Simon eloquently wrote, among other things...
>I would leave the resistor in and
>rig a switch to short it out if you have to restart the car after a spin
>with a low battery.
A lot of the newer external starting solenoids have an extra spade terminal
designed to give full battery voltage to the coil during starting. Any
solenoid can do this - just run a bypass wire from the starter motor
terminal directly to the coil, and run the normal one with the resistor from
the battery side of the solenoid. Also, resistor or no resistor ain't a
binary choice. You could always get a resistor with a sightly lower
resistance to drop the voltage somewhat, gaining a midpoint between no
resistor and the stock resistor that's expecting an alternator to push it.
I would imagine that the DC resistance is what we're worried about here, and
I might start by selecting a value that drops say 20% of the supply voltage
by measuring the resistance of the coil and finding a 10 - 20 amp resistor
that was 25% of the value of the DC resistance of the coil. I'd bet that a
1.5 ohm resistor would be pretty right.
Brian (who can't do second order differential equations, but remembers Ohm's
Law)
Brian Evans
Director, Global Sales
UUNET, An MCI WorldCom Company
|