 21700 cells have a recommended charge rate of 1C or less. Some can go higher, but they will get very hot and should use a charger with over temperature cutoff.
In my researched opinion, FalconRad FPV has the finest methods for building quality Li-ion packs. I have been building packs for a couple years, but I wish I had seen his tutorial first. The way he lays out his balanced lead is perfect.
When I was a teen in need of money, like 10 years ago, I was making custom LI-ON battery packs like that for forum members from FPV/RC community. But then one guy crashed hard and the whole thing caught on fire and I've stopped doing this to not get myself in some legal trouble. Before that I had plane people tell me they would not need to land to change the battery anymore with my li-on battery and they could fly so long they would land because they get bored or their legs start to hurt, the flight time for planes was like 2-3x longer. I was testing those to be used for FPV quadcopters as well and the results were good for non-racing uses but then I stopped because of the above.
For low current draw ones yes. A plane that draws a lot of current - no. Same with quads. Great for long range cruising but crap for racing or freestyle.
There is a certain technique when flying li-ion packs. You want to do small smooth movements on the sticks. I've been able to fly for a good 2 miles on low voltage by keeping the throttle at a set position and making elevation changes with pitch changes. If you try to do aggressive punch outs or quick tight turns you'll just crash. It's better to do long , smooth lines with li-ion.
nope because that capacitor is able to draw massive amounts of current to recharge. i tested it. makes no difference. what would make a difference is, if you can electrically decouple the capacitor from the pack and have a small PCB onboard charger which limits the current going in the capacitor until its fully charged and same PCB will activate it ONLY on full throttle punches. but to make it useful you need to have a huge capacitor on your quad. bigger than the quad itself i think. interesting idea for sure though... 🤔👍
@@techstuff6829 Sounds like a good idea initially but in reality its not so great. Li-Ion cells should be used to a lower voltage to get the full capacity. If in parallel with a lipo then the lowest safe voltage of the lipo becomes limiting. So then you might aswell go with a higher capacity lipo.
Current draw needs to balanced with battery capacity to get the discharge c rate sensible with lion, thats all. They don't have the ability to dump the same kinds of current as lipos, at least, 18650 sized lions dont. There are some bigger lions that can, but you'll have to go back to 4s.
So, if I've understood the mechanism correctly, if I want to enjoy a cruise ride with at most a dive or a little more, without engaging in freestyle maneuvers, I could easily opt for a Lion battery instead of a LiPo even on a 2/3"? Could I also do this on a TinyWhoop for more relaxed cruising to enjoy the scenery? It really depends on what you aim to do with it (sometimes I just love cruising around to take in the views).
I wonder if there is a way to increase the current carrying capabilities to compensate for the voltage drop, but I imagine this would involve the use of some beefy capacitors given the currents we are dealing with when throttling at full power, even if only for a brief time.
Nice I will use lion in 2 scenarios: 1Long range mauntaine cruising with simple freestyle, dives, loops ets.... 2 car chase at a track Both with 7 inch What do you think about that?
thanks for another amazing video, I never even thought about how betaflight measures the cell power... THANKS for this, because until now I only displayed the cell current... :-) question: it seems you never found great lion packs, at least I cant find them in the description ? Just searching atm so... any hints would be highly appreciated !
If you are asking what kind of battery you should use to power your charger while charging lipos on the field then you should get whichever you can buy for best capacity/price ratio.
Used to be I could take a 6s2p 18650 pack out and get nearly 6-7 minutes of cruising flying out of a 7in or 10in build. 3.0v is the time to be close to home to land while 2.8 is for something wrong and you need another minute to land due to some unexpected nonsense.
Can one have both in parallel on the same drone to get a middle ground? I.e. Lipo helps with power spikes and li-ion for longer flight time... A small lipo kinda working as a large capacity capacitor?
You could but the low voltage cutoff of a lipo and liion are too far apart. With my liions I usually plan to land at 3.0V per cell, sometimes I end up a bit lower. With lipos I try to land at 3.5 or above to keep them happy. That would be a lot of unused capacity of liion side of your combobattery. Better to just go with a bigger lipo.
