Running for 4hrs calculation

[koki4]

I found this backup power supply that feeds 12 volt to devises (Router ,Fibre, Switch) From the mains when power is on and keeps the battery (7ah ) charged and ones power is down the battery feeds the devices.. No interruption, Very convenient and with 2 devices hooked lasts more than 4 hours load sheading..
I bought it second hand so I am not sure who makes or import them. and why are they not available at ley say Security shops??
Most of the devises use 12V supply, even CCTV, DVRs..

 

[Gravedigger]

I found this backup power supply that feeds 12 volt to devises (Router ,Fibre, Switch) From the mains when power is on and keeps the battery (7ah ) charged and ones power is down the battery feeds the devices.. No interruption, Very convenient and with 2 devices hooked lasts more than 4 hours load sheading..
I bought it second hand so I am not sure who makes or import them. and why are they not available at ley say Security shops??
Most of the devises use 12V supply, even CCTV, DVRs..

They are available in some security shops, I know that the magna-lok devices use this type of PSU or similar. I know a place in my hometown that sells these PSU's.

 

[alanB]

Here's a calculator to help you how-many-batteries-for-load-shedding