I bought this to charge and maintain my travel trailer, which is on solar panels. This device is ONLY for ac current. You MUST keep it plugged into an ac outlet for it to work. It DOES NOT WORK and IS NOT compatible with solar panels or wind generators..Seller, refuses to authorize a return ... I have been forced to file an A-Z claim in an attempt to return it and get my money back.This should have been a simple oops, wrong type, return.