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MG TD TF 1500 - Ammeter showing about 8 amps

I've seen a few instructions and videos showing how the charging system works, what an ammeter does, etc.

Is 7 to 8 amps OK at cruising speeds? If not, how do I raise the rate? I've always seen 12-14 as the norm and have never had to adjust it on other cars.

Seems like this is elementary stuff, but we're living in a world that takes care of all this for us - I haven't had to fiddle with this stuff since I was a kid. Quite frankly, I've forgotten.


The 12 to 14 you have seen on modern vehicles is VOLTS not AMPS. The ammeter will show as much as 20 amps just after starting while the generator is replacing the energy used to crank the engine. After that it will drop to nearly zero amps with small jumps to the positive side of the meter. headlights, horn or other heavy loads will cause a momentary excursion to the negative until the voltage regulator responds with additional output. The "T" series generators were rated about 19 amps so some halogen lamps and driving lights can stress these old generators.

You can think of the ammeter as an indication of the flow of current in the system. The positive side says current is flowing into the battery. The negative indication says current is flowing out of the battery. Modern vehicles find it sufficient to indicate alternator health by indication of the voltage rather than the current.


Jim H. 1953 TD
J. M. Haskins

This thread was discussed on 18/02/2015

MG TD TF 1500 index

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