A beautiful sunny morning today and somehow the conversation on the repeater turned to powering your radio from the sun. Paul, 2E0BHA fascinated me by saying that he and a colleague had got a solar panel and charged a battery up which would power an FT817 'forever'. I mentioned that I was interested in float charging some batteries and running an inverter to obtain 240v.
Interestingly, Paul had done this too, with a small inverter and had produced enough 240v for soldering tasks in the back of the van etc.
This is interesting to me, both from the point of view of playing radio, but also in the light of recent issues with flooding and power, we're conscious of wanting some backup to keep the freezers on at home, in case of power cuts. This might be an option. A smallish solar panel with the possible addition of a wind turbine ought to keep this going pretty much 365 days a year.
Chris, G7JGE also mentioned that he'd been reading some very encouraging reports on the increased efficiency of PV cells - so that's worth keeping an eye on too.