Have you done discharing one by one?
No, but they wonât balance themselves while discharging, so I would expect one of the cells to become unbalanced while discharging if it had less capacity. Since I didnât see that, I should be able to assume they are pretty close. None of the cells ever got warm to the touch even. (because they never ran at 20 amp per cell for very long)
I also ran them through 10s for a few cycles as the âspace cellâ and I had a lot of sagging.
So your problem can be you may have a dead cell or it charges wrong etc. If I were you I would charge all the battery one at the time and then discharge 1 by 1. I hope you havenât the welded them together 
EDIT: Or not, it might be the brand you have, they are unknown!
I am not saying that you lie. I simply think it is wrong to compare lipos and li-ion in percent by a baseline that you define. But anyway, lets sumarize the facts.
As far as i can remember your board is setup to 65 km/h max speed, for a 220 pounds rider in san francisco with the steepest hills and 4 hummie hubs with a average total consumption of 50Wh a km. You donât continue to ride when the board dosnât bring full performance anymore.
All those values are extreme (no offence to your weight). So i think it is wrong to say that this is the raw model of a board. This board really needs the most power it can get and in your case i understand to go with lipos. But many people here are absolutely fine with a normal board and they would have no issues with a li-ion battery. And you set the baseline where you think the voltage sag is not except-able anymore. But that is not where the limit of the battery is by the specs.
Next thing is that you didnât mention this as a problem for your board before the Raptor 2 came out. Could be coincidence but feels a bit strange to me.
But you are right that the lipos have less voltage sag as li-ion. But i say that this isnât a problem as long as you donât push everything to the extreme limits. And if you have for example a 10S4P and set your battery max amps for each VESC to 30A (60A total) for a board that is setup to 45 km/h you will barely notice a difference between lipo and li-ion cells. The top speed might be 1 mile less but thatâs mostly it.
I had mentioned in my thread that I had issues with voltage sag way before the raptor 2.
I also created a thread with a pole asking users how much sag they had, mentioning sag was a big issue for me.
I have mentioned sag long before it but it was just recently I finally had the money and time (due to the costs of college) to try lipos on this setup.
I donât stop also when I get to were the performance degrades. I just consider that an issue for me.
Maybe many wonât have these issues that I have, I do do things on the bleeding edge. But what you can know then is that anything I produce has high standards of performance, under the most extreme of conditions 
One way to counter that is to use more cells in series, thatâs what boosted done in their extended range pack, if Iâm not mistaken it will be 13S2P, so even if the cells sag you wonât loose top speed or significant power, itâs basically to have a 10S board that has 25km/h top speed with the cells almost empty, so you limit the top speed to 25 and the rider will not notice the performance reduction
Some day i have to try a board with 65 km/h. Really curious how that feels. The difference from 45 to 50 is already like from fast but i can handle that to fuck that is fast and donât do a mistake now. But 15 km/h more must be quite impressive and scary. I think i will try next summer. But then with motorcycle leather gear.
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This doesnât make any sense. Why would voltage sage under max load shorten your range? You shouldnât be pulling max amps all the time, so you should also not see sag all the time. Now if you are riding only uphill and weigh 200kg, then youâre a special case and should be treated as such.
I totally agree with @evoheyax I started with 12s Lipo 5000/ 25c 125a continuous They where ok. Then I tried Li-ions 10s 9000mah 60a continuous I was very disappointed. 40% sag going up 10% grade. Ok on flat ground with light wind. Then I built an other Lipo system 10s 5000/60c 300a continuous. Now I can power up that 10% grade and my total pack voltage only sags 1 volt. Range also improves as sag is decreased. I learned this truth the hard way, you just canât have too much battery! So if you want to eliminate voltage sag, I recommend a battery thatâs capable of 10 times the current your pulling. It not easy to do this with Li-ions. Youâll need a lot of cells. Lipos offer the most power per pound and are safe enough if you treat them with respect. Btw, my batteries donât even get warm pulling my 190lbs up hills.
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Still doesnât make sense that a 10S 9000mah battery should have less range then a 10S 5000 mAh battery. What where the voltage cutoff start and end on both setups?
Itâs simple. The closer your amp draw is to the battery limit, the more itâs voltage sags, The more its voltage sags, the more amps you need to maintain power. The more amps you draw the faster your battery depletes. As your battery depletes, its voltage gets lower compounding the problem. Itâs a vicious cycle.
