I've got a 310AH 12V Lifepo4 battery setup, and I'm running into some issues. When I place a load under 20A, cell 1 is dropping down to 2.81V, while the other three cells are at 3.38, 3.38, and 3.34 volts. This brand new battery has even fallen to 11.8V under a 100A load, but it's supposed to handle up to 250A! Is this a sign that something is wrong with it?
3 Answers
Honestly, it could be a faulty cell. Given that you've seen such a significant drop under load, replacing that cell might be your best bet. Just make sure to charge the new one to a voltage that matches the other cells as closely as possible.
It sounds like your cells might need some top balancing. A lot of manufacturers skip that step, which can lead to issues like what you're experiencing. I learned this the hard way with my own setup before I went the DIY route. It gives you more control and can prevent these kinds of problems!
Do you have a BMS controller installed? That might help with balancing the cells. Without it, you could be facing these kinds of drops from individual cells under load.
Yes, I do have a BMS in the pack.
I agree! Manual top balancing can make a big difference. I faced similar issues before figuring it out.