: 
:    Hams can legally run up to 1500 watts.  It is very unlikely, however,
:    that a ham would be running that kind of power from a car.  Ham rigs
: 
: Not possible either.  You'd need about a 300 amp alternator for
: just the amplifier.  I can just see it.  You need to slow
: down on a downgrade,  so you hit the push to talk button.

Well - 100+ amps anyway. Transmissions are generally for a short interval.
The battery would supply the rest. Of course, if you transmitted too much,
you would run the battery down.

It really would not be that much of a brake.  Even at 50% efficiency, 1500
watts would only consume 4 horsepower.