Ammeter vs. Voltmeter

[frank-mooney]

I like an ammeter in a car such as in my Series 5. Tells me right away upon startup if the alternator is charging or if not charging due to a loose or broken fan belt or wire or defective alternator.On the other hand I have a voltmeter in my Tiger II.It tells me the state of battery charge but I rarely look at it.It is normally static as opposed to the ammeter which moves its needle.Why do various experts insist that the voltmeter is better? I don’t get it.Sunbeam Specialties has a 35-0-35 ammeter[same for series 5]for the Tiger II.Other Alpines apparently use other ammeters including 30-0-30. frank mooney

[stu]

I actually have BOTH in my Tiger, but I’m an EE so what do you expect?

I can watch the battery charge and see it’s state with the voltmeter. I am reading the voltage at the ignition switch. If the car is sitting idle with the switch on, I see around 12.6V. Right after I start the engine and the generator is charging heavily, I see the voltage go up. If everything is running, and the generator isn’t charging (ask me about my drive home from the Portland ME United), or at idle with the lights on, then the voltage is lower. If I just looked at the ammeter, then all I would see is current flowing in or out of the battery, and have no idea if a cell died or something.

So with the voltmeter, you can see battery condition and charging/discharging. The ammeter gives you only charging/discharging.

Stu

[frank-mooney]

Stu,I’m going to focus more closely on the operation of my voltmeter.While I regard it as static for the most part,perhaps I need to be more focused on its readings.Then again some voltmeters may be more responsive than others. Sunbeam Specialities also has voltmeters in stock but I don’t see myself going for a replacement voltmeter because I do get a reading that appears accurate.Where do you put your two meters? frank mooney

[stu]

The Ammeter is in the conventional location. The voltmeter is in the clock hole. WAIT A MINUTE, you say, the clock hole is bigger than a nromal gauge. Right. I took the center plastic piece out of a clock block off trim plate and mounted the gauge within the resulting ring. Glued it in place, then used the standard "U" bracket to mount it in the panel.

The gauge is connected between a switched terminal on the ignition switch and ground under the dash. Mine is a heater type gauge like the other instruments, so polarity doesn’t matter.

Stu

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