You can add batteries to ANY power supply to increase the duration of the power supply. Read this thread:
A hand fired stove requires the draft from the chimney to pull air through a FULL BED OF COAL. There is no way to significantly reduce the quantity of coal being burnt. You can turn down the air to try to slow the burn rate, but you still have a LOT of coal burning, and making a lot of heat. Get the air setting wrong, close the door and go to work, and you can come back to a burnt down house, or a frozen house. A hand fired stove is a finicky animal 'till you have mastered it's personality, and this takes at least a season of burning to learn.
With a stoker, the feed mechanism feeds a small quantity or a large quantity of coal onto the grate, there is an electric fan forcing air through the small quantity of coal. The thermostat and on some the computer controls the feed rate to maintain the heat output.
Ron, the more I think about your house and situation, I think a Propane fired, space heater is the way to go. Even with a super-nice new stoker with the latest bells and whistles you still have to buy coal, get it delivered [or buy a truck and do it yourself] store the coal, carry the coal into your living space, and carry the ashes out. Just one 'OOPS' and your carpet is history.
Coal aquistion, storage, movement, pricing, and ash disposal take up weeks of my time, if not months.. Certainly MONTHS this year.
If I had a small well insulated house, I'd never consider alternative heat sources. They take way too much time and effort and have to become a HOBBY or they become a CHORE. That is why you see stoves for sale on Ebay and in the papers. The burning of coal is pretty much a Hobby with a warm outcome. Like cutting, stacking and burning wood: a Hobby with a warm outcome. I used to burn wood too!
I can get online and order and pay for a refill of my propane tank, even if I'm on the other end of the country.