Preeeeeeetty worried that I seriously fucked up my pack

So I was totally new to DIY when I built my board. I should’ve done more research, because I fucked up bad. So, after a good amount of trial and error I got my board mechanically sound. However, it turns out that my VESC settings would be the next issue I would discover. My dumbass thought that the VESC would somehow be able to automatically determine the discharge rate of my pack, and left the default discharge settings where they were at. Which was 99A per motor. On my 12s4p 30Q pack. Thank god this didn’t end in catastrophe, considering my board is still all in one piece and never caught fire.

I found out these settings were fucked beyond belief months ago and set them to much more appropriate settings with the advice of someone on here (25A max discharge, -16A max charge) and they’ve been at those new settings ever since. I’m concerned that the settings being at the defaults have done long term damage to the pack though. Thankfully because it took me awhile to fix misc mechanical problems with the board I don’t think I did much more than 100 miles or so with the default settings. I rode my DIY the other day (it has 110mm TB wheels on it) until it started sagging pretty hard, and I got 14.4 miles. According to Xmatic, I consumed 314.3 watt hours with a board efficiency of 21.8 miles. Keep in mind, it’s still at the default battery cutoff settings. Did I get out mostly unscathed? Should I change my cutoff settings from the defaults? I’d definitely like to get 20ish miles, but I’m concerned that my stupidity messed up the pack.

For others reading this, 313.4Wh / (3.7V x 12) = 7.06Ah, so OP is only getting 7/12 of the expected range from his pack.

Yeah, sounds like either you damaged the cells enough that their capacity is now fucked (I kinda doubt it), or perhaps you have a dead p-group which is causing the battery voltage to drop below the cutoff prematurely. Or you’re not charging it fully :stuck_out_tongue:

I suggest you:

  1. Check in vesc settings that your battery cutoff is correct for 12s. (Absolute min should be about 37.2V)
  2. Measure the voltage of each parallel group in your battery with a voltmeter. Easy way to do this is through the balance connector. Maybe you will spot that 1 group has a totally different voltage from the rest, indicating that that group is probably dead and needs replacing.

It’s not as simple as this a lot more comes In to play you would never draw 198A what was the motor max set to?

The norm is to treat Q30 as 20a cells so in a 4p that’s 80A /2 VESC 40A eatch

Regen is 4A x 4P = 16A. Doubled because of duty cycle 32A /2vesc =16A

Dose the batery get warm do you have telemity to see voltsag and wattages used.

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you’d have to be doing some kind of insane mountain at high speed to get anywhere close to 200 amps output from the battery. even if you did hit 200 amps, which i highly doubt you did, it would likey be for a second or two. what were you doing? here theyre doing what would be 80amps continuous. Test of Samsung INR18650-30Q 3000mAh (Pink) (


Not how battery’s work you only get 3ah per cell if you pull a Tiny load and have the cut off at 2.5v.

Higher loads, age, voltsag and higher cut off will impact on Wh on even the healthiest of cells


as he says and the link i posted shows you’ll get just over 2ah a cell at 20amp continuous output.

even if your settings are off the roof the actual battery output for most people…im guessing even with lots of hard accelerating and 30mph moments youre likley only doing maybe 20-50amps.


Yeah I have telemetry, and my motor max was set to 55A usually, I was testing diff motor max settings

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Then no your extreamly unlike to have pulled enough amps for a sustain period at max speed to do any significant damage

2x55 is 110a and that can only be pulled at max duty cycle (top speed)

So what’s you efficiency Wh per km or Mile

314.3wh / 14.4miles =21.8 W per mile



In my opinion, you have big, good battery that able to push human forvard. Yes, you messed up settings for battwry drow. But but did you used 99A per motor? I really doubt it. Alltogeather its 200a on 12s, its more than 8kw of power. Its not possible to use such reallistically. Your pack can deliver 80a tgeoretically, and its plenty, i doubt you excided that. Its my opinion, but i dont think you damaged battery this way.

Cut off in other hand is much more inportant in your situation. Did you ever fully discharged your board? Was was the value of cut off at that moment?


Any thread suggestions to read more about setting up new vescs?

True, my bad.

Judging by Mooch’s 30Q discharge graphs, at 15A current draw the average voltage is 3.4V (from 3.7V to 3.1V) and lasts for about 2.1Ah. So in the 12s4p pack we’d expect ~343Ah. Without seeing logs I’m not sure if OP is even discharging that much, but hey, maybe they are and it’s normal behaviour then.

so many factors apply I just use the forums calculator.

from experience 12s4p15miles is the lower end of the more aggressive riders but about right.

20 miles is over optimistic for even some of the super light and gentle riders.

id predict you need 6p q30 to get over 20miles or look at larger cells like the molicel P42A

I used to have a 12s4p 30Q pack so im speaking from experience here when i say that a pack like that will take some serious abuse before you cause long term damage.

Firstly, just cause you put the settings high doesn’t mean you actually used that much power. That pack is capable of peak output around 4kW, which is much more than most would use who are new to esk8.

Secondly, a 4p 30Q pack is mostly self limiting in the amount of power it will give you. if you have it set to 200A battery current, weigh a fuckton, and floor it of the line, then that 4p pack will only give you around 120A before sagging from full charge down to the low voltage limits (ask me how i know).

And i rode my AT board aggressively like this for over 1000 miles before i started to see any noticeable degradation in the range. The pack is around 500Wh but not all of that is usable, realistically i used to see around 380-420wh used going full to empty on that pack, depending on ride style.

Originally used to get around 10 miles on a charge (on AT wheels) and would expect you to get a little more with thane.

if your loosing that much of your pack range i would question if there’s some sort of balancing isue with your pack, but i doubt your riding it with high current settings are the cause. and i expect its fixable :grin:


My cutoff is set at the VESC 12S default of:

Cutoff start: 40.80V
Cutoff end: 36.00V