If you want one of these solar panels, you can get a couple of different kinds from
www.realgoods.com.  For example, they have a 100ma one to keep your battery trickle charged for
$35, and a larger unit for $70.  They also have a great selection of other solar and general
eco stuff.  They will sell you a system to power your whole house if you want, as well as
composting toilets, hemp clothes, some camping stuff, etc. etc..  They have a great catalog,
and if you are travelling north of San Francisco, they are well worth stopping and visiting.
At there store they produce all their own energy and process all their own waste.  Their
grounds are beautiful, and they even have plugs in the parking lot so you can charge up your
electric vehicle while you shop.  I have no connection with them except as a customer, but I do
recommend them.

Bill