I hate battery powered lanterns with a passion, they are just lame....
I have an alaknak 12x12 with vestibule and I rock an Eco fan and small backpacking style gas lantern... If the alaknak is up, the wood stove is in it which means the thermoelectric fan will have power to move air, and in something as small as an alaknak, a fan with 100 cfm or so is more than sufficient to move the hot air from the wood stove around, it's lighter than a battery powered fan, and never needs battery's.... Ever.
This what I have and couldn't be happier
http://www.sportco.com/store/pc/Brunton-Primus®-EasyLight®-Lantern-224583-7p63408.htm
http://www.gyroscope.com/d.asp?product=ECOFAN2I've had my alaknak in single digit temps before, and between my wood stove (Colorado cylinder stove), the stack robber cook oven, a shovel full of briquette, and that fan moving the air around, it gets almost too warm, but I swear by that fan, and it goes anywhere my alaknak does