Charging Issue, revisited...., not the Voltage regulator |
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Charging Issue, revisited...., not the Voltage regulator |
Aaron Cox |
Apr 16 2005, 12:03 PM
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#1
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Professional Lawn Dart Group: Retired Admin Posts: 24,541 Joined: 1-February 03 From: OC Member No.: 219 Region Association: Southern California |
guys,
im having a heck of a time trying to figure out whats the problem. Gen light came on thursday night on my drive home. i measured voltage goin to the battery as follows: car off ~13 volts car idling 14 volts 1500 rpm 15.8 volts BAD i borrowed a new voltage regulator from bill 'grimstead' and it did not rectify the problem. all fuses are fine. all connections are solid. the belt is on nice and snug with the car off, the G light is lit car idling, it is lit, but very dim.... higher the rpm the less bright the bulb becomes.... now that i have eliminated the voltage reg as a failure mode... do i have a crapped out alternator? where is the best place to buy a new alternator? help me before the WCC... i dont want to blow up my optima.... |
lapuwali |
Apr 16 2005, 02:50 PM
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#2
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Not another one! Group: Benefactors Posts: 4,526 Joined: 1-March 04 From: San Mateo, CA Member No.: 1,743 |
If the VR is working, and the wiring is good, and the battery isn't internally shorted, the voltage across the battery terminals should never be over 15v at any time. I'm completely lost as to where you're coming up with this "load testing" business. The battery IS a load, and if the car is running there's a non-zero load on the battery, as the ignition and injection systems take up 5-6amps just doing their jobs, even at idle. So, there's always a load when the engine is running. The alternator just pumps out current until the voltage regulator stops it. As bondo said, it varies the field current to do this, and the field current passes through the brushes. Less current means less output, and the VR operates in a feedback loop, measuring the current coming out to vary the field current and keep it in bounds. My guess on Aaron's problem is BOTH voltage regulators are bad, even the new one. It's been known to happen. |
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