# Need help in buying a battery back up UPS

#### yotano211

I have an old apartment with kinda bad power connection. The power will shut off for about 1-2 seconds every 1-2 months and its causing damage to computer mining equipment.

I bought some battery back ups this week but I dont know if the output is enough for 760watts and 6.47amps at 120volts in the US. The computer equipment are mining computers that draw 760watts.

The one I bought is this model.

At the bottom it says that the output is 120volt- 3.75 amps -- 450va 260W
Is this is the maximum output it will do. I only need this UPS for 1-2 seconds so the computer equipment doesn't damage anymore from a power loss.

Can anyone recommend one stronger or is this good enough.

Last edited:

#### Bill_Bright

If you look at the specs of that UPS, it shows 260 watts is the capacity. So clearly, that one is not big enough.

Note the formula to convert VA (volt amps) to Watts is:

VA x PF = W​

When no power factor (PF) is listed, you use 60%.

The PF for that UPS is an odd 57.8% since 450 VA x 57.8% = 260.1W

That's close enough to 60%

To find VA from W the formula is:

VA = W/PF​

So, to convert 760 W to VA you use:

VA = 760/.60

VA = 1266.66​

Therefore, you need at least a 1300VA UPS. I recommend a 1500VA.

Last edited:

#### yotano211

What billbright said. I one of these and it works well enough for my needs with a 750W system:

https://www.amazon.com/dp/B009TZTGWK/?tag=tec06d-20

What is your budget per UPS?
I am trying not to go over \$100 per UPS x 12 mining machines.

I just need a UPS to protect against 1-2 second power loss. Last time it happened it caused some damage to the graphics cards.I dont need power to run the machines for 5 minutes just enough for those few seconds.

I guess the output has to be enough amps for 7-8amps. I dont know anything about UPS or battery back ups.

#### Bill_Bright

Like power supplies, you want to invest is "good" UPS with AVR (automatic voltage regulation). You can find budget UPS but they typically have output voltages that are less regulated and they often have slower cut-over or response times.

ATX Form Factor standards for power supplies require them to "hold-up" output voltages when there is a loss of input power of just 17ms or less. That is not a lot of time for the UPS to sense there is an outage, then cut-over to battery backup. And sadly even many of the top quality power supplies have a difficult time meeting that 17ms requirement.

Since you are looking at supporting 12 systems, I recommend you contact UPS makers directly and see if you can cut a deal for a volume discount.

Staff member

#### yotano211

Like power supplies, you want to invest is "good" UPS with AVR (automatic voltage regulation). You can find budget UPS but they typically have output voltages that are less regulated and they often have slower cut-over or response times.

ATX Form Factor standards for power supplies require them to "hold-up" output voltages when there is a loss of input power of just 17ms or less. That is not a lot of time for the UPS to sense there is an outage, then cut-over to battery backup. And sadly even many of the top quality power supplies have a difficult time meeting that 17ms requirement.

Since you are looking at supporting 12 systems, I recommend you contact UPS makers directly and see if you can cut a deal for a volume discount.
What is 1500VA, is that 15amps total output

#### Bill_Bright

What is 1500VA, is that 15amps total output
VA = Volt x Amps.

Don't worry about just amps. You only need to worry about VA or Watts.

#### yotano211

VA = Volt x Amps.

Don't worry about just amps. You only need to worry about VA or Watts.
ok, is the up UPS in the link good enough.

#### Norton

##### Moderator & WCG-TPU Captain
Staff member
ok, is the up UPS in the link good enough.
The ones you linked were rated for 1500VA/910watts iirc so they should be able to handle the 760watt load you quoted in the OP

#### yotano211

The ones you linked were rated for 1500VA/910watts iirc so they should be able to handle the 760watt load you quoted in the OP