So while I was doing uploading VESC firmware and motor configuration the motor slipped from my hand and hit one of my 4s 5000mAh batteries and damaged it pretty bad so i decided to save what I can from it. I took some pictures along the way: Basically i opened up the Battery and found that only 1 cell was damaged so i cut it out and soldered the negative lead onto the next cell in line so now i have a 3S and a 4S so my question is can i connected them in series(both being different voltage) without getting into problems down the road? I put hot glue on the exposed part of the cell(I should’ve done this at the beginning) because i noticed that the smallest movement caused sparks. I was lucky enough it didn’t catch on fire at any point.
In conclusion never test a big motor if its not secure NEVER HOLD IN HAND!!!


Since they’re the same capacity, it should be fine. You’re not supposed to mix batteries with different capacities. I think you wont be able to charge them in parallel, only in series (depending on your charger) or separately. Can someone else chime in here to confirm?

Wow thats some good damage there! If you have removed the damaged cell you shold be fine… but put that cell in a pit somewhere before it goes up! Lol. You now just have a 7S instead of an 8S.

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you can post photos directly into the forum, just drag them into the post. If you are using a mobile phone you can also upload, just get the browser to load the desktop version of this website.

good to know about the batteries. Here’s a picture of what it did to the chair

U sure the little lady didn’t fling it at you and missed? :stuck_out_tongue_closed_eyes:

Basically a ball of metal … Don’t be sporting flip flops :footprints: whilst tweeking on the board :sob:

@claudiofiore88 and @lowGuido are both right. But IF it were me, I’d toss it and get another 4S pack. If only because you’ll need to remember to change the settings on your charger every time you charge them, and because you might not be able to assess whether any damage was done to the other cells in the pack. At the very least, make sure to charge that pack in a fire-proof bag until you’re confident that it is safe to use.

Holy shit i’m surprised there wasn’t a flame coming out of that thing. All that exposed lithium cocktail is scary.

Sorry for your loss. @treenutter is probably right though, i’d just replace the whole pack. This time you only lost one S, but with a hole that size, its possible you could lose more Ss. Ss are like the magic smoke, you cant let them out. They’re supposed to stay trapped in there.

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@ShockWave @longhairedboy this is what scares me the most… We all appreciate the supernatural powers of hot glue, but sparks+lipo=justbuyanewpack to me :smile:



If a lipo goes south replace it NOW. I’ve had one go south they don’t taper out they literary explode and if your not there you will lose everything fast. I can give more info when I get to a keyboard.

Sorry that i pump back the old thread. need some help before hook up my setup…

i having 2x 4s1p of lipo in series for my setup, recently one of the cell dead and i had remove become 3s1p and 4s1p of 5000mah 20c. can i connect them as series use on my setup?
for the VESC setting, do i need to change anything beside cut off voltage?

Don’t be weak get a grip, use two hands!

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