... if you buy from us you deal with not just a seller; the whole technical team is behind you and ... want 36V, so you can charge 24V battery, just loose the cable from the solar panel and connect ... in series, if you not sure what to do, just mail us.7. What is the Warranty Period, ... once we received your order information, we will make a contract via Alibaba(include price, quantity, manufactory necessary ...