Posted by JimmieD on Tuesday, December 14, 2004 at 0:59AM :
In Reply to: Re: Charging Questions??? posted by Dylan on Monday, December 13, 2004 at 12:45PM :
Alternators are 120 volt a/c output, and the diode pack rectifies that to 12 volt d/c. A VOM or multimiter is not the same as an amp meter.
An amp meter measures amperage [volts times ohms equals amps]so in a roundabout way it can tell you the voltage. Amp meters in any Chrysler vehicle or any other are not a good idea at all. The amperage or entire current of the charging system must pass through it, so there is a very great potential for a disastrous short and fire, even destroying the whole vehicle in many cases! A voltage gauge is far safer and the wiring used to plumb it in is much safer overall.
The normal charging output from an alternator should be around 13.5 to 14.6 volts, and a charged battery alone, without the engine running, should show between 12.5 and 13.5 volts, depending on the state of charge and how recently it was charged.
The battery cannot discharge through the alternator because the power is transferred through slip rings in alternator that have no contact to ground when ignition is off.
The idiot light is often wired through a set of normally closed contact points in mechanical regulator. When charge occurs the points are then opened, interrupting the circuit that the light is in. The light can tell you that charging is occurring, and by its brightness some can indicate level of charge or discharge, depending on how it is wired.
The best setup is a voltage gauge wired into your ignition 'run' circuit to continuously monitor state of charge and battery voltage, but preferably only in switch-on 'run' condition, otherwise it will run down the battery over time if vehicle is not running to recharge for voltage gauge losses.
I agree with the advice: Rewire it, so you know it is right. I can post a fistful of links to modify the wiring into a bulletproof high-output system ready for anything if you like?
JimmieD