The repeaters we deploy all have battery backup and solar to keep those batteries charged. Of course our primary source of power is hardlined electrical power.
We've actually had a recent case where one of our repeaters lost power for four days. We had enough battery backup & solar to stay online for three of those four days. (We're in process of adding additional battery to extend uptime in event of a longer outage.)
After I wrote that it dawned on me that they are in the damned mountains. In New England getting a signal over a mountain isn’t that much of a struggle.
We have a repeater on “our” mountain that can hit a receiver 40 miles away on 2M. Our mountains would be small hills in Utah.
I stand corrected.