I find it cute that a $70 battery is "expensive". I remember the 6S 5000mah lipo batteries for my T-REX 600 RC helicopter were $300 a pop. (This was in 2008) Holy crap have battery prices come down since then.
I've been chasing drift cars this summer, and often I really don't need a lot of punch but it would be nice do double my battery capacity! Could some changes to the throttle curve help make up for the lack of punch? Just to reduce the lag a bit if I find myself in trouble so I don't smash into a car or asphalt.
My question is... Does the voltage under load count as minimum voltage? (If you punch out a lipo and falls under 3v/cell, will you damage the battery?)
As I understand it, you will damage your Lipo if it falls under ~3V period. So yes, under 3V during a punch out will damage it. At least that's what I've always heard and how I fly my packs
@@QuickNick2402 Makes sense! because you are under 3v no matter what.. but there is a debate that the recovery voltage is the most important, that's why I asked.
@@andrasfarkas6805 buuuuut dont get fooled. HV lipos are very nice when you need a lightweight battery with more capacity. but they are super fragile and i wouldnt even dream about ripping with them. they are a good alternative in between lipos and lifepo 18650 packs. but they cant handle high currents well and should be used mostly for long range or smooth cinematic flying. i used them alot in the past. their lifetime is also very limited and usually you can throw them in the trash after half summer of flying. all my HV packs puffed up several weeks after i bought them so i dont use them anymore.
i am using semi solid state packs for my electric PPG and so far they are ok but i feel more voltage sag than with a lipo pack if i try to fly high. also the battery gets extremely hot. having more capacity in a less weight and smaller pack definitely seems to have its price and it might not be the "magic battery" we all waiting for. its still nice. but from that 24s 30Ah battery i can only use around 22-23Ah maximum. over 7ah are just gone due to heat
The VTC6 cells in the pack are not high discharge 18650 li-ion. Try a true high discharge li-ion such as Molicel p28a slightly lower capacity but more than double the discharge current.
Nice video jb. What are the standard voltages for lithium ion batteries? Same as lipo? Minus discharge? For instance.. Full voltage: 4.2 and storage: 3.8? And can run them down let’s say 3.0? If you run it like that is this likely to generate reliability or is this considered abusing it?
For LiIon I land at 3.2-3.0v per cell. The last bit down to 2.8-2.5v is like emergency reserve fuel lol. On a GEPRC Mk5 with a 6S 4000mah I get 10+min landing around 3.1v
Very interesting - especially as I want to build a 7". My 6S 1000 mAh LiPos give a a battery warning after less than a minute. Are they done? Around 2 to 2.5 years old...
@@aowi7280 Great advice. How much percent do you normally drain when flying down to say 3.6 volts? I normally fly to 3.5 or 3.6 so when I disarm I'm at 3.8/storage.... Even those with the battery warning yesterday are back up to 3.8/3.9!
For those who watched this video and others, I really recommend the patreon, you will learn a lot, there are so many people who understand FPV drones there, in addition to being able to ask questions on the live stream and buy and sell products, I sold a lot there xD
I assume the reason you say that you should pick a Li-ion pack in the same weight range as the LiPo pack is to to account for the lower discharge rating of the Li-Ion? As in: If you don't need extended flight times, don't attempt to reduce weight by going with a Li-ion pack half the weight of the Li-po in an attempt to reduce the weight but keep the same mAh.
TLDW? Because useable voltage range you can use. But things get spicy on Lithium Ion when you fly below 3.2 volts. Basically better be looking to land, voltage sag is quick. 2.8v dips are right there. Parallel is needed for giving useable current. Higher series like 6s is needed to raise voltage so it helps to lower the current to a reasonable range handled by the parallel cells. Was building 6s2p on in and 10in builds 4+ years ago. Ran 6s4p on 13in Xclass. Planned next up was 8s4p for a 13in that could reasonably rip as well as something much bigger that would have been 6s8p.
IMPORTANT: Make sure to calibrate your Current Sensor. The Amp reading is often inaccurate and it’s a very important metric when using Li-Ion packs.
How accurate is accurate? Which brand of sensor is the most accurate?
@@3dxyz412 it’s impossible to get perfect because there’s a lot of variables... So I always calibrate my sensor so the Current (Amps) & mAh Used display are slightly higher than actual. This is the safest way to do it.
