Something like this?
There are a ton of voltage reducers on the market. I think 12v to 6v is most common??
Cole Hersee has a lot of electronics stuff.
E&G Terminal in Commerce City carries a lot too. Good for local pick up http://egterminal.com/
I like the idea of having 3v available from the battery. Paging Dave......paging Dave?
I would like to be able to connect a SPOT transmitter into my vehicle for GPS check ins and to avoid using AA bateries. If that is even possible?