ups question

[mikeyny]

I have acquired an older ups, apc model 350.

The guy said it did not charge the battery any more. I simple pushed in the re-set button and it works, but, it only charges to 80 volts ac. This can't be right. I have not yet checked the dc voltage of the battery yet. I want to use it to run a circulator

on the overheat zone of my wood boiler in case of a power failure. I don't think 80 volts ac would last too long. Any thoughts?? I may just pull out the battery and add it to the collection of stuff I have to put together a small windmill this summer.

                                            Mike

[ghurd]

It is probably how the meter is reading the voltage.  MSW can do that.

Check the battery first.

I would put a regular light bulb in a lamp.  See if it is just as bright on the UPS as when on the grid power.

UPS are pretty reliable.  It could be the battery is mostly bad, so the UPS can't or won't charge it enough.

G-

[mikeyny]

 Thanks for the input. I plugged in a 60 watt bulb, unplugged the ups and the bulb stayed the same. It stayed lit for about 9 minutes. I will look up the usage of my circulator  to see of it will work long enough to keep things from heating up too much. One annoying thing about it is that it puts out a series of loud beeps to let you know the power is out. I may have to tone that down a bit somehow.

                                           Mike

[TomW]

mikey;

Just FYI, some UPS units are "inverting" all the time. Even when on "grid". They run the inverter and just charge the battery at the same time.

I would suggest you test it on the UPS compared to plugged into a wall to be sure.

Just a gotcha I ran into one time a long time ago.

Good luck with it.

TomW

[dinges]

Try taping a small piece of stickytape over the hole of the piezo buzzer. That brings the noise down to a more decent level. No soldering or other electronic surgery involved.

Peter.

[mikeyny]

  The voltage is still 80 or so volts ac plugged in or not. The battery does measure 13 volts plugged in or not. I am still not sure why I only get 80 v ac. My meter seems to be ok, but I know sometimes you can get erroneous readings in certain situations. Thanks for the info. Either way it seems to work ok for now. I will probably end up using the battery for the small wind project I am hoping to build in the spring.

                                       Mike

[ghurd]

I believe we both meant to compare how bright the lamp is when pluged into the wall, compared to when plugged into the UPS.

If the output is Really 80V, the lamp will be a lot less bright on UPS power than grid power.

I expect the UPS output is fine.

G-

[Flux]

Most MSW inverters are square wave at 50% duty cycle, it works out that the rms and peak values correspond with a sine wave so they run incandescent lamps as for sine wave and the peak is the same as a sine wave for things that rectify and smooth to dc.

Assuming 110 ac will have a peak of about 154v then the 50% figure would give an average of 77v.

Most cheap meters read mean but are scaled to show the value as rms of  a sine wave.

Allowing for the form factor you should read somewhere just over 80v so that seems reasonable.

As others have said the simplest way is to compare light with a filament lamp against known 110rms.

Flux

[domwild]

Hi,

Some contributors have found the UPS has a button to disable the buzzer AFTER they had cut the cable to the beeper!

Regards,