[FWDLK] Charging System Woes

The old style "generator" system was noted for producing less than battery voltage at idle speeds. This caused the lights to dim commonly on cars with this type of charging system. In order to make a "generator" system produce higher voltages at idle speed, a smaller pulley could be used, to speed up the spinning armature, but then the unit could explode at higher speeds. One of the reasons that the automotive industry went to the "alternator" type generator was to obtain increased output at lower speeds, and allowed better output at all speeds.

So actually, both units do the same thing. One uses a mechanical commutator to rectify the AC produced to DC, the other uses a diode bridge. They produce DC voltage limited by a regulator, and as much amperage as possible, within the voltage limits and need. The generator type needs to limit the current, as well, with a part in the "voltage regulator".

The bulbs designed for 6 volt systems have less resistance, and therefore will burn much brighter when connected to 12 volts. Their life is shortened exponentially, though. The same with motors. If you use 6 volt motors with a 12 volt base, the motors will spin much faster, but the excess current will cause the motor to burn out sooner unless extra cooling time is allowed. This is great for things like Power Windows, which are operated for only a short period of time, or a starter, if you don't crank it too long (the engine spins like crazy, though!)

Not such a good idea for wiper motors or heater blowers, because the are used constantly. There you can use a ballast resistor, or a resistor wire available at many Auto Parts store. Ask one of the older guys behind the counter.

You also have to be careful if using 12 volts with the old six volt headlights. Many headlight switches use a "make-and-break" circuit breaker in the headlight switch. If the curent flow increases enough to cause the breaker to overheat, the headlights will go out, only to come on after a short cooling period. Sometimes this is as little as a few seconds, sometimes several minutes. Take your chances, or change to 12 volt Halogens or Xenons.

Sorry for rambling, just my 2¢ worth.