Pellet stove battery backup - pure or modified sine wave inverter? Build my own UPS? Backup power options...

[Jeff7]

The stove has 4 motors - 2 blowers, and 2 low-rpm auger motors. Would a modified sine-wave UPS like this work, or do I need pure-sine?
For the price of the pure sine, I'd almost wonder about building my own backup power supply. But I don't know what all would be involved with that - I imagine I'd need a good charging circuit, a solid-state relay to switch between mains and backup (would this present a danger of overvolting though?), and a sine-wave inverter, which I can buy at one of the various surplus stores I know of.
Suggestions? Comments? General OT nef replies?

 

[308nato]

Why not just get a GOOD generator ? Have heat, hot food, television, neffing etc.

Mine is hard wired and converted to run on LP from the main tank. Seems a better return on your investment.

 

[Jeff7]

Originally posted by: 308nato
Why not just get a GOOD generator ? Have heat, hot food, television, neffing etc.

Mine is hard wired and converted to run on LP from the main tank. Seems a better return on your investment.

How much gas do those things use? I see estimates around a gallon an hour. An extended outage at that usage would wind up costing us what the stove saves us in energy costs anyway.
That said, we have considered a small generator JUST to run the pellet stove, nothing else. The problem with that is, the generator I did see has a 1 quart tank. = refills every hour. Not an option. If we did get a generator, it would need to be a) low-output, just for the stove, b) decent sized gas-tank, and c) low-gas usage. The ready-bought UPS would be as a "buffer" to provide time to get a generator going. Otherwise, I'd need to build my own UPS, with a high-capacity lead-acid battery.

Oh, and when I say "extended outage" I mean an outage like last Christmas - 4 days with no electricity. We used a regular wood stove to keep the house both full of heat, and full of smoke - chimney seems to have a nasty, and unsolvable down-draft problem. (No suggestions for this are needed. We already spent well over $600 through the years on various methods that were "sure" to cure the downdraft.)
I do recall reading somewhere that a 200Amp battery should provide backup power for a week. If this is true, that'd be great.

 

[308nato]

We have 3 generators around the farm. The 6200 watt Porter Cable has an 8 gallon tank. It goes 12>15 hrs on a tank depending on the load. The other 2 are converted to LP and I have no idea what they use daily. Not much. A couple of solid days running doesn't put a dent in 2 1500 gallon tanks.