I'm looking to get a UPS to power a 7.5watt pump to keep my tank going for night-long power outtages. I'm looking at a 255w/350VA UPS. If i'm doing my math correctly, and being optimistic, I should be able to get enough power to last through the night. Is this correct?
Uninterrupted Power Supply
- Thread starter chanathon
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By my calculations, a 350VA UPS could power a 7.5w pump for about 40 hours.
Now, typically you won't get a full 350VA out of the UPS, but it looks like you have plenty of wiggle room.
Now, typically you won't get a full 350VA out of the UPS, but it looks like you have plenty of wiggle room.
Disregard my other post, I was looking at the wrong numbers.
Its really hard to tell with these smaller UPSs, because they don't discharge at a constant rate. The batteries behave differently for small loads and large loads.
Based off the specs, I think you'd only be able to get 2 or 3 hours of runtime from the UPS. It states that it will power 127 watts for 8 minutes, so if you extrapolate that, its ~2.5 hours for 7.5 watts.
I think for ~8 hours of runtime, you'll have to get one of the more expensive "tower" looking UPSs. The small surge protector ones probably literally all have the same size battery in them, and are only designed to run for 5-10 minutes.
The larger and heavier physically the UPS is, the longer it will generally last, because it physically has a larger battery inside of it.
Its really hard to tell with these smaller UPSs, because they don't discharge at a constant rate. The batteries behave differently for small loads and large loads.
Based off the specs, I think you'd only be able to get 2 or 3 hours of runtime from the UPS. It states that it will power 127 watts for 8 minutes, so if you extrapolate that, its ~2.5 hours for 7.5 watts.
I think for ~8 hours of runtime, you'll have to get one of the more expensive "tower" looking UPSs. The small surge protector ones probably literally all have the same size battery in them, and are only designed to run for 5-10 minutes.
The larger and heavier physically the UPS is, the longer it will generally last, because it physically has a larger battery inside of it.
Besides fluctuating discharge rates, they also suffer from degradation over time and use. The UPS itself also has some power consumption.
I use a APC 1500 to power a 56 watt pump that I'm hoping will get me 5-6 hrs. Or long enough for someone to realize the powers out.
The good part about the larger units is you can tether additional batteries and replace old ones for a lot less then the smaller units cost.
I use a APC 1500 to power a 56 watt pump that I'm hoping will get me 5-6 hrs. Or long enough for someone to realize the powers out.
The good part about the larger units is you can tether additional batteries and replace old ones for a lot less then the smaller units cost.