I just had a brain storm.....
Couldn't you use a UPS (Battery Backup Unit) as a power source for a pelter? Say hook up the pelter directly to the internal 12V battery on say an old 250W unit.
OR just use the battery charging unit to run the pelters directly?
Those things (most of the time) are designed to trickle charge the batteries however the over all unit IS designed to handle very large 12V loads for long periods of time. (depending on the unit you purchase)
(have LOTS of small UPSs lieing around my house, want to put them to use
What to you think? Comments? Suggestions?