I am planning to buy a 600VA UPS as power backup for my rpi 2. Can someone please help me to find out how much time it can run my rpi?

I am running rpi with a 5.3V 2A usb charge and connected a 500 GB usb HDD.

Following UPS specifications:

Output Power Wattage    360 W
Efficiency  90 %
Transfer Time   4 ms
Output Voltage  230 V
Number of Outlet Plugs  3
Output Waveform     Modified Sine Wave
Output Frequency    50 to 60 Hz +/- 3 Hz 
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    Hello and welcome. Insufficient information, you need not only the power (VA = W) but also the energy that's stored in the battery (the "capacity") (Wh). – Ghanima Feb 9 '16 at 11:18
  • Updated my question. – rpi Feb 9 '16 at 11:30
  • @rpi the key piece of data is still missing. – Chris H Feb 9 '16 at 13:38
  • Even if the missing data were supplied it would be relatively useless without more information on the hard drive and expected usage patterns. Is the hard drive powered by the Pi, for example, or is it externally supplied? If powered by the Pi is it attached to one or two USB ports? Is the system in a constant state of churn, or is it idling 90% of the time? I think you'll struggle to get a good answer without first finding out the baseline power usage of your Pi. If it's all USB powered something like [this]adafruit.com/products/1852 would do to get some rough values. – goobering Feb 9 '16 at 13:55
  • The UPS manufacturer will have charts showing the run-time vs. load for each model of 600VA UPS which they make. – Andrew Morton Feb 9 '16 at 16:45

According to a few tissue calculations I conclude that,

  • At the usual battery capacity of a 600VA UPS (12V, 7AH to 8AH (7.5AH average))
  • completely ignoring inverter inefficiency
  • consuming 1.8A all the time

It would last about 10 hours.

You should expect about 5-7 hours under continuous full load, and about 14-16 hours when the pi isn't busy. Don't be surprised if it shuts down before that.

| improve this answer | |
  • Probably the best guess w/o any further input from the OP. – Ghanima Feb 10 '16 at 7:38

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