With a couple tries you can usually get it within 5% of actual.
Basic Process: Fully Charge a Pack, Fly/Drain it, Note the mAh Used, then Charge the pack & Note the mAh Hours Charged. The difference between the Used & Charged is what needs to be calibrated.
Oscar Liang has a good write up in the Calibration Process with the calculation used to set the amount.
Note: Also check your Voltage Readings. This is easy & usually pretty accurate, but Current (Amps) always needs to be checked & set.
@@3dxyz412 Every single quad current sensor I've measured has been noticeably out, usually ~10-20% - some worse than others (iflight ESC's especially). The answer is to calibrate your quad so that it generally slightly OVER reads so that you always 'think' you've used a little more than you actually have & to account for Internal resistance losses. If you don't have access to an accurate meter you can 'calibrate' it to what your lipo charger recharges - fly a pack, note the mAh reading, charge, note the mAh reading then adjust current calibration up/down until readings are fairly close. Note charging a battery ALWAYS adds more energy to the pack than you discharge.. This also assumes your charger is accurate which is another story XD
Funny after watching this video this question came up on my mind and I was just about to ask about it here, because that's quite often my main source of information in terms of how much battery I have left. I honestly was pretty sure this measurment is very accurate. Thanks for that advise, now I'll do some tests, especially now when I'm flyng iFlight quad. Thanks guys!
@@Filipniak yea, most FC/ESC stacks actually give you a calibration number to use in BF; but most people probably never even noticed it, and honestly for most people super accurate Current readings isn’t that important.
If you do longer-range flights, and/or use Li-Ion packs, it’s always best to do some calibration checks yourself. Having an accurate number will help you avoid running out of battery, or pulling too much current & frying the battery!
Note: Though Current & mAh Used figures are helpful guides, it’s also extremely important to watch Per Cell Voltage because you can judge the true health of the battery by watching the Voltage.
Over time batteries get weaker & lose capacity, so if you only focus on mAh Used as a fuel gauge you might get an unpleasant surprise one day!
Li-ion has been the nr.1 choice for long range rigs for years.
My friend is making his own Li-Ion packs from single 21700 battery cells that he is configuring according to his needs for his long range drone. Good thing about it is he can adjust the cell pack shape for the particular drone as he needs and also he can adjust the capacity based on how long he needs to fly...
He should make a video or post on how to do it
@@ryanisacuc8381there are hundreds of videos like that
I make my own 4S Li-Ion packs out of Murata 18650's. Slightly heavier than LiPo 4S but I can fly my 4" with a naked gopro for 25 minutes on a good day. I fly cinematic/exploration and long range so it's perfect for me. 6S Li-Ion on a 7" is absolutely bonkers, I think I got up to 40 minutes in one test flight.. with some juice to spare.
Congrats on the 300k subs, jb. 🎉
16:17 I don't quite agree with your choices. Most Li-Ion packs (4 or 6S1P) have a max discharge rate of 30-40A, depending on if they're using 18650s or 21700s. So even if you never exceed ~60% throttle, you will still hit the 30/40A rating of the battery (meaning that the battery gets hot and damaged).
I've noticed that on my 7" when I when I exceed about 50% throttle the battery gets hot. Which is why I only recommend using LiIon packs on very efficient multicopters (like the Rekon line of quads) or on fixed wing aircraft
A “popped” one about a year ago, be careful 😉
8s FTW
@MJ-bj1gn This is a 2P pack, that's why double the amp draw is possible.
@@saturn_fpv I had issues on a rekon 6, with I3 (no GoPro) on a geprc 3000mah 6s pack with original 2blade props. I think I used the pack before about 20 times -> it could’ve been also wear …
3000mah shows it was a straight 6s1p arrangement, yes tbat is gonna be problematic. 6s2p is the minimum I would want in combination with 7in or 10inch quads. I was very impressed with a 10in using 3115 980kv motors with 6s2p.
