Exceed the power capacity of an UPS

[iKatoz]

What happens if I exceed the power capacity of a UPS while there is still power from the wall?

[dizmo]

I imagine your PC will lose power much, much more rapidly than it would otherwise when the main line cuts out.

[xtasemusic]

1 minute ago, dizmo said:

I imagine your PC will lose power much, much more rapidly than it would otherwise when the main line cuts out.

What he said. its a big battery, but you also have to be careful as drawing higher amperage than advertised will cause damage to the battery. but its safe to say that on UPSs they generally lowball their estimation of amperage drawing since its usually small lead batteries ( same as in mopeds ) in there and they go pretty high up in terms of amperage.

[vanished]

If it is line interactive (iirc that's the kind that only 'cuts in' when it needs to and is otherwise just a pass-through) I would imagine it should be fine but I wouldn't recommend it, you never know what might be inside or how it was designed.

 

If you have the other kind that is always converting wall power to charge a battery and then drains from that to power the PC all the time, that would be worse since you'd be putting excessive load on the rectifier, inverter, and battery.

[iKatoz]

I still have to buy the UPS, I was looking at the average and maximum consumption of my equipment and I noticed that it could draw more than 600W (very unlikely, but it can) so i don't know if to buy the 540W version or the 720W version

[Enderman]

It will probably just shut down immediately, since I assume the UPS will have built in overcurrent protection which will limit the power going to your PC.

If it just drew more power from the battery then it would probably catch fire or explode.

Any good quality UPS will not let that happen.

[iKatoz]

If I buy a 720W or a 860W UPS, could it lose efficiency with a load of 50-60W?

[vanished]

1 hour ago, iKatoz said:

If I buy a 720W or a 860W UPS, could it lose efficiency with a load of 50-60W?

All but the most expensive only cut in when needed so there is no additional inefficiency

2 hours ago, iKatoz said:

I still have to buy the UPS, I was looking at the average and maximum consumption of my equipment and I noticed that it could draw more than 600W (very unlikely, but it can) so i don't know if to buy the 540W version or the 720W version

I wouldn't buy one that's right at the limit of what you will draw.  Get one a fair bit bigger for two reasons: One, you dont want to run into the overload issues you're asking about here, and two, the runtime in battery is not linear... not even close.  ie, it will run at half load much longer than twice as long as at full load.

[iKatoz]

The best solution is to buy the 720W version, although for most of the time there will be a load of 200-300W. Also the battery life does not bother me because here the power fails for just a second, it rarely happens that there's no current for more than a few minutes.