[_whiteCaps_]

A few things that I've needed to deal with in my off grid setup:

I like the MidNite solar controllers.

LiFePO4 batteries are great, with a few caveats:

  - you must use batteries from the same batch, ie you can't upgrade capacity piecemeal, to avoid degrading the new ones  
  - cable lengths are important because even small differences in resistive losses between batteries can mean that one battery is doing more charging / discharging  
  - you can't charge below 0\*C, which I'm assuming could be a problem in New England

[jandrese]

Not being able to charge below freezing shouldn't be a problem if you keep the batteries indoors. Is there a reason why you wouldn't? Fire concerns? Or is it just a space issue?

[_whiteCaps_]

Yes, sorry, I was in a rush and didn't explain enough. For our usage, the cabin isn't occupied during the winter, and can drop below 0*C occasionally. The solar system is turned off though, so we don't worry about it.

If you're permanently there, it shouldn't be a concern. Sounds like modern BMS can disable charging at low temperatures so maybe not a worry for you at all if you're buying new batteries.