If built for a pair of 4s2p pacls in series for 8s2p the thing would have outright ripped. That is one of places I left off when I backed off of building 4 years ago
I fly the same GEPRC 6000mAh Li-Ion packs with my Chimera 7 V1 & V2 quads. They're great for long range cruising. They get me up mountains.
one more thing to watch out for in li-on is the Amp draw/usage.. that punch out is really brave. xD I wont ever do that to my Li-on so thanks for showing it to me.
Tanks to Joshua, now we know the complete layout of his home. ;)
Nice to see Bardwell touch on Li-Ion packs. I’ve been flying them exclusively on my 7” quad for years & here’s some additional thoughts:
*Warning* Not a Popular Opinion, but Soldered packs perform much better than Spot Welded Packs. The reason: Welding requires the use of metals with High Resistance. Nickel is generally used, but Copper is 4x better at conducting electricity, so you get less sag & batteries stay cooler/last longer.
Unfortunately all retail packs use thin nickel strips, so you’ll have to DIY to have copper packs. DIY isn’t hard but takes some basic knowledge & patience so you don’t overheat things…
I’ve thought about doing a comparison but retail packs are 2x as expensive as DIY packs.
For those curious; here’s a super stressful Li-ion tests in the mountains:
ua-cam.com/video/gxSfD6PH1P0/v-deo.html
And here’s a very detailed comparison of various li-Ion setups:
ua-cam.com/video/rynkx_OYTFI/v-deo.html
Definitely a great “tool in the bag!”
When soldering Li-ion cells you need to be very careful. They're particularly sensitive to heat so you need a good iron with a large tip. The surface of the cells also needs to be prepped well. I would use very high grit sandpaper (1000+) or scotch brite then immediately coat with flux. You also need to solder very quickly, not more than a couple of seconds.
-HereComesWhitey ;)
Sony VTC5D seemed to be the best cell available. Gave up some capacity but gained back amperage available. Tried some larger dimention "high amp" batteries and they proved not worth it.
@@dividingbyzerofpv6748 my favorites are Molicel, especially the P28a for 18650, or P45b for 21700.
Have you tried these?
@@PhonesandDronesRepair hey bud, 100% accurate. Prep & Time are key. It’s usually takes my two rounds of soldering. Soldered a dozen packs and all turned out great.
Glad you mentored this, people must do research and use caution. cheers!
at what voltage do you land your drone? I have a pair of ion packs but i'm still landing them at 3.3v
Thank you for signing that battery, Man 🥰🗽
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11:30
Although the lion battery is sagging to a lower voltage, it is still less of a sag than a typical lipo if you consider the percent of the usable voltage ranges.
You're a brave man. I won't even punch out my 6" on molicel 6S packs. It's not hard at all to hit 60-70 amps
I had a Auline 3000mA 4S for my long range Roma L5 and I can get the 2.5 after 25 to 30 min of flight. I think Li-Ion will work different if the drone pulls less current than average 5" free style drone.
I have those in 6S they are very good.
Alright! I'm gonna learn something today!
As someone new to flying fpv even though I've had it for a few years this is my kind if battery. Just want to cruise and learn some cinematic videos
If your amp reading is somewhat right, you are pulling beyond 100A from a 2P configuration, no 18650 cell is rated at or above 50A. Long range FPV usually does not exceed those ratings so it makes way more sense there.
They seem like great packs for indoor tours with real estate
AWESOME AWARD granted!
Best explanation of the difference I have ever seen. Thanks!
My first and second builds were based on liIon batteries. But have since moved to lipo packs
Could've included amp draw on osd after calibration to get an idea of c rate.
I really like this guy because he knows what expensive is .
Hey Joshua can you do a video on the logic fpv sim, it’s the realest one out
just gonna throw this out there, for DIY packs, the Molicel P28a 18650 li-ion are great. max continuous discharge rate of 35a!
yes 👍🏻… or for bigger packs the Molicel P45B 21700 cells with 4500mAh and 45A continuous discharge
@@KitePodexcept p45b is like $9 per cell, & for drones prolly won't work in 1p.
Not just great, they’re the best!
I maxed out my ardupilot 6" to 2.233 v/cell before bringing it down from poshold running (hover test only) for 32min. on a homemade 3s battery using 21700 lion cells.
Now test a LiFePo4 for the funsies!
