Solar Shed: Part 14: Backup Power

I’ve just finished three posts about how I mounted my solar panels for my solar powered office (panel mounts revision 1, panel mounts revision 2, east facing morning panels).  I’ve got 2850W of solar panels hung for an office that can run, in a pinch, on just over 200W.  But winter days are short, winter days can be dark, and winter can have inversion layers out here that lead to a month of clouds in a bad year.

This is a companion discussion topic for the original entry at

(Comments from Blogger)

2016-10-25 by Aaron

Have you worked up a schedule to properly test and run the generator just to make sure? E.g. once a month, more or less 30 days apart, you startup the generator and verify that the panel switches over correctly? You know, the kind of proper BOFH things :slight_smile:

2016-10-25 by Russell Graves

The clouds have been doing that for me this week…

But, yes, I try to run the generator for about half an hour every 2 weeks, just to make sure things are working.

2016-11-04 by Ned Funnell

Can you comment on the price of power generated by the generator, with and without depreciation of the asset?

2016-11-05 by Russell Graves

Nope. I don’t have nearly enough data to give you that. Nor do I really care. Right now, that number is badly distorted by the fuel pump leak I have to fix, and I don’t have a kWh meter on the output side of the generator (yet).

To me, the power is worth what I’m paying for it, as it allows me to work reliably out there, even with cloudy weather, and it keeps deep discharges off the battery pack.