Chris We have 5 Solar Panels feeding 4 130amp batteries and we never run out of power. If your batteries are sealed you can only expect them to last in top condition for 3 years. If you go the Plasmatronics route make sure you get a shunt big enough to handle your inverter (if you have one). Don't worry, the solar guys you take it to should know all this. Ours was changed from the Steca by a 12 volt guy in Perth, which is where we are currently waiting for the Caravan show next week. Cheers Mark