Hey all - I've got several old SmartPower UPSes I got from a friend, probably because he thought they were useless.  I replaced the battery in one and after charging it powered up fine, but on the back it says:

"The output of this device is not sinusoidal.  It has a total harmonic distortion of 63 percent and a maximum single harmonic distortion of 52 percent."

I'd like to use it to give a few minutes' extra runtime to an old PC I'm turning into a DVR for security cams - will this be copasetic or not?  Happy to post pics if they would be helpful.

Thanks all!

I don't see why not, as long as the output voltage is correct.

These discarded UPS' are a gold mine for ham radio operators.  Just because the case got dusty does not mean the battery went bad

Maybe someone else can chime in with their opinion...

Our county emergency coordinator gave us a bunch of them from when they upgraded the sheriff's office (they are on a 3 year rotation). We then took some old UPS and tore them apart in order to build power inverters for a solar setup. Most of it is sitting right next to 6 (vertical) sections of Rohn 25 at the moment.

For a few UPS with high harmonic distortion, don't worry about it.   They are fine for consumer electronics and DVRs, etc.  

If you need longer runtime, add batteries in parallel vs adding more UPS.   The harmonic distortion is feedback the UPS spits back to the supply side once the batteries are charged.  

If you start popping circuit breakers or get a fire in your electric panel, then you have too much noise on the line.

The batteries DO go bad after a while... Although in many commercial/industrial settings, they change them out well before they fail as a precautionary measure, and often have several years of life left in them still if they are not abused. Sometimes you don't get so lucky and need to buy new batteries(a lot of complaints going around lately about SLA's coming out of China not even lasting out the warranty period).