I almost built one but had no time for that project. Since you mentioned EG4, I've got one of each: Lifepower and the EG4-LL. Both are 24v and run great but the Lifepower had some trouble with rapid high amperage discharge and would shut down only in one situation, when cranking up my camper's portable A/C. I swapped them putting that one in my cabin, and found the EG4-LL starts the A/C in my camper fine, so it's okay. They use a different BMS. Each has a wire I plug into an old laptop to check lots of info via the BMS, and the cells seem to stay balanced and all runs beautifully. The first one I picked up in TX, and the second one was on sale with shipping at $100. Simple and reliable solutions for me.
