[A/S]

[dean <dean@xxxxxxxxxxx>]

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.
<SNIP>

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.
****************************************
Not wanting to sound like a Know-it_All  but an UPS is an "INVERTER".
It starts when the input drops off.
I think your idea about a used UPS would be great to run the TV and 
Receivers
and Computers.   Sounds like the cost is almost nothing.
But,  It is still an inverter - Charger so don't over charge your 
batteries when on
shore power.
See you on the Road
Dean L.
*******************************************
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