Issue

For whatever reason it didn't seem to want to charge via solar. The two batteries were in parallel, and it was either always in a standby or in a discharged state while the other battery was charging. After two days at the Earth ship, it would be down to 0% while the other one would be hovering around 32 and, in my opinion, was handling all of the load that we were using.

I even switched things around in terms of positive and negative from the solar controller as well as to the inverter. Seemed to always turn out the same. Upgraded from a 30 amp to a 60 amp, solar controller and… Same issue.

I have three 200 W solar panels. They seem to bring in a lot of amps to the solar controller but… The lithium battery just didn't seem to like it. The lead acid, however, always charged it up. And… Yes, I made sure the solar controller was configured for lithium.

Thoughts:

Everything points to one pack’s charge path disabled by its BMS (temp/ sensor/ protection), not a controller or wiring problem. 

Settings

Notes

• Notice that the switch setting is ON. Could there be a thermal switch in play here?
• Discharge Overcurrent set to 10s at 220A. Could lower to 5s.

Teardown Process

Picture showing thermal switch and low temp sensor in newer version:

Capacity Test

Discharged at 10A. Pulled 293 Ah over 29 hours.

References