On Tue, 25 Jun 2019 12:18:00 +1300, Henri Derksen wrote:

>> 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?
>
Buy a UPS which can notify the computer when anything changes (mains
turns of or on, internal battery getting low, etc). They are available
fairly reasonably these days - starting at about £70 + VAT + P&P - as I
said, and usually will also supply a monitoring server that you can
configure to do whatever you want it to do such as shutting down the
computer after a pause to let the power come back online. Shouldn't be
hard to make it start a generator that is connected to the computer
downstream of the UPS and then stop it again when the mains comes back on.


--
Martin    | martin at
Gregorie  | gregorie dot org

--- SoupGate-Win32 v1.05