Sizing the BMS for my lithium batteries

[Offgridder8888]

Hi guys, I am setting up an offgrid solar system with 3x550watt solar panels (1.65 kw total) wires in parallel with 3 solar chargers. I plan to buy 2x 24v100AH Lifepo4 batteries from aliexpress. I have the option to purchase these batteries with 50A BMS, 100A BMS, 150A BMS, 200A BMS, and 250A BMS. I plan to use batteries to connect to a 3kw off grid inverter to power my freezer, electric cooker, laptop, cell phone and LED lights. What size BMS do you recommend for that? Are there any downsides/danger/risks with going larger and choosing a 250A BMS for this application? Thank you so much for any advice you can provide!

 

[Wet1]

If you wanted to use the full 3000W from that inverter, you'd need a 125A from your 24V battery. Obviously you'd want a little headroom as most BMS wont be happy running at their max limit, so I'd order a minimum of a 150A BMS, or more if you really want to play it safe.. Then again, I'm guessing you won't be maxing out that 3000W inverter either, so 150A BMS might be fine if so. Personally I'd go larger if in doubt. No real downside to going larger (other than the cost) as it will give room for expansion in the future. Make sure your wiring can handle the load.

Also make sure your batteries are fine with this amount of discharge.