Question UPS for a Corsair RM 850w ?

Jun 13, 2024
4
0
10
I'm trying to figure out what UPS would be appropriate for my build, pcpartpicker puts my average wattage to just under 500w.
I don't need it to work for long period of times, just to get me thro 1-2 minutes blackouts so i can safely shut down my PC.

 
A 1000VA battery backup is rated at 600w for 4 min, do note that over time the battery will get weaker and you're backup time will be shorter. You should also make it a practice to replace the battery every 3 years, sooner if you have to use the backup feature often throughout the year.

Not only will you need to power your computer but also a monitor so you can see what your doing.
 
You only have a couple things to check.

First check the watt number not the VA number they are related but they advertise VA because the number appears bigger. You want one at least as large as your power supply. You really don't have to go a lot above because it is doubtful you are really using 100% of the capacity of your power supply.

Next check the run times. This is complex because they cheat and rate them at different loads. like 1/2 or 1/3 or rarely full load. What you can do is look up the replacement batteries it uses...you are going to have to replace them in 3 years or so anyway. If you find one uses a 7ah battery and the other a 9ah battery you get a basic idea how much power the UPS has to start with. 9 amp hours means it can deliver 9 amp of power at 12 volts for 1 hour. Of course one you convert it to city power of 120 or 240 volts and high amp draw rates that number goes down massively.

Last if you can afford it try to buy a true sine wave UPS. Modern computer supplies because they are so efficient need very clean power. They in theory can get damaged by power that is not sine wave. Not so sure how big a risk this really is UPS makers like to scare people. It would be more a concern if you were running 24x7 on a UPS but a few minutes a years will not cause much issue.
 
Last edited:
Jun 13, 2024
4
0
10
You only have a couple things to check.

First check the watt number not the VA number they are related but they advertise VA because the number appears bigger. You want one at least as large as your power supply. You really don't have to go a lot above because it is doubtful you are really using 100% of the capacity of your power supply.

Next check the run times. This is complex because they cheat and rate them at different loads. like 1/2 or 1/3 or rarely full load. What you can do is look up the replacement batteries it uses...you are going to have to replace them in 3 years or so anyway. If you find one uses a 7ah battery and the other a 9ah battery you get a basic idea how much power the UPS has to start with. 9 amp hours means it can deliver 9 amp of power at 12 volts for 1 hour. Of course one you convert it to city power of 120 or 240 volts and high amp draw rates that number goes down massively.

Last if you can afford it try to buy a true sine wave UPS. Modern computer supplies because they are so efficient need very clean power. They in theory can get damaged by power that is not sine wave. Not so sure how big a risk this really is UPS makers like to scare people. It would be more a concern if you were running 24x7 on a UPS but a few minutes a years will not cause much issue.
I was looking at a Tecnoware UPS ERA PLUS 900 because i figured the conversion would be 900VA to around 550 watts but in their page it says just 450 watts, there's a 1100VA alternative but we're getting to almost a hundred bucks with that and if it's overkill i'd rather just get the less powerful one as long as it still works but i'm not sure, it also doesn't say anything about true sine wave so i assume it's not that kind.

Basically i'm just trying to figure out what VA/wattage to look for, considering i wouldnt use it for more than like a minute in the occasion the power does go off
 
The problem is you also need to factor in worst case power draw. Even when you are not running on the UPS battery the UPS is only designed to pass a certain amount of power. It is more of a issue on battery but most UPS will have a overload light that comes on if you exceed the wattage.

Hard to say get something similar to a killawatt device and monitor your actual usage.
 
Jun 13, 2024
4
0
10
The problem is you also need to factor in worst case power draw. Even when you are not running on the UPS battery the UPS is only designed to pass a certain amount of power. It is more of a issue on battery but most UPS will have a overload light that comes on if you exceed the wattage.

Hard to say get something similar to a killawatt device and monitor your actual usage.
I bought one of those measuring devices u mentioned and the max i use is just below 470w, so i think i'll look around for a 550ish ups maybe with the true sine wave u were talking about the other time