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Even on flat ground, I sag a decent bit and on slight up hills, I sag pretty bad. I have very little flat ground anywheres to ride on. San Francisco in the sunset district is almost exclusively hills. Probably under 10% of the roads here are flat or under 2% grade of steepness. This means Iâm always sagging pretty heavily. So when I get my cells down to 3.6v, I must stop. If I have steeper hills to tackle, I must tackle them before I hit 3.8v or Iâll sag down past 3.2v per cell. In effect, Iâm losing about 30% of my range due to sag. Now with high discharge lipos, I can get my cells down to 3.3v before I sag before the cutoff. The effect is most range. I know Iâm over simplifying this, but my real world tests with lipos and with liion showed me that a 12s 10 Ah li-ion got 6 miles of range while a 12s 8 Ah lipo got 8 miles of range. This is one of the reasons why I nag so much about sag. It slightly dampens performance (which may not be a big deal to some, it should be if your buying the quote un quote âmost powerfulâ direct drive board IMO), but also reduces range, as you must stop at a higher voltage. With the VESC, this will just mean I canât climb the hills I need to climb when my battery is suppose to have 50% left, as my voltage cutoff will start to kickin. Even with 25% of my lipo left, I can climb the hills I need to without sagging below 3.2.
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Thatâs not correct sorry. Because watts is voltage multiplied by amps. So the power drawn from the battery is still the same. As long as you donât reach maximum duty cycle the motor doesnât care where the watts he needs come from. But more amps is also more heat so you might loose a bit but 80 % (5000 compared to 9000) is beyond my imagination. Expecially when you take into account that the voltage difference is only 15 %. So at a full charge under 80A load you need 15% more amps for the same power. But this is only for the short moments when you draw max amps. To me it sounds that your cells had issues.
With li-ion you can go down to 3V or even 2.8V as cutoff. I set mine to 2.66 for example. With lipos a cutoff at 3.2V is already very low. So this is of course a explanation for the range difference. And you donât need to worry about the cutoff. Because it doesnât switch off the board. It starts to reduce the power until it reaches that level. So the vesc helps you to stay in the range you have set as cutoff end. That means it starts to reduce the power when it reaches the cutoff start and doesnât give any power anymore when it reaches the cutoff end. With a lipos you can get the feeling that it shuts off if you go as low as 3.2V. Because the lipos cells collapse at that low voltage already. Should mean when you reach that voltage under load it is OK. But when you reach that voltage without load then they can jump from 3.4V to like 3.0V in a couple of seconds. Of course that also depends on the lipos. So you need to set different cutoff start and cutoff ends for a lipo and a li-ion battery. That is also the reason why I said that you canât compare the voltage sag in % if you have the same cutoff start and end.
I tested my Li-ion pack 10s 9000mah on flat ground and got 27 miles Then I tested it on a a road with long hills and only got 10 miles. My 12s 5000/25 would go 12 miles on flat or hills. My 10s 5000/60 went 13 miles with using it up. Iâm not just throwing theory out there. Like I said, I learned this the hard way and have proved it myself.
I can see your concern, which is why I said Iâm oversimplifying it. The discharge curves of lipos vs li-ion are different and thus, it screws any data immediately. But what I also said is from real world testing, this was the case. I knew my limit with the 18650s very well, and with the lipo, I got 2 miles more past that limit.
By the way when you set the cutoff for the Samsung 25R to 3.2V the you only use 40% of the capacity under 20A load.
@Namasaki what were your cutoff levels with li-ion and lipos?
My BMS cutoff was set at 2.8v so if any cell hit that, the BMS would shut down. I ran the Li-ion pack till the BMS shut down. But really, I see your having trouble believing our report even though we have tested and proven what where saying. So the best solution if you want the truth is to go build different types of battery systems like @evoheyax and I have and prove it to yourself.
Doesnât make sense to me. The 12S 5Ah battery has the same range on flat or hills. The 10S 5AH battery goes further than the 12S battery. And the li-ion does great on flats but fails on hills with 80% more capacity. I am confused now. One last question. What li-ion cells where that? And I hope you donât use the same bms for the lipos.
This is how voltage sag affects range. More load = more sag More sag = less range. I did not use a BMS on my 12s Lipos. I monitored Voltage. Iâm using the same BMS on my 10s Lipos but monitoring voltage and not depending on BMS cutoff. My stoping point with 12s Lipo was normally 42v Which usually got me around 12 miles The 10s Lipo, I have not yet gone below 36v and have not had a chance to finish testing it however, I did get 13 miles with the battery still above nominal voltage. The Li-ion cells I tested where Basen black 26650âs 4500mah 30a continuous in a 10s 2p pack.