Welcome to my J.A.M. (Just Ask Mike) Session , a weekly column where I answer your basic electrical questions. If you’re a newbie who’s never plugged in a shore power cord (or ask – what’s a shore power cord?), or wonder why your daughter’s hair dryer keeps tripping the circuit breaker, this column is for you. Send your questions to Mike Sokol at mike (at) noshockzone.org with the subject line – JAM. Dear Mike, I’m trying to boondock without a generator running at night, and am constantly running out of enough battery power overnight to run my RV furnace. I’ve been thinking about getting an electric blanket to stay warm. How does that compare to running an electric space heater from battery power? Is any of this practical without adding a bunch of batteries? — Sue in Sioux City Dear Sue-Sioux ( sorry ),Let’s explore just how much power a space heater takes compared to an electric blanket in order to stay warm in an RV. And to throw in one more variable, what about using a 12-volt DC blanket vs. a 120-volt AC blanket that needs an inverter running. You can take that to the bank… Battery banks are like, well, banks. That is, you make deposits and withdrawals. So if you take out more than you put in, at some point you’re going to bounce a check (or end up with a dead battery). Let’s first consider how much currency you might have in your RV battery. […]