This is my beginner pack:
View attachment 65764
Orange is the new black.
This bank is for outage backup and a bit of ballast so the solar PV can run the pool pump and a few sundry items. They are not for regular cycling. Did a test "outage" night before last and no issues at all. 7.5 hours overnight and I was down to 84% SOC.
It's definitely been a good learning experience. I'll eventually look to progress to LiFePO4 one day if/when I want to move to daily cycling for house loads. But that's a different financial equation. They need to come down in price by quite a bit (at least half).
From my perspective these pre-loved SLA units from a data centre significantly lowered the cost of entry to doing a project like this. Same for my solar PV and rails, picked up pre-loved stuff. I would never have bothered with such a project using LiFePO4 at the moment (not much in the way of pre-loved LFPs about).
Pre-loved comes with extra risks of course, especially when it comes to batteries, but this particular brand/model of paperweights seem to be very tradable items, and at worst they can go to a lead recycler.