I think a second alternator, whilst it would involve some work in fitting
it, would be a better solution than a dual voltage alternator. Any such
arrangement is going to be either unusual or one-off, but 12V and 24V
alternators are very much off-the shelf items.
DF

"chuck" wrote in message
link.net...
An interesting thought is that the difference between 12 and 24 volt
alternators may lie only in the installed regulators. Even a 12 volt
alternator produces open-circuit voltages on the order of 50-100 volts! So
maybe (and you would need to consult a specialist who rebuilds and
understands alternators to be sure) you can get by with only a 24 volt
alternator and a switch to charge the 12 and 24 volt systems. Each system
would need its own regulator, but that's nothing big, and the switch would
also switch the alternator field connection between the two systems.
Definitely don't want to turn those switches with the alternator turning
without some special protection.

Yeah, it's a kluge. But just about any 12/24 volt system is going to be a
design headache if it is to function properly.

Just something to think about.

Good luck.

Chuck



Don Dando wrote:
"Voltage Reducers" are not all that they might seem to be. Different
sizes
are required for different loads. A miss rated size could damage a 12 V
item.

If I had the issue to deal with I'd install a 12V system in addition to
the
existing 24 V system. A simple single wire 12V alternator only requires
a
ground wire to the battery -, and the single positive lead to the
battery
+. Mechanical mounting then becomes the only challenge.

If your engine's electrical system is 24V you can run the 12 V system
dead
and still get home!

Don Dando


CyberSam wrote in message
news:BE9If.20846$0H1.15283@trnddc04...

I have a requirement for both 12V DC system and a 24V DC system.
Is it possible to charge both from a single alternator? Or should I use a
Voltage Reducer to power my 12V load from my 24V batteries?

Thanks for your inputs!