Overcharging
I consider 15 to be "top of the limit" maybe push it to 15.5 sometimes. If you read the book, the electronic VR is temp compensated, and you must check it with engine warmed and battery "up" and normalized. The outline I posted above pretty much cover the possibilities. Sometimes a battery is a little "off" try swapping in a known good battery temporarily. The VR can be off but this is fairly rare. If you can't find anything else, replace that
But the key are the voltage drop checks...both ground and hot side
"How this works." The VR power (IGN) connection is also the "sensing," and this operates as a feedback loop, if the voltage the VR sees is low, it ramps it up until it's to the VR setpoint. Example. Let's say in the tests I outlined in the previous post, you have 2V drop measured. See below................
(By the way you can ALSO check the VR setpoint. With the car warm, running, and battery normalized, and if the voltage drop test gave up nothing, measure voltage from the blue "run" wire at thet ballast to the battery NEG post. If the VR is correct, it will read 13.8---14.4. And those figures are right out of the book, this chart out of the '72 Plymouth service manual)
Now, if you have 2V drop measured in the drop test, with the car running, you might well read 14.2 at the "ignition run" terminal with the engine running. So WHY does it produce 14.2+2 = 16.2 at the battery? SIMPLE. With the load on the alternator/ battery and the car running, the battery starts to sag, and there is 2V drop through the harness, so the VR ramps it up until the VR is seeing the 14.2 AT THE REGULATOR. But in order to do that, it must overcome the 2V harness drop (in this example) and so to get the VR IGN terminal up to the 14.2, it must ramp up voltage until that is so.........and the battery is boiling...............
I consider 15 to be "top of the limit" maybe push it to 15.5 sometimes. If you read the book, the electronic VR is temp compensated, and you must check it with engine warmed and battery "up" and normalized. The outline I posted above pretty much cover the possibilities. Sometimes a battery is a little "off" try swapping in a known good battery temporarily. The VR can be off but this is fairly rare. If you can't find anything else, replace that
But the key are the voltage drop checks...both ground and hot side
"How this works." The VR power (IGN) connection is also the "sensing," and this operates as a feedback loop, if the voltage the VR sees is low, it ramps it up until it's to the VR setpoint. Example. Let's say in the tests I outlined in the previous post, you have 2V drop measured. See below................
(By the way you can ALSO check the VR setpoint. With the car warm, running, and battery normalized, and if the voltage drop test gave up nothing, measure voltage from the blue "run" wire at thet ballast to the battery NEG post. If the VR is correct, it will read 13.8---14.4. And those figures are right out of the book, this chart out of the '72 Plymouth service manual)
Now, if you have 2V drop measured in the drop test, with the car running, you might well read 14.2 at the "ignition run" terminal with the engine running. So WHY does it produce 14.2+2 = 16.2 at the battery? SIMPLE. With the load on the alternator/ battery and the car running, the battery starts to sag, and there is 2V drop through the harness, so the VR ramps it up until the VR is seeing the 14.2 AT THE REGULATOR. But in order to do that, it must overcome the 2V harness drop (in this example) and so to get the VR IGN terminal up to the 14.2, it must ramp up voltage until that is so.........and the battery is boiling...............
