How to determine if solar unit is working

My sky unit went off line two days ago. It’s been going off line periodically every few days for the last week or so. I finely found the battery display button and the battery on the display is showing 2.12 V and a replace indication.

In the northwest we’ve been pretty dark lately including the darkest day on recorded a little while back. Is the solar unit not getting enough light?
I’m going out in a bit to slap in some batteries to see if it comes on line.
My unit is

Might this be a solar unit issue?

A post was merged into an existing topic: Failing solar panel accessory (SPA)