I'm in the process of purchasing batteries from China and I've noticed they use 4 AWG cables connected to the main terminals, which they claim are rated for a maximum continuous output of 200A at 48V. However, based on my research, it seems that 25mm² cables aren't sufficient for this current capacity, and I think it should actually be at least 70mm². Am I right about this?
2 Answers
You're spot on! For a 100Ah battery pack, it's common to see 4 AWG since they expect normal outputs to be around 100A. In my experience making DIY packs, I use double 4 AWG to 1/0 on the output side of my BMS. Each battery can handle 200A, but when you parallel packs, the load each one experiences is reduced.
It sounds like you have a pretty solid battery setup. If you’re working with a 314Ah battery that has a 200A rated BMS, then yes, you should be able to handle that current, provided you use the right cable size. Definitely make sure the cabling can support that load for safety!