Generally a comparison of energy density (Wh/kg) and C discharge rating comparison would be so nice!
did you mean to call the liion pack lipo up until 2:50?
I thought you were going to say "Well the reason it is different is this lipo is actually li-Ion" and then give a rundown of what lipo means and the different chemistries.
Ive noticed once you drop below 3volts it starts dropping a lot faster. I try to land around 3v per cell or just below it on lion
Yea agreed. I’ve found that once it’s at 3v per cell you’ve used 90% of the pack & from there it’s drops very quick.
I agree dude, having made about four packs of 6S. I lost a quad listening to Bardwell 2.5v suggestion. (much love to Bardwell and his awesome work) The quad I lost went from 2.65v to zero in seconds. I think 3v to 2.9v is a safer landing threshold. I start coming home at about 3.35v, maybe sooner, depending on how far I've gone.
@@DFEUERMAN yea, I always try to land before 3v, I save 3-2.5v for emergencies only. (Though I have drained them right down below 2v in one of my tests. Haha!)
@@GiantAntCowboy Haha, you're lucky the FC voltage regulator was able to handle the low battery voltage. (or did the FC power off?) My quad FC shut off over a cove of water. But the quad was so beat up, I don't miss it much. ✌️🪦
I think the 2.5v max discharge spec that JB keeps mentioning is intended for very light and slow loads like an LED flashlight, not for quadcopters.
@@DFEUERMAN Yea, watch the end of this test video, ua-cam.com/video/gxSfD6PH1P0/v-deo.html
I pushed it as far as it would go… was an awesome test. 🏔️The quad actually survived, but was retired after this test. I used the parts for another build. However what’s really crazy is that I still use this battery pack years later to power my goggles!
Molicel P42a cells are amazing, I push them well beyond their limits often.
Totally a li-ion guy. Chill tours and and videography. But I do love a good punchy session. Hypothetically, I didn’t see fitted packs when I looked for them at the time
Awesome flying and review, Joshua! 😃
Thanks for all the info!
Stay safe there with your family! 🖖😊
I’m convinced that Bardwell never ages 🎉 been watching for years! Keep up the good work man 😎
Can't say the same for that wooden gate structure.
I have built a number of Li-ion batteries and the problem with the sag on a punch out is the thickness of the wires/connectors that are used, in your batteries case I would think it is flat metal plates spot welded to the batteries and the square area of those plates will make a difference eg. if they have used 10mm wide by 0.15 thick that equals a 1.5mm square wire. To do 20 amps the wire needs to be around 1.84 sq mm. To do 40 amps the square are is 7.9mm. Clearly difficult to achieve. If people want to build their own my recommendation is to use wires soldered to the battery not the flat plates with spot welding.
Another option is copper sheet spot welded with nickel on the terminals. Copper is over 4x as conductive as the usual nickel strip used.
Only battery I have ever go PUFFY was one of these. So much for the safe ones
I use Li-Ion cells in my big EDF jets ;)
You can compensate for the voltage drop, by adding more cells (7S instead of 6S, plus a ESC that will handle that), or getting a 15% higher KV motors.
Lastly.
Charge rates. 18650s do not want to see more than a 1C charge rate, some cells even listed .5C. So if you drain a Lithium Ion expect a solid hour or more on the charger to get it back up to full voltage. Even storage is gonna take around 45 min from 2.8-3v
You need to place an OSD amp meter and the throttle stick overlay so we can see what is going on the way you are experiencing it.
This is goldmine. Ty
One is a lipo and the other a lion. You keep referring to the GepRC as a lipo I'll include two time stamps.
The first 0:41 clearly shows the GepRC has 18650 and is lithium Ion as its marked Lion
The second 1:53 is Bardwell making the slip of calling the lion a lipo.
Its an easy slip to make and I expect later in the video this won't happen but I had already noticed this slip a few times by the 1:53 point. Prompting this note.
Indeed. I kept going back to the biginning out of confusion.
Why no Current/Amp Draw on the OSD? Im curious to see how many Amps this thing is pushing out during those full throttle vertical runs with the fully charged battery. It really did get up there quick and sounded as powerful as Lipo just by ear and how fast it punched up..
