I'm currently building a DIY battery using 4 EVE LF304 cells configured as 4S (around 12V and 300Ah). However, I plan to upgrade to an 8S system (approximately 24V and 300Ah) later on. Right now, I'm considering the 200A JK BMS available on AliExpress, which should suffice for my current setup. But I'm also pondering if it would be wiser to invest in the 300A model now for future use. Is 200A enough unless I'm running really heavy loads? And, is it practical to use two separate 4S packs, each with its own BMS, or is it better to opt for a single larger BMS? Thanks for any insights!
3 Answers
I suggest going with multiple batteries each having their own BMS instead of paralleling cells under one big BMS. I have two packs, each with a 200A BMS and they work fine for me. Using this setup, I can handle loads up to 18kw if needed without fantastic strain on the system.
If you're starting with a 4S and moving to an 8S, remember that while the voltage changes, the current won't necessarily increase—you just get more efficiency out of it. Ideally, look for a BMS that supports both configurations, like the one from JK. Given that the LF304 can discharge up to 152A, the 200A BMS will do the trick for both setups, but a larger BMS could give you more headroom if you want to be extra cautious.
The best choice really hinges on your inverter since that's what pulls the current from your BMS. For instance, in a 4S setup, if you're running a 3000W inverter, that might pull up to 250A. But for an 8S system, the draw would be much lower, maxing around 125A at 3000W. So while the 200A BMS might work in 4S, it's likely fine for 8S too. You might want to think about jumping straight to that 8S setup due to the extra costs associated with wiring for two systems.