goatman Posted July 3, 2022 Share Posted July 3, 2022 its pretty hard to repair these packs without damaging more cells. see if ewheels will sell you one of their litech packs Quote Link to comment Share on other sites More sharing options...
Tawpie Posted July 3, 2022 Share Posted July 3, 2022 1 hour ago, Zutto said: I double checked and it's the left pack that has issues. My euc is at 100v with just the right pack connected. I tried using the connectors from the right battery pack and it still won't charge to full. I also did a visual inspection and the only strange thing I could find is the attached image. idk if that's just rust or maybe corrosion. ugh. I wouldn't like to find that in my battery. Does it smell at all? It looks like the plastic battery cell holder (white) is a little melted and the black is generally not a good sign. I'd for sure be referring it to somebody that knows how to deal with these things and wouldn't keep it inside my home. Bummer. 1 Quote Link to comment Share on other sites More sharing options...
alcatraz Posted July 3, 2022 Share Posted July 3, 2022 Don't use that pack until someone has investigated it. Are the cells corroded at all or just the nickel strips? Is that smudge between groups conducting electricity? Clean that up with alcohol and a swab. The welds must not be weak. If you see loose welds report it. Measure individual groups please. Not pairs. 8.4v could be 4.2+4.2 but it could also be 5+3.4v = inconclusive. Measure the entire pack too. If one nickel strip weld has disconnected one cell it means one group is running with a single cell. 1 Quote Link to comment Share on other sites More sharing options...
Chriull Posted July 4, 2022 Share Posted July 4, 2022 17 hours ago, Zutto said: I also did a visual inspection and the only strange thing I could find is the attached image. idk if that's just rust or maybe corrosion. This could be electrolyte from a li ion cell. Or corrosion from condensation. The goo seems to have reached to cells / welding spots I couldn't see molten plastic as @Tawpie - if there is some that would be a very bad sign, too. Best to get a new pack - if you don't have someone trustworthy, professionally repairing li ion batteries. As most of the cells should be in perfect condition this could be sold for diy projects... Could be one of the cases why ewheels recalled the 900Wh begode battery packs. 9 hours ago, alcatraz said: Don't use that pack until someone has investigated it. +1! 9 hours ago, alcatraz said: Measure individual groups please. Not pairs. 8.4v could be 4.2+4.2 but it could also be 5+3.4v = inconclusive. Measure the entire pack too. If one nickel strip weld has disconnected one cell it means one group is running with a single cell. He did measure on the bms pcb solder joints the individual cell voltages as ~4.19V. 1 Quote Link to comment Share on other sites More sharing options...
alcatraz Posted July 4, 2022 Share Posted July 4, 2022 Ahh ok, thanks @Chriull 4.19v is 100% and a good sign. The question is how this pack stopped charging prematurely earlier. Balancing certainly appears to work, despite the corrosion. My (uneducated) guess is there's a bad connection somewhere, heating up the pack causing moisture to enter it. Maybe look at the heatshrink for hot spots? Quote Link to comment Share on other sites More sharing options...
goatman Posted July 4, 2022 Share Posted July 4, 2022 looks like the pack sits vertical with the electrolyte running down from the first series group. that would make it possible to repair that pack, since it is the outside corner cell that is leaking. you would still need to get that whole side unsoldered from the bms but its do-able Quote Link to comment Share on other sites More sharing options...
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