Finally saved enough to buy a solar-panel for my VW Camper Bus. The idea is that I can camp for a few days at a time without having to start the VW. I have a second battery installed, which is disconnected from the main starting battery when the engine is off. This prevents me from running my starter battery down and being stranded.
Second battery runs stereo, cabin-lights, and a few extra plugs for laptops, charging devices, fans, etc.
The solar panel will keep the second battery topped-up when parked for a few days. Also, in the event of prolonged power-outages at home, I can use this system as emergency power.
Total Cost: (around) $200 for panel, battery, diodes, fuse-blocks and charge-controller.
Panel is very inconspicuous in the luggage-space on top
Second Battery has plenty of fuses in case of a short. Also a diode to prevent an over-charge being sent to the engine voltage-regulator. A solenoid connects this battery to the main system when engine is running.