On Sat, 31 Jan 2004 01:15:38 GMT, "Steven D.Miell"
Power is expressed in watts, which equals volts times amps in most
circumstances. (Doesn't work exactly that way in motors.) If you
double the voltage, you cut the amps in half. A 30 watt lamp would
take five amps on six volts, or 2.5 amps on twelve volts. If you cut
the amps in half, you can reduce the wire size. It also reduces the
effects of any resistances in the line, such as in the wire or at
terminals. It reduces the generator current output required to deal
with the electrical devices on the car.
Finally, and not trivially at all, it cuts the starting current for
the vehicle approximately in half, so instead of a 300-400 amp
starting load at worse, you have a 150-200 amp starting load. The
cable from the battery to the starter can be smaller, the wires in the
starter are smaller, the switch to operate the starter is smaller, and
the effects of the resistances is smaller--so they usually start
better. While you can expect a well-maintained 6V vehicle will
usually start when cold, if you had a few thousand 6V and a few
thousand 12V, you'd probably find more of the 12V vehicles starting
dependably in cold weather.
I have been thinking about changing to 12 volts on my old 1947 GMC pickup.
Here are some reasons not to do it:
The starter must be reconnected for 12 volts or it will die sooner; some of
the guages must be adapated to 12 volts; a six-volt radio will need a
voltage converter. all of the inside and outside lights have to be changed
to 12 volts; a 12 volt battery is needed; a 12 volt generator and regulator
or an alternator is neeeded
Some of the problems with six volt systems aren't hard to fix. The main
ones involve making really good ground connections, especially between the
starter and battery. The headlight ground connections usually need
improvements, too. A hot ignition system will help starting in cold
I recall converting my 52 3/4T about 20 or so years ago. Installed a 327 at
the time and an alternator. Starter came with the motor, but used a
step-down to take care of the gauges. Also changed over the bulbs, but that
was the extent of it. The advantages far outweigh the disadvantage when
converting over from a Generator. There are whole vehicle wiring kits that
can also help you in your conversion and with some minor tweeking, will make
the whole process easier.
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