Cheaper and more efficient to carry more battery to extend range now that lithium is here.
With some freebie sliding glass door panels and about $100 in materials I cut my (electric heat) heating bill by about $50 a month by adding passive solar heating to the house. Combined with another $50 a month saved by insulating the attic, a single months savings can power my ebike for years. It's a much better use of your solar dollar.
Insulate the house first, caulk gaps, etc, replace windows if you can, cover em with insulation at night if you cant.
Then do solar heat, for water or spaces.
The low hanging fruit is the one to pick first, before you buy the expensive extra tall ladder for the rest. With the savings that passive solar gives me, I can consider the bike, the computer, the tv, to all be "solar powered" in a way. I consider the power I used to use heating the house to be new, "free power".