Im sure when the Li-ion cells get even better they will have all the advantagesbut without all the slight disadvantages vs a LiPo Battery Pack right now.
Also, how is the charging time on this pack? Can it be charged at 1C or maybe even higher?
The 6000mAh Geprc pack has a maximum charge rate of 5A or 0.83C.
Most of the 18650 and 21700 cells have a recommended charge rate of 1C or less. Some can go higher, but they will get very hot and should use a charger with over temperature cutoff.
Ah, this must be the reason why DJI Avata has twice the battery efficiency than DJI FPV drone. Great to finally understand it, thanks JB!
Thanks so much for all your help . Your a hard working very helpful knowledgeable decent caring son of a gun so 👍 Thanks .
In my researched opinion, FalconRad FPV has the finest methods for building quality Li-ion packs. I have been building packs for a couple years, but I wish I had seen his tutorial first. The way he lays out his balanced lead is perfect.
appreciate it thanks a lot!
Congrats for 300K
Omg you are alive! 😂
Well, he said he will be on a road trip and would not upload for some time. No surprise.
Listen someone has to give the man trouble. I know I was just joking around@@musicvr3368
When I was a teen in need of money, like 10 years ago, I was making custom LI-ON battery packs like that for forum members from FPV/RC community.
But then one guy crashed hard and the whole thing caught on fire and I've stopped doing this to not get myself in some legal trouble.
Before that I had plane people tell me they would not need to land to change the battery anymore with my li-on battery and they could fly so long they would land because they get bored or their legs start to hurt, the flight time for planes was like 2-3x longer.
I was testing those to be used for FPV quadcopters as well and the results were good for non-racing uses but then I stopped because of the above.
UpgradeEnergy makes great Li-ions for long range, check out the Dark Lithium or the Botgrinder LongRange Batt
Great stuff!
Great vid Cheers
I tried running li ions in my SJRC drone but the metal casings interfered with the compass
Great info man!! Li-ion seems like it could be good for fixed wing aircrafts. Throughs?
For sure, I get over an hr flight time with a 4s 5000 mah li-ion pack 21700 cells on a Nano Talon Evo
I got a 2P4S pack in my 2.4m wingspan plane and it works great
@@dronepilot260rc where’d you buy one of these from?
For low current draw ones yes. A plane that draws a lot of current - no. Same with quads. Great for long range cruising but crap for racing or freestyle.
@@rehepeks awesome. Thank you for the reply!
There is a certain technique when flying li-ion packs. You want to do small smooth movements on the sticks. I've been able to fly for a good 2 miles on low voltage by keeping the throttle at a set position and making elevation changes with pitch changes. If you try to do aggressive punch outs or quick tight turns you'll just crash. It's better to do long , smooth lines with li-ion.
"this area under the curve" I got ptsd for a moment. Im still taking my engineering course and I heard something way too familiar
Thx
I am using the home made 21700 lion pack on a 7 inch tricopter.
It is cooll :D
If you are gentle it can fly
Do you think a large capacitor could be added to the pack? To help with sudden high amp needs. Like, with punch out or recoveries.
nope because that capacitor is able to draw massive amounts of current to recharge. i tested it. makes no difference. what would make a difference is, if you can electrically decouple the capacitor from the pack and have a small PCB onboard charger which limits the current going in the capacitor until its fully charged and same PCB will activate it ONLY on full throttle punches. but to make it useful you need to have a huge capacitor on your quad. bigger than the quad itself i think. interesting idea for sure though... 🤔👍
There was a guy that made a combo pack with both LiPo for punch and Li-Ion for capacity.
@@techstuff6829 Sounds like a good idea initially but in reality its not so great. Li-Ion cells should be used to a lower voltage to get the full capacity. If in parallel with a lipo then the lowest safe voltage of the lipo becomes limiting. So then you might aswell go with a higher capacity lipo.
Current draw needs to balanced with battery capacity to get the discharge c rate sensible with lion, thats all. They don't have the ability to dump the same kinds of current as lipos, at least, 18650 sized lions dont. There are some bigger lions that can, but you'll have to go back to 4s.
So, LIon is better for fixed wings? Lower power output for longer duration.
