Never been one to let the carrier drop

I wanted to write a little bit about what I’ve chosen to do for my solar battery bank because I think that the popular approach is less safe than what I’m doing.

Note that I am running a 12 volt system – but you could use this same approach for higher voltages. You would need to have breakers or fuses for midpack string equilization as well if you did. Feel free to ask me about this.

What I’ve done is first put a fuse on the positive terminal of every battery – this is a marine fuse, direct attaches to the battery post. Then I have 2 10 AWG wires going from each battery to ground, and 2 going to the battery breaker for that battery. Each battery has a 40 amp breaker.

The intention here is that if a battery were to get severely out of balance, it’s breaker would trip during charging because it would get a unreasonable amount of charge current. Every month or so I check to make sure I have no tripped breakers.

Beyond that, if a battery were to have a short circuit fault in it’s BMS, the fault current would be limited to what that battery could supply. I have seen many people advocating 4/0 or bus bars between batteries in 12 volt systems and I think this is potentially quite dangerous – especially in a large pack such as mine. (I have 12 280 AH batteries, for a total of 40kW of stored energy – if each battery contributed 250 amps of fault current, this would make for a eye popping 2500 amps.. I would be pulling bits of battery off the ceiling, not to mention that would be a very difficult arc to quench)

I would like to encourage DIY solar folks doing a battery bank to consider using my approach (many little wires, one breaker per battery) rather than the more popular (big bus bars between batteries) approach.

So, the US is currently involved in a war where, basically, we’re blowing up someone else because we cancelled a treaty we had made where they agreed not to develop a technology we already have. We cancelled the treaty. Then we got mad that they were developing the technology – which we already have – which we have already used – and bombed them. Then, we got mad and started a war with them. And started committing war crimes like threatening civilian topics.

I am ashamed to be a US citizen. We are thugs. We are a oil company with a army. We are on the side of wrong.