Re: [A/S] UPS - was 'Electrical Problems'

["Dean Sale" <deansale@xxxxxxxxxxxxxxxxxxxxx>]

I have found used UPS's at thrift stores.  The ones I purchased had
mechanical switches that will turn them on and off.  I removed the dead
batteries and installed connections for the 12VDC from the trailer supply.
I just connected the 12V to the wires previously connected to the internal
battery.  There are two with output of 250 W 110 VAC and one with an output
of 650 W.  These units supply the electricity to run the Satellite systems,
modems, computer and television.  UPS's only use the 12V in proportion to
the output called for by the device attached.  If the TV uses 70 watts the
UPS will only draw enough 12V electricity to make up the necessary current
to run that piece of equipment (plus a small amount of overhead).  I have
found the secret is to make sure anything not being used is turned off when
not in use.  During the day the UPS's draw down is just about immediately
replaced by output from the solar panels.

There is no need to use an inverter to make 110 VAC and then plug in a UPS
to guarantee the current is acceptable to the computer equipment.

The UPS's used in this fashion still beep when the 12V gets to a low state
just like they did when the electricity went off and I was operating through
the UPS as a reserve.

I have also installed an older Trace U2512 that makes 110VAC for about six
outlets in the Airstream.  I had planned to replace the UPS's with the
output from the U2512 but I believe the quality of the AC output is better
from these UPS devices.  Looks better on the oscilloscope.

Dean