SOT: Eaton 3S Mini UPS

One more potential over-thinking. Maximum input voltage is shown as

Laptops and tablets have an internal battery, so you would do well to keep them plugged in and charged in case the power goes off. Often that's possible, eg if a storm is forecast. This widget has USB ports that can be used to charge tablets (and some small laptops).

It appears they're on Amazon:

Theo

When we had a significant storm at the beginning of the year EE, O2 and 3 cell towers all went down or emergency call only within one hour, and even the emergency call only went down after 2 hours

I thought if mobiles couldn't hear anything from the base-stations, they weren't supposed to transmit anything at all, let alone transmit on max power?

It depends on how heavily loaded it is. At full load, many UPSs with built in batteries will only last a few mins - long enough to save what you were doing and do a clean shutdown.

At partial load you can get significantly longer run times. (I can probably got 40 mins out of my 1kVA UPS when it is just running one PC and a couple of LCD screens, plus assorted smaller bits of kit like switches etc)

Possibly. Although if the power cut is long enough you may lose the broadband as well as the mobile signal.

Low to mid 240s is very common. Often the supplier will set the level around that, so that at times of heavy load when the local network will sag a little, it is still at a reasonable voltage.

So it can be safely ignored. The allowed spec for mains voltage in the uk is 230V +10%/ -6% So between 216V and 253V

In reality modern electronic stuff almost always has a switched mode PSU, and they will usually run on pretty much anything from 90 to 250V without any problem.

This is why I thought a dedicted UPS for the router would be a good investment.

This is true but I think it's what the bookmakers call an each way bet.

The fritz box router supplied by Zen Internet is a maximum of 30W and typically 10W if the wi-fi, lan and dect are all in use.

It arrived. 12v output is spot on. But it doesn't have the third battery contact which is used by genuine Makita batteries to signal to turn off the load when the battery is low. Without that it'll kill the battery by over-discharging it, and once over-discharged the battery refuses to charge again. It might be fine with fake batteries that don't use this signal.

It's going back.

Theo