Originally Posted by
Stubbs
I'm going to talk to a couple of the electrical engineers at work this week, and see how hard it would be to make up a simple 50W DC-DC converter, with an input range of something like 9-14V DC.
Or instead of doing all that, I'll just buy one of
these 
.....it's not adjustable down to 11.5V, but it's at least the right input and output specs. This one's small enough and rugged enought to work in a starter box too.
Heck, I'd be OK wiring this in with my gel cell, and putting a set of terminals on my box. I'd use my AC heater in the pits, and then just use the DC one on the staging wall. At 9000mAh, it's not likely to drain my gel cell in a race weekend, and I keep it hooked up to my battery tender when not racing anyway...