[FieldDay] Generators and UPS

Thu, 22 May 2003 13:58:25 -0400

Steve, if you don't plug in the UPS, and use a husky battery, you really have an SPS there, but a
light-duty one for, perhaps, intermittent service. Try it out, see if it will work for your load.
You might be OK. Just watch out for overheating.
If you do decide to charge the battery from the internal charger, I would monitor temperatures
closely. You may want to take off the cover & run it open, even with a small fan blowing on the
board. That should help.
Arthur

"Steve L." wrote:

> Hi guys, thanks for the responses.
>
> I have modified an older APC 400VA UPS with a dead
> battery to run from an external 12V marine battery,
> but it doesn't have any switches inside, just five
> PCB-mounted pots without labels.
>
> I guess I could mark their positions and dork with
> each one to figure out what they do. Probably one or
> two are charger related (and really, what do I have to
> lose here, the charger is disabled).
>
> We don't have laptops and one of our radios doesn't
> run from 12VDC (imagine!).
>
> 73, Steve N4SL
> --- Phil Lefever <[email protected]> wrote:
> > At 15:09 05/20/2003 -0700, you wrote:
> > >I've yet to find a commercial 'computer type' UPS
> > that
> > >will run from my generator.
> >
> > Yep it is a common problem, especially from a
> > smaller
> > generator. Likely the UPS is triggering from sagging
> > voltage from the generator when it is under load.
> > Like
> > the other post said you need to look for an input
> > voltage
> > trigger level adjustment on the UPS. All my APC's
> > have
> > a dip switch that allows selection of a lower
> > voltage
> > trigger point, usually they are set by default to
> > the
> > higher voltage. It may work once you flip the
> > switch.
> >
> > The question I have is why do you actually need a
> > UPS?
> > I assume it is to run the computer so it won't crash
> > every time the power sags for a minute (or the
> > generator
> > runs out of gas). In our case we get around this by
> > using
> > laptop computers ONLY. Even though most of our are
> > old and
> > have worn out batteries in them they will all run
> > for a
> > few minutes without power.
> >
> > The other advantage of using laptops is that they
> > usually
> > create much less RFI since they don't have cables
> > (antennas)
> > running to the keyboard and monitor to radiate
> > garbage. The
> > other thing I like about laptops is that they are
> > considerably
> > more portable ;) The only complaints I have with
> > them is that
> > some of the switching power supplies are noisy
> > (ferrites on
> > the cables help) and they don't have enough serial
> > ports to
> > network when running CT. Now that we use WriteLog at
> > least
> > the serial port issue is resolved.
> >
> > 73
> >
> > Phil
> >
> ----------------------------------------------------------------------------------------------
> > Phil Lefever, KB�NES                  Field day Chairman
> > Twin Cities Repeater Club             W�BU 3A MN
> > Burnsville, Minnesota                 http://www.tcrc.org
> >
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