Calling all battery builders - is my 8S4P pack beyond repair?

I managed to break my Alien Power Pack (8S4P) this morning :frowning:

I was at the last stage of an All Terrain dual motor setup, when I had incorrectly soldered an XT connector to my vesc the wrong way around, which fried the battery when i turned it on.

The battery now has 4 burn marks up the side where the cells have melted the plastic cover, and the level indictor is only reading 5%. My main worry right now is that the battery will not turn off. I just left it outside the house hoping the battery will eventually drain itself to 0%.

Does anyone know if the battery pack is fixable or it any of the parts of it salvageable? If not, does anyone know how to dispose of the battery in the UK?

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I’m sorry to say it’s most likely dead now. Take it to a tip, they have a battery thing there.

The Antispark is dead for sure, the fets are now fused open which is why it won’t “turn off”. Have you taken the shrink wrap off and measured the battery voltage into the Antispark?

You could have even destroyed the VESC’s too, could be an expensive mistake!

Thanks for the reply and advice.

Unfortunately I have a busy day out of the house today so will not be able to work on it.

Do you know if it’s safe to leave it in the shed or is it likely to burst into flames any second?

Thankfully the vesc was a cheap flipky

I would say (although hard to know until you open it up and have a look) that it will be ok. The Antispark is dead for sure, hopefully the pack hasn’t somehow shorted itself

Cool, thanks for all your help.

This might be a good excuse to upgrade to a 10S4P as I was a bit concerned that my 8S might have been a bit weak and possibly sagged for my new setup (dual 5065 200kv on evolve AT wheels).


it was so close to completion :frowning:


And such a stupid mistake.

I think the battery should be ok. If its not, hey, you have plenty cells for a beefy power bank :slight_smile:

Be happy that you didnt start a lithium fire. That would suck much much more.


Absolutely, that went through my mind straight after cursing my own stupidity.

Does anyone know or a battery repair service near Liverpool?

It could be quite easy to diagnose yourself mate. Take the shrink wrap off and look at the wiring with a multimeter.

I just opened it up to take a look:


And I haven’t got a clue what should be connected to what

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Mate i think your picture did not upload :smiley:

What bms does it have?

Not sure, possibly from SmarTec. The number on it is pcm-l16s50-985(b).

First off please move some of the foam to check for damaged cells. Next in plug the bms balance leads and check with a voltage meter each cell group to confirm which ones may or may not be damaged. If they are all at the right voltage I would try and charge in a steel can outside. If not try pulling it apart and seeing where it’s broken or contact aps and see if they will service it for you.

I’m thinking the bms should have cut off the power to not damage the battery


Thanks for all the advise. I removed the foam and found that a couple of the batteries appear to have cosmetic damage (burn marks) and the +ve connection between the BMS and the cells has disintegrated. I measured the voltage across the cells and it looks like they are ok :grin: However the BMS is a goner :pensive:

If there are burn marks on the cells this could not be good for the cells. I would ask Alien power systems about a repair, or contract @psychotiller if he would inspect it for you

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I asked APS about battery pack repairs and unfortunately it’s not a service they provide. However they can send me an identical replacement BMS. So, to any experienced battery builders out there, would you recommend that I try and replace the BMS on this pack, or is it beyond repair?

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Looks like all your series connections burned out and opened the circuit. It looks like AlienPower systems only used single layer of Nickel this might have saved you as those series acted like a fuse. You should be extremely happy and thankful that you avoided a massive fire. Some of those cells might still be okay but I would not attempt a repair on the whole pack as there are bound to be some bad cells in there.