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MG TD TF 1500 - 52 TD Charging Follow Up

I posted just the other day about reversing the polarity on my newly rebuilt generator and it not it works fine - Now shows positive on amp gauge when car is running - Only issue is now when engine revs up so do amps - quite a bit - if engine is about at 3000 RPM amps, read almost full (+) 30 amps - I am now wondering if the voltage regulator is not working correctly - Anyone have any comments on the high amp readings? - Thanks Again! - Scott
RSC Scott Cleveland

Hi Scott...
Mine on occassion seems to charge high as well...doesn't seem to be much rhyme or reason for low charge and high charge...
If I run all the lights (driving and spot and high beams) it is just a touch below '0'...when I turn them off, it jumps up for awhile, then drops to the low plus side...
Drive it for an hour or so and see if it slowly drops... Am assuming when the battery is a bit low, it charges higher?
gordon lawson - TD 27667

You are corect Gordon, If the battery is low, it will charge at a higher rate,,,

Steve Wincze

To All -- This may be what is happening. I recently put another variation on my solid-state regulator in the TD. After starting it would go up to 20 Amps then after driving a little bit (4-5 miles) it would drop back to 8-10 amps. but it never seemed to go below that.

Last Sunday I drove to Maine for a Lobster Bake and put about 150 miles on the car. I have been checking the battery voltage in the morning before starting the car or running anything that draws current. At first it was 12.54 volts, after a few days it was up to 12.64 volts, after the trip to Maine it was 12.84 volts. That means the battery was not being fully charged by the settings on the previous regulator and it takes a few charge cycles to get it back up over 12.8 volts after resting overnight. Which is indicative of a fully charged battery.

Also I would say that if the fuel pump causes the ammeter to swing wildly the regulator is not doing it's job properly.

This sort of problem shows the need for a good digital voltmeter (multimeter). I have no knowlege of the various meters offered by Radio Shack, they may have some very good ones but I have no knowlege of that. Fluke and Agilent are the top units, Wavetek is half-a-notch below and a lot cheaper.

For what it's worth my 2 cents worth.
R. K. (Bob) Jeffers


You might want to put an external charger on and top up the battery. The see what it looks like. The little lucas genny will take a while to get the job done if the battery is low.

Check your email. I sent you a copy of the Lucas test manual.

Good luck,
Evan Ford - TD 27621

I may be a bit off (well, you know), but if the car has enough juice to start, I don't think the ammeter should be reading that high for very long. From my experience, it should show a pretty good draw right away. As you rev it, though, like to only about 2500 RPM, it should jump back a bit. Still on the positive, but not way over.

Thusly, I'd check out the control box settings per the manual. It's only a slight inconvenience.


You're description reads exactly like the problem I had. If the ammeter is always over towards the +30 it probably indicates that the voltage control box is not working properly. Leaving it like this leads to current being fed back to the generator and eventually the generator will fail - mine melted the solder on the armature windings and resulted in an armature rebuild.

Buying a new Control Box is often the simplest solution - they are reasonably cheap and easily installed.


David Wardell

This thread was discussed between 07/08/2006 and 08/08/2006

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