Hello Martin,

> Also, unless you're planning to convert the disk's enclosure to run off
> a 12v supply (3.5" disks run on 12v, 2.5" disks on 5v) and you're planning
> to use a 12v supply (i.e. an SLA rather than a Li battery with 5V USB
> output, then you are stuck with using a mains voltage UPS. Worse,
> a basic UPS won't have the ability to tell the computer that the mains
> is off and they're now on battery power - this is necessary info if you
> want your RPi to shut down cleanly if the power outage outlasts the UPS
> battery capacity.

How do you do that?

> That alert capability still seems to be missing from any UPS under
> around £70 to £100 (the Eaton 5EiUSB, from VPS www.vps-ups.co.uk
> is £67.42 including VAT. They're OK - I have a Riello
> UPS I got from them a few years ago and regularly buy 7AH SLA batteries
> from them because their prices are as good as any.)

Another solution could be to start a generator if the power outage is longer
dan say 1 hour. Or better use the Voltage low signal to start the generator.
Many inland ships do that.

Henri.

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