Here are the correct voltages for a 12volt (nom.) lead-acid starter battery measured with a good meter. It refs. to a calcium-calcium type.

Properly charged, new, off-load. -- 12.8volt. (after any float charge from charging has dissipated).
Moderate load, -- 12.6 to 12.7volt.
During cranking, -- not less than 9volt.
During charging by alternator, -- either 13.8volt, or 14,4volt depending on setting in microprocessor controller. This can be set in modern cars from a laptop.

Cheers, Leedsman.

 

In most vehicles, most of the time when a battery is not charging the Rectifier/regulator is malfunctioning.
Normally that is a pretty cheap part and easy to replace.
I dont know where it is located in a Voyager yet, (since I only own one for few weeks now ) but if a Voyager operates the same as all other vehicles I worked on, why not check the cheap solutions first before going into expensive repairs?

 

Does anyone know where I can get one of these regulators from?

 

You probably can order them at your local dealer?
Ebay sells them too:

Denso Alternator Rectifier Dodge Caravan Durango RAM Chrysler Voyager | eBay

Googling the issue it seems to me that the regulator/rectifier is build into the alternator? I'm learning a little bit more about this car all the time

 

My local motor factors told me today the regulator was listed as a 'Remote Regulator' which made me think it was a separate part altogether..

 

I got a nearly new one last year from a breaker on Flee-bay for £125. Good to know you are nearly fault free.
Be interesting to know about where the Regulator is, keep up the interest.

 

On modern vehicles, alternator-charge regulation is done directly by a microprocessor. It imposes pulse-width-modulation control on the alternator's slipring contacts. Chrysler was one of the first in the world to employ this method, and crow about it. It saves current (PWM) and facilitates program adjustment in the micro. I.e. makes it easy for a technician with a lap-top to choose between 13.8volt and 14.4volt charge-maintenance.

Leedsman.

 

So is the regulator built into the alternator on the Gv?

Has anyone tried replacing their alternator themselves? Is it easy enough?

Only I see it is right at the front on top of the engine so very accessible....

 

Compared to replacing the alternator on my son's Ford Cougar V6, it should be a doddle. Just need to make sure you get the belt at the right tension.

 

https://www.youtube.com/watch?v=FTGz0PKIl84

At 7:56 this chap starts talking about by-passing the Voltage Regulator (Full Field Test). This eliminates the possibility of it being the alternator at fault and sounds like it's exactly what I need to do in my instance..

Anyone know how to do this 'Full Field test' on a GV?