So, if I've understood the mechanism correctly, if I want to enjoy a cruise ride with at most a dive or a little more, without engaging in freestyle maneuvers, I could easily opt for a Lion battery instead of a LiPo even on a 2/3"?
Could I also do this on a TinyWhoop for more relaxed cruising to enjoy the scenery?
It really depends on what you aim to do with it (sometimes I just love cruising around to take in the views).
JB really loving his goggles 2
I think that the v2 are better...
0:04 you mean 6000mah lithium ion????
Have like 50 lishen 21700 cells left from building my ebike pack ,definitely gonna build a few packs
JB... your first two LiIon links go to the same place.
Paaawww to the moon lol
I can concur with your results
Finally the video I needed.
I wonder if there is a way to increase the current carrying capabilities to compensate for the voltage drop, but I imagine this would involve the use of some beefy capacitors given the currents we are dealing with when throttling at full power, even if only for a brief time.
There are a lot of built in safety features (and weight) of the cylindrical cells
What Drone is that Josh?
I charged up my lithium pack for my GEPRC Croc 5 today and just wondered about this.
Why aren't there esc's that also take measurements from the balance lead?
Nice
I will use lion in 2 scenarios:
1Long range mauntaine cruising with simple freestyle, dives, loops ets....
2 car chase at a track
Both with 7 inch
What do you think about that?
thanks for another amazing video, I never even thought about how betaflight measures the cell power... THANKS for this, because until now I only displayed the cell current... :-)
question: it seems you never found great lion packs, at least I cant find them in the description ?
Just searching atm so... any hints would be highly appreciated !
Maybe some light weight super capacitors could give you the big punches on demand with the 18650s?
Should we use li-po or li-ion to charge lipo on the field ?
LiPo. It's fine to charge them to 4.2 and that is the intended use.
If you are asking what kind of battery you should use to power your charger while charging lipos on the field then you should get whichever you can buy for best capacity/price ratio.
@@rehepeks thanks bro
Hello! As always Thank you for your content. Do you think i can use this in my protek 60 cinelifter?
I don’t think he is gonna respond to that
Used to be I could take a 6s2p 18650 pack out and get nearly 6-7 minutes of cruising flying out of a 7in or 10in build. 3.0v is the time to be close to home to land while 2.8 is for something wrong and you need another minute to land due to some unexpected nonsense.
Where do you get those black rubber bands?
Can one have both in parallel on the same drone to get a middle ground? I.e. Lipo helps with power spikes and li-ion for longer flight time... A small lipo kinda working as a large capacity capacitor?
You could but the low voltage cutoff of a lipo and liion are too far apart. With my liions I usually plan to land at 3.0V per cell, sometimes I end up a bit lower. With lipos I try to land at 3.5 or above to keep them happy. That would be a lot of unused capacity of liion side of your combobattery. Better to just go with a bigger lipo.
What if you put capacitors between the motors & the esc????
I reckon the motor won't spin.
I find it cute that a $70 battery is "expensive". I remember the 6S 5000mah lipo batteries for my T-REX 600 RC helicopter were $300 a pop. (This was in 2008) Holy crap have battery prices come down since then.
I've been chasing drift cars this summer, and often I really don't need a lot of punch but it would be nice do double my battery capacity! Could some changes to the throttle curve help make up for the lack of punch? Just to reduce the lag a bit if I find myself in trouble so I don't smash into a car or asphalt.
My question is... Does the voltage under load count as minimum voltage? (If you punch out a lipo and falls under 3v/cell, will you damage the battery?)
As I understand it, you will damage your Lipo if it falls under ~3V period. So yes, under 3V during a punch out will damage it. At least that's what I've always heard and how I fly my packs
3v is very low for a LIPO. I stop at 3.6 I think or 3.5v per cell average
The rebound voltage after sitting is the important number.
@@QuickNick2402 Makes sense! because you are under 3v no matter what.. but there is a debate that the recovery voltage is the most important, that's why I asked.
This is really interesting how would these 2 batteries compare to a graphene battery in performance
And whats with LiHv?
