Netonix Forums

I have a WS-12-250-AC that draws aprox 50w according to the Bar at the top of the gui.

Now this switch is running on a UPS that has a 700w AC Inverter/Charger with a 100amp/h 12v Battery.

How can I estimate the runtime of this switch when running solely on battery?

Looking for the right formula to make this estimate so any help is appreciated.

The best place to start would be putting an ammeter between the battery and inverter - this will give you a very clear idea of how many amps you're drawing.

Since we don't have that, here's an example of the power math.

50w / (approximate efficiency of inverter, say 80%) is 62.5w, which at 12 v is 5.2A. Watts = Volts * Amps.

When you're trying to figure out how many hours your battery will last, you: (rated amp hours)/(amps)=Hours, so 100/5.2= 19.23 hours, or 19 hours and 13 minutes. Battery Capacity = Amps * Hours.

That's the gist of the math, anyway.