I am wanting to charge a 12v Leisure battery, which is powering my Raspberry pi weather station. Depending on which Pi I use, it draws a maximum of 4 Watts.
I thought the motorhome and caravan owners on here might have some recommendations. We already have a unit that is supposed to keep a battery connected to an electric fencer topped up. It's is almost useless, but I suspect is down to the power draw from the the fencer.