Whats the discharge Voltage from these batterys?
same as a normal Lipo, HV just charges to 4.35V
It's a lipo
Ok thanks
@@andrasfarkas6805 buuuuut dont get fooled. HV lipos are very nice when you need a lightweight battery with more capacity. but they are super fragile and i wouldnt even dream about ripping with them. they are a good alternative in between lipos and lifepo 18650 packs. but they cant handle high currents well and should be used mostly for long range or smooth cinematic flying. i used them alot in the past. their lifetime is also very limited and usually you can throw them in the trash after half summer of flying. all my HV packs puffed up several weeks after i bought them so i dont use them anymore.
What foam do you use for these DJI goggles 2?
waiting for solid state ........ I think its going to change the game a bit
will solid state batteries ever make it to drone technology?
Have to be available for any consumer technologies first.
i am using semi solid state packs for my electric PPG and so far they are ok but i feel more voltage sag than with a lipo pack if i try to fly high. also the battery gets extremely hot. having more capacity in a less weight and smaller pack definitely seems to have its price and it might not be the "magic battery" we all waiting for. its still nice. but from that 24s 30Ah battery i can only use around 22-23Ah maximum. over 7ah are just gone due to heat
Racequadrones link is wrong Joshua!
The VTC6 cells in the pack are not high discharge 18650 li-ion. Try a true high discharge li-ion such as Molicel p28a slightly lower capacity but more than double the discharge current.
Shorter life but burn beautifully.
So. For long range use 18650 or 21700 cells.. And keep it low on the throttle (no punching if not needed).. They are not build for the current..
Nice video jb. What are the standard voltages for lithium ion batteries? Same as lipo? Minus discharge? For instance.. Full voltage: 4.2 and storage: 3.8? And can run them down let’s say 3.0? If you run it like that is this likely to generate reliability or is this considered abusing it?
For LiIon I land at 3.2-3.0v per cell. The last bit down to 2.8-2.5v is like emergency reserve fuel lol.
On a GEPRC Mk5 with a 6S 4000mah I get 10+min landing around 3.1v
need that avatar hd goggles x video!!!
I find it so weird that there is no goggles X review out yet. He hasn't even mentioned it anywhere.
@@nuddin99 it is very strange
Very interesting - especially as I want to build a 7".
My 6S 1000 mAh LiPos give a a battery warning after less than a minute. Are they done? Around 2 to 2.5 years old...
Probably. See how many mAh you get out (or put back in). It will get less with time.
Even if your lipos were properly stored and not abused while flying, they honestly don't last much longer than 2 years.
@@aowi7280 Great advice. How much percent do you normally drain when flying down to say 3.6 volts? I normally fly to 3.5 or 3.6 so when I disarm I'm at 3.8/storage.... Even those with the battery warning yesterday are back up to 3.8/3.9!
@@overdosed51 Thanks, I'll keep that in mind and check more before flying at a "serious" spot like cliffs...
For those who watched this video and others, I really recommend the patreon, you will learn a lot, there are so many people who understand FPV drones there, in addition to being able to ask questions on the live stream and buy and sell products, I sold a lot there xD
Not needed thanks.
I assume the reason you say that you should pick a Li-ion pack in the same weight range as the LiPo pack is to to account for the lower discharge rating of the Li-Ion? As in: If you don't need extended flight times, don't attempt to reduce weight by going with a Li-ion pack half the weight of the Li-po in an attempt to reduce the weight but keep the same mAh.
what about a 3500mah lithuim, would it be half the weight, how would it fly?
From the rotor riot starter kits, which quad would you recommend? Mk3, moxy, tanq
Tanq for its durability.
TLDW? Because useable voltage range you can use.
But things get spicy on Lithium Ion when you fly below 3.2 volts. Basically better be looking to land, voltage sag is quick. 2.8v dips are right there. Parallel is needed for giving useable current. Higher series like 6s is needed to raise voltage so it helps to lower the current to a reasonable range handled by the parallel cells.
Was building 6s2p on in and 10in builds 4+ years ago. Ran 6s4p on 13in Xclass.
Planned next up was 8s4p for a 13in that could reasonably rip as well as something much bigger that would have been 6s8p.
Basically the Li-ion cell has a lower C rating than that of the Lipo, That's why there was voltage drop.
Actually lion packs are typically more prone to “pop” under load/high amp voltage. I had this happen to me once…