OK, somebody check my math here...
I completely agree that a blow torch to light is a great idea (or gel). But you still need much more battery than most people realize, according to my calculations. Here goes...
The most efficient pellet stove of which I'm aware (in terms of electricity) is the Quad Mt. Vernon AE. I've measured mine at 27 watts when only the combustion and convection blowers are running, and the auger motor of course. In reality is would be safer to assume about 30 - 35 watts, but let's go with 27 to be generous.
27 watts at 12 volts produces 2.25 DC amps (27 / 12). So, in a 24 hour period we would use 54 Amp Hours (AH), calculated as 2.25 * 24.
Now, you CAN buy batteries of several hundred - even several thousand - AH. But try finding them at a local distributor, and try moving them (pretty darn heavy). In reality, something near 110 AH at 12V is about the practical limit for most people in home use, at least for a single battery. You can vary your combo of amps and volts in terms of putting various batteries together, but you're basically dealing with the same physical limitations of space (and $). The cheapest you'll normally find that type of deep cycle battery is in one designed for marine use (at about $90), which isn't "true" deep cycle, but it's good enough for our purposes. A car battery would do in a pinch, but you might sacrifice many months of its life so it's not advised.
So with 54 AH being used per day you could theoretically get about 2 days out of a single 110AH, 12V battery. But if you want to keep that battery healthy and ready to fight another day, you don't really want to take it below 80% discharge (or 88 of our 110 AH). Many people will recommend not going below 50%, but we're not going to be cycling these batteries often, so we'll be liberal with their use. That would give us about 39 hours of use for an efficient stove that operates on DC power internally, like the MVAE. (54 * .8).
However... Most stoves aren't designed to operate on direct DC inputs like the MVAE, so we'll need to connect our battery to an inverter to get AC power, and they are just not efficient in terms of how they convert DC to AC. In fact, a 20% inverter loss is commonly recommended as the figure to use for modeling and planning. So with our 20% inverter inefficiency factored in, we're going to need to back things off a bit more. In fact, we're now looking at just over 31 hours out of our 110 AH battery. Looking at it another way, if we want to get through a full 24 hours (at which point we will need to recharge) we need an 81 AH battery, again assuming 27 watts, a 12V battery, maximum discharge of 80% and 20% inverter loss.
Having access to a golf cart would of course help, as you would have more than one battery (probably 6V batteries, actually) and they would be big honkin' things. But you would also need the skills to wire them in parallel, rather large cables to safely connect them, etc. And personally, I don't have a golf cart lying about...
). Charges my laptop when the heating system is not running. A watt meter helps a lot with this. 
