Anybody using a solar battery charger/maintainer?

[weijing3333]

Wondering if anybody is using one of those little to charge or maintain equipment batteries?
I’ve got a hunting property with no electricity and the electric start equipment like the 4 wheeler tends to sit for long periods of time in the winter. But removing the battery is too much of a PITA.
Anyone using one of those little solar chargers? I figured I could just put one up in the south facing window of my shed and plug it into the ATV. Would it still work through the window glass or do they have to be outside?
Since I’m looking at getting a tractor as well, I figure this could be a good little technology to keep batteries fresh. If they actually work.

[alice915]

The has the solar battery charger.