"Charles Vincent" wrote in message
...
oilsardine wrote:
got an Masters degree in Electrical Engineering myself...

Then I would have to assume that either eEnglish is a second or third
language for you or you have deliberately chosen to be a pendant. You are
right in that if the original poster intends to hook two 12V batteries in
series, but draw the same wattage over the same distance, the conductor
would require half the ampacity that would have been mandated by a single
12v battery, since in order to provide the same wattage the load would
have to draw half the current at double the voltage. The original poster
never constrained the problem to the same wattage -- and in homebuilt
aircraft, I doubt that constraint ever arises since the devices that one
connects to the electrical system have specific voltage requirements.
Even if his system is exclusively resistive loads, they are not likely to
behave in purely linear fashion.

Charles

Indeed, if the loads are purely resistive, and if the temperature is kept
constant to assist in keeping the performance linear, then twice the voltage
would mean twice the current and four times the power.

Peter