Thirteen Days

That's how long I was able to operate my computer and Echo Dot on solar power (starting from a fully charged power station) before plugging back into AC.

The last two days were 1) short enough, 2) overcast enough, 3) for long enough that I was getting drastically reduced output from the panel. As of this evening the station was down to about 10% (33 watt-hours of stored power left) and would likely have drawn 25-30 watt-hours overnight (I turn the computer off, but leave the Dot plugged in), with 3-4 hours of work to do in the morning before the sun would be back up and the panel generating power at all, let alone anything like peak power. So I just plugged in rather than have to do so in the morning.

This is presumably just about the worst I can expect in terms of sunlight conditions -- shortest days, cloudy weather. My guess is that from February through November, the 160-watt panel should be enough to keep those two things running without needing to tap the grid.

But of course, I'd like to power more things, and to never have to switch from solar to house AC. The latter could be accomplished with more panel alone, but the former would probably need more battery as well (the modem and router, unlike the computer, would be running 24/7).