Thread: Cold Starts
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Old 12-14-2020, 11:57 AM
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Diseasel300 Diseasel300 is offline
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Quote:
Originally Posted by BillGrissom View Post
So, it isn't the current output, but rather the setpoint of the internal voltage regulator. That makes sense. My other vehicles (Chrysler) show 14.3 V with the engine running. I think that is standard for voltage regulators. 13.5 V sounds low. I'll have to check my 300D's, but vaguely recall I've seen the normal 14.3 V. You don't want >15 V since that can start dissociating the water in the battery to H2 & O2.

If yours is low, perhaps swapping in a new Vreg/brush kit will fix it. You can do that with the alternator in the car, and the part cost ~$15.
When cold, the External-fan Bosch alternators do charge around 14V. They are designed to droop when they get hot. Replacing the regulator/brush assembly will not fix the issue since they are performing as designed. Lousy design and something that designers of voltage regulation equipment have tried to get away from for over 50 years. The later Internal-Fan alternators are designed NOT to droop.
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