"John Gaquin" wrote in message

If you know, or know someone who works for, a VW dealer, that could be a
good source ( i.e., $0). Every new VW comes off the transport at the
dealer with a small solar charger wired to the battery and suction-cupped
to the inside of the windshield.

Clarification: the panel is about 10" x 10", and is not actually hard-wired
to the battery. The panel cable merely plugs into the cigarette lighter,
providing enough trickle to keep the battery alive.