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otrfun's avatar
otrfun
Explorer II
Feb 15, 2021

Cold Ambient Temps = Higher Alternator Voltage?

Our '16 Ram 3500 Cummins (220a alternator) typically charges around 14.3 - 14.4v about 95% of the time. On occasion charge voltage will drop to 13.9v on a long trip when the batteries get topped-off ...
CA_Traveler's avatar
CA_Traveler
Explorer III
Feb 15, 2021
My experience with a external accurate voltmeter is that alternators/regulators are rather poor at adjusting the charging voltage due to temperature. Perhaps related to how/if temperature is detected.

Both my RV charger and solar charger with external probes attached to the battery terminal adjust the bulk/absorb charging at expected.

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