I have an Autosleeper Symbol, the dinky little 85amp leisure battery is situated under the driver's seat. Space is restricted so there isn't room to fit a bigger one. I already have a Powerpack 400 Plus but as it is charged from the mains I don't believe I can top it up from a solar panel. This is my plan. Get an extra leisure battery to use as a 'stand alone' unit and charge it with a solar panel. With an inverter I will be able to run low power appliances without draining the main leisure battery. I want it to be portable and do not intend to link it to the other leisure battery. I know there are some very knowledgeable folk on here so I look forward to your ideas and suggestions.