diy solar

diy solar

How do I size bus bars for my LiFePO4 280Ah cells?

My first question is about sizing the buss wire. Is the amps I need to cover based on the BMS, or the inverter. I'm assuming BMS, as that's it's job, right?
I'll have the Sol-Ark 15K which can charge at 275A and 2 48v 304AH batteries in parallel with Seplos 200A BMSs.

The answer could be "both". If you created a system that drew a low amount of power, but for a long period of time it would be different from a system that drew a large amount of amps over a short period of time. To be conservative, you would size the bus bars for the maximum capacity of inverter and BMS.

I admittedly am on the beginning end of learning about batteries. I get the whole parallel and series thing, but how current is available and regulated with the BMS and inverter is new to me. For example, 2 batteries in parallel. I assume whatever is being pulled from them, is going to be split. So, inverter wants 200 amps, it's going to pull 100 amps from each battery ( in an ideal world where batteries are the same, cable lengths the same, etc. ). Charging would be the same. Or, does it not work that way?

Yes, that's the way it works.

But, I'm also assuming that my batteries should be built as if I only have one battery available at a time, because that could be a reality, either because I may have to take one out of the system, or one could shut down.

That's pretty much how I built my system.

I chose to use rigid bus bars between my cell terminals. My two 280Ah LiFePO4 batteries are in my RV trailer which has seen many rough backcountry roads. I have a compression frame for each battery. I've had no problem with the connections on my terminals. In my opinion, if your cells aren't moving, you don't need flexible bus bars.
 
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