I am currently putting together a solar system for my RV, along with new batteries and a new inverter. I have already put in 3 x 100amp Battle Born lithium batteries and their battery isolator and they are working great. I am planning to put 4 x 250w solar panels on my RV, with each pair in series and each pair connected to its own 40amp solar controller. I am looking at the Epever 40a Tracer 4215BN or the Triron 4210N. The 4210N is newer, but the Tracer 4215BN looks more robust. Has anyone had specific experience with either one of these solar controllers with Battle Born batteries? The Tracer 4215BN does not automatically recognize lithium batteries, so how easy is it to program this controller to work with the Battle Borns? I have read and re-read Will's book on solar power systems, but I am definitely new to this and would appreciate any input. Thanks.