PaulAtreides
New Member
- Joined
- Mar 8, 2021
- Messages
- 37
Good morning everyone......I'm having some issues with my battery/BMS and was hoping to get some feedback from you to help me troubleshoot. My battery is a 280Ah DIY made from Eve cells (I think I assembled it the last week of March) and the BMS is the Overkill 4S 120A. I immediately did a top balance by putting the cells in parallel at a constant 3.65V. After a week of charging, the cells were STILL drawing amps, but only about .5A. At that point, I decided they were probably done balancing, so I removed the bench charger and let them sit in parallel for a day.
After that, I put them in series and connected the BMS. The first attached pic shows the battery after that first assembly. Everything looks good, right? So I thinking cool, I've got a battery. I put it in my travel trailer about a week later after doing some re-wiring to relocate the battery from the tongue and everything's good.
Yesterday morning, after some use, I check the BMS and everything's still good (battery dropped to 99%). Then, towards the end of the day, it says my battery is down to 54% but there's no way it could have dropped this low from a few LED lights and a stereo. I then connect the trailer to shore power (my house) and can see that the battery is charging, but it's only drawing about 10amps. I let it go and slowly over the course of an hour or so, it drops down to .5 amps. Doesn't make sense, right? I look through the BMS app and see Capacity Reset and decided to press it. The SOC instantly jumps to 73% (up from about 55%). The battery charges a little longer, but stays at 73%, so I hit Capacity Reset again and it jumps to about 93% (see second attached pic). FYI, I used the generic LiFePO4 profile in the BMS settings.
Now, it shows 93% and has stopped charging. I'm totally scratching my head here. Any ideas where I should start looking to troubleshoot?
After that, I put them in series and connected the BMS. The first attached pic shows the battery after that first assembly. Everything looks good, right? So I thinking cool, I've got a battery. I put it in my travel trailer about a week later after doing some re-wiring to relocate the battery from the tongue and everything's good.
Yesterday morning, after some use, I check the BMS and everything's still good (battery dropped to 99%). Then, towards the end of the day, it says my battery is down to 54% but there's no way it could have dropped this low from a few LED lights and a stereo. I then connect the trailer to shore power (my house) and can see that the battery is charging, but it's only drawing about 10amps. I let it go and slowly over the course of an hour or so, it drops down to .5 amps. Doesn't make sense, right? I look through the BMS app and see Capacity Reset and decided to press it. The SOC instantly jumps to 73% (up from about 55%). The battery charges a little longer, but stays at 73%, so I hit Capacity Reset again and it jumps to about 93% (see second attached pic). FYI, I used the generic LiFePO4 profile in the BMS settings.
Now, it shows 93% and has stopped charging. I'm totally scratching my head here. Any ideas where I should start looking to troubleshoot?