Hey Marty , the battery box in the frame is made from plywood , the ends and sides are 1/4", the top and bottom are 1/2", sealed and painted black , one side is removable with weather stripping to seal out the rain. Left over pieces from my kitchen reno I'm in the process of doing . It fits tight in the frame and the controller is also a tight fit below it. I used plastic conduit u-brackets to bolt it to the frame and it is very solid . I worry about the battery overheating as there is no ventilation , may have to modify it as the temperature warms up .