My Prius doesn't get driven that much anymore (sometimes left dormant for a few days at a time) and much of the time, when I do drive it, many of the trips are short (usually <3 miles, one way). So, I've been thinking of a solar charger for the 12 volt (now an Optima Yellow Top). Float chargers or battery tenders powered by AC are out of the question for me. I live in an apartment and the car is parked outside. I can't leave it unlocked w/wiring snaking into it nor leave my car powered on for hours at a time to charge up the 12 volt. Obviously, since the cigarette lighter plugs aren't hot when power is off, those won't work. I don't care to rewire them so that they are. I dropped by my Fry's and saw FRYS.com | Sunforce and FRYS.com | Solar. From some earlier threads, it sounds like I need at least a 5 watt panel. If I were to get one of these, I plan on hooking it up to the 12 volt terminals in the trunk area. No, I don't plan to disconnect the 12 volt from the rest of the car. That's too much of a pain. Some folks have mentioned the VW panels w/OBD2 port. I did find a few on Ebay and might try a local VW dealer. Only thing is, I use a ScanGauge so I'd have to disconnect it to use the VW panel. That's no big deal but I'm wondering if anyone has specs on the typical # of disconnect and reconnect cycles OBD2 connectors are rated for on cars. I don't want to wear out or damage the connector on my Prius. Thoughts? Don't bother?