Re: UPS as backup power

[Bill Wichers <billw at waveform_net>]

The APC Back-UPS uses a "modified sine wave", which is more of a modified 
square wave like this:
    _       _
__| |_   _| |_   _ [etc]
       |_|     |_|

Not quite as bad as a square wave, but not good enough for shaded-pole 
motors either. Air pumps run super with it though.

The APC Smart-UPS units are true-sine units though and should run any 
aquarium accessory you have. They show up on Ebay a lot for cheap, but 
usually with bad batteries. Digikey (http://www.digikey.com) carries exact 
replacement batteries from the Panasonic line for APC UPSes if you want to 
replace them. I've repaired 20+ APC Smart-UPS units like this.

The usual rule of thumb is cheap UPS = non-sine, expensive UPS = true sine.

         -Bill

>So it actually worked for you?  I didn't have the same luck a few months
>back when I tried the same thing with a few of my UPSes.  I have a large
>1250VA APC Back-UPS unit that I was going to hook up to my small
>nano-reef tank.  Unfortunately, none of my water pumps nor the CF light
>ballast would accept the power supplied by the UPS when it was on
>battery.  The lights would flicker and the ballast would crackle, and
>the pumps would clatter and make unhappy noises.  I'm assuming this is
>because of the pseudo-squarewave output of this particular UPS not being
>compatible with things like flourescent ballasts and magnetic pumps.
>
>Perhaps the UPS you used has a more sinewave-like output?  I seriously
>like the idea of having backup power on my aquarium equipment
>(especially the reef!), but none of my UPSes would work.  They are all
>easily large enough to handle the load, but they are all APC Back-UPS
>units which probably all have the same squarewave output.
>-joe
>

*****************************
Waveform Technology
UNIX Systems Administrator