Re: faint glow of the battery light

Posted by HH56 On 2012/1/18 11:08:24

Some instructions are in the electrical section of SM, but IMHO there is not a whole lot you can check without having some test equipment with more capacity than the typical volt-ohmmeter. It also helps to have an understanding of how things interact because voltage and current adjustments are dependent. Change one and it affects the other so messing one up can cause a no charge condition or seriously do damage.

Again, about the only thing you can check reliably with a home voltmeter is the voltage output. It sounds as if that is OK since the red light does go out. After things are warmed up, use the voltmeter to measure across the battery posts. A fully charged battery will read right around 6.3 volts just sitting. After measuring that, start the engine and run at a fast idle so red light is out. It should read about 7.4v at the battery. Turn the headlights on and measure again at same engine speed to see if that 7.4v is still there.

After that measurement, it gets more complicated. The max current for 52's should be set at approx 35 - 40 amps (Packard max spec is 40 but some are set less) so a heavy duty ammeter is required -- most regular meters are limited to 10A so won't work. Some expertise is also needed because you have to jumper out various things while measuring to get correct readings. Since problem seems load dependent I would suspect the generator or regulator is not putting out the full current. Lights have a CB limiting them to 20 amps but run less. Unless radio, heater, lights & something else heavy is on at the same time, draw should never reach max.

It could be an adjustment but if the gen and regulator are old and untouched it could be time for a rebuild. I would suggest taking it to an electrical shop and have them check it.