How Bad is a Modified Sine Wave Battery Backup?

[Jeremy1998]

So, I've come across an awesome deal locally on a 1500va/900watt UPS. My only concern is that it's a modified sine wave inverted style, the CyberPower CP1500AVRLCD to be exact. This leads to two questions:

1. How bad is a modified sine wave for a computer power supply? 

2. I would think the UPS should just pass through the wall power when available, so the only time it should be outputting a modified sine wave would be during a brown or blackout, right?

 

I live in an area where we haven't had the power go out in like 7 years, so I'd imagine the chances of the UPS actually being used are pretty low. Still, it seems like a good idea to have my home server on a battery backup. So would I be doing more harm or good with these modified sine wave UPS's? 

[W-L]

Just now, Jeremy1998 said:

So, I've come across an awesome deal locally on a 1500va/900watt UPS. My only concern is that it's a modified sine wave inverted style, the CyberPower CP1500AVRLCD to be exact. This leads to two questions:

1. How bad is a modified sine wave for a computer power supply? 

2. I would think the UPS should just pass through the wall power when available, so the only time it should be outputting a modified sine wave would be during a brown or blackout, right?

 

I live in an area where we haven't had the power go out in like 7 years, so I'd imagine the chances of the UPS actually being used are pretty low. Still, it seems like a good idea to have my home server on a battery backup. So would I be doing more harm or good with these modified sine wave UPS's? 

It really depends there have been some cases where some PSU's will reject the power from battery backup thinking it's poor quality power. In most situations I see most times the PSU emit excessive electrical noise or buzzing for the unit trying to correct for the imperfect sinewave. Ideally the least I recommend is usually a stepped modified sinewave which seems to be more compatible. 

[Enderman]

1) not great, but some PSUs will not work at all with it

 

2) yes, and the problem comes when the power goes out instead of keeping the PC running it will switch to modified sine and the computer turns off, making the UPS useless.

 

3) just buy a pure sine wave UPS like this one https://www.amazon.com/CyberPower-CP1500PFCLCD-Sinewave-Compatible-Mini-Tower/dp/B00429N19W

[Jeremy1998]

5 minutes ago, W-L said:

It really depends there have been some cases where some PSU's will reject the power from battery backup thinking it's poor quality power. In most situations I see most times the PSU emit excessive electrical noise or buzzing for the unit trying to correct for the imperfect sinewave. Ideally the least I recommend is usually a stepped modified sinewave which seems to be more compatible. 

They call it a "simulated sine wave" in the specs, and the graphic is somewhat stepped. How would I know for sure exactly how stepped the sine wave is?

https://www.cyberpowersystems.com/product/ups/cp1500avrlcd/

4 minutes ago, Enderman said:

1) not great, but some PSUs will not work at all with it

 

2) yes, and the problem comes when the power goes out instead of keeping the PC running it will switch to modified sine and the computer turns off, making the UPS useless.

 

3) just buy a pure sine wave UPS like this one https://www.amazon.com/CyberPower-CP1500PFCLCD-Sinewave-Compatible-Mini-Tower/dp/B00429N19W

I would love to buy that one, but I am far too broke for that one at the moment. The one I found is $20. But that one you linked is literally the one on my wish list. 

[Enderman]

1 minute ago, Jeremy1998 said:

They call it a "simulated sine wave" in the specs, and the graphic is somewhat stepped. How would I know for sure exactly how stepped the sine wave is?

https://www.cyberpowersystems.com/product/ups/cp1500avrlcd/

I would love to buy that one, but I am far too broke for that one at the moment. The one I found is $20. But that one you linked is literally the one on my wish list. 

Don't buy a $20 UPS...

Just save up your money.

You said that power outages are rare so as long as your computer PSU is decent I wouldn't worry.

[W-L]

13 minutes ago, Jeremy1998 said:

They call it a "simulated sine wave" in the specs, and the graphic is somewhat stepped. How would I know for sure exactly how stepped the sine wave is?

https://www.cyberpowersystems.com/product/ups/cp1500avrlcd/

I would love to buy that one, but I am far too broke for that one at the moment. The one I found is $20. But that one you linked is literally the one on my wish list. 

Simulated usually not as precise as a stepped sinewave which is usually better. For $20 the battery is most likely gone and needs a replacement, depending on the unit they can get a bit pricey.