It takes 10-15 seconds for the backup battery to start feeding the house after a power failure. That's long enough to dismount external disks and maybe damage them too. So I also bought a little UPS device that provides four UPS-backup outlets (and also other stuff like a coax cable surge protector). It senses a power failure in a few milliseconds, which they say won't hurt anything. I guess I should try just unplugging it from the wall to check. On 1/12/23 6:24 PM, Robert wrote: > > From: Brian <http://www.cs..edu/~b> > > Date: Thu, 12 Jan 2023 17:51:05 -0800 > > > > Yeah, I guess I do; my phone service is also my internet provider > > (Sonic). I don't think I tried it then, though. > > Yeah, I have Sonic, but was wondering if I will need a battery back-up if > I have batteries with solar panels and switch from POTS. > > > I've just now plugged my backup disk into my new UPS. > > 👍 >