I need Help: Revive my busted bottle battery pack

[pcliteuser]

is there a way to revive this pack of mine? it's a 52v 11ah bottle pack from luna, there's a burn part inside and i can't send it back to for repair coz no one here in Qatar wants to ship defective battery, so it's just sitting there on my storage collecting dust

Here what it looks like inside:


the wiring inside is ok no burn or whatsoever its just the inbetween the metal thingy got burned, and because of that battery won't charge at all. last time i checked it was at 51v but that was 2 months ago.



same shot but this photo was taken right after i removed it from the aluminum cover and rip open the yellow tape.


does anyone here knows how to build this kind of battery pack? what do you think caused the burn inside?
what i'm also thinking is to break it apart and maybe put it inside new battery pack "shark pack" perhaps? eventhough the bms is rounded not square shape.

[JPLabs]

Can you show what burned, specifically? Get voltages for the intact series groups and any cells no longer connected?

I think a burn was probably due to a short or a bad connection. If a bad connection burned due to resistive heating, and didn't cook a cell or damage anything else, I guess maybe it could be an easy fix. For example if a crack developed in the 'burned metal thingy' you describe, causing it to iverheat. Not very likely, IMO.

On the other hand, if it was damaged due to a short someplace: Since the BMS protects the pack leads, either that failed to do it's job (external short), or something else inside the pack, besides just what you can see burned, is also damaged. So it's probably not an easy fix.

Need to see the damage.

[HarryS]

You got me thinking about how a bottle battery is wired up. How many modules are there? I see three. Are there four? And how many cells do you think are in a module? Maybe 14?

Yeah, you need to show a pic of the burned part. Is it the dark area between the first two modules, Rather than a short circuit, It could be a break in the connection between the modules, and the sparking caused a burn mark. But then you wouldn't see any 51 volts of voltage. So whatever voltage it shows now is good to know too.

[pcliteuser]

here is some shots inside. i haven't fully break the whole thing apart.

here is the shot front facing where the on/off switch is located. on this side the wiring & solder points are clean no issues at all



and this is the backside of the battery. here you will that the is also clean no burn marks or what soever but there is 1 solder point there that has burn marks on it.





here is the close up shot







here is the voltage readout - i noticed that even the switch is ON or OFF i can still get voltage readout "not sure if it suppose to do that" :)



just like where i left off from my initial post couple of months ago, the battery is totally useless, it doesn't even charge it self and i can't even send it out to luna or someone for repair coz no one here in qatar wants to ship busted battery pack. i need help :(

[JPLabs]

I can't quite tell what I'm looking at; but I've never had one of those apart.

You still have pack voltage, so there must still be some connection through the damaged joint. If it won't charge, I'm not sure why. BMS? I think charge ports are direct, not through BMS, usually, though. So that doesn't really fit. Maybe the damaged connection has such high resistance it won't pass enough current to charge.

I guess the best case is probably that you had a defective or damaged solder joint which partly melted. If you repair that, maybe you'd be OK. I would probably want to replace the cells it was connected to, since it looks like they got pretty hot. But if they seem to measure OK (all in balance even after some use) then maybe the cells are all OK.

Check voltage of all cells. Make sure there aren't any low ones. If you can't access every one, at least check the parallel groups. If all equal voltage, there may be hope for an easy repair.

Repair the solder joint first and see if the condition improves? Live pack so be careful. If it charges after that, use it a bit and recheck cells for balance, to make sure none of them have sagged too much. You could have one dead cell in a parallel group, and still show balance until you use it for a while. So it's important to check after some use.