MTFCA Forum

Would it be possible to run a car without an ammeter?
How would you configure the wiring if possible?

Yes, you can

the generator must have it's output grounded
the battery wire would go directly to the BAT position via the barrier strip

there are so many cars wired to be functional but not according to how the factory intended that any further or more specific advice would not be prudent. There are lots of schematics floating around on the internet, not all of which are accurate. For an accurate schematic which will lead you to success, go here, and print Ron Patterson's .PDF file and follow it: https://mtfca.com/phpBB3/viewtopic.php?f=2&t=29719

Considering that a Model T came unequipped for an oil gauge, speedometer, clock, you can operate a Model T with out an ampere meter.

The two wires that attach to the factory meter are either jumped, or both wires an on one meter terminal.

So the striped yellow and the plain yellow would go on the same position on the junction block?

Yes, but you wont get the warning of the impending burn up of your generator when there is a cutout or other failure. Thats what I look @ it for primarily. Any sign of issue you need to get out & ground the output terminal immediately to save genney. In my case I have it so wired & flip a switch with idiot light to shut it off.
Ford wouldnt provide this relatively expensive thing if it wasnt necessary.
This would be foolish to delete.

Neither one of my 13's have one.

Yes. Just think of the ammeter as having a wire between its to posts. So all you need to do is remove the wire from the ammeter to the BAT position on the ignition switch and then disconnect the other wire on the ammeter and connect it to the BAT position on the ammeter. Click on the image to enlarge it

Original Smith wrote: ↑

Sun Jun 19, 2022 12:32 pm

Neither one of my 13's have one.

Original Smith couldnt have generator motors in 13's.

Model T’s didn’t have amp meters until generators were introduced in 1919. The non generator cars in that era would have the coil box ignition switch and some cars would have the dash panel ignition switch with a blank over the amp meter I think. Maybe others on the forum would know more about that paticular point.

Professor Fate wrote: ↑

Sun Jun 19, 2022 9:01 am

Would it be possible to run a car without an ammeter?
How would you configure the wiring if possible?

1. Yes
2. Simply add a jumper wire across the ammeter terminals.
3. WHY? Not a good idea! You'd have no indicator as to impeding electrical problems, like fires maybe... Wire the car as it's meant to be wired. It ain't so difficult.

To state that pre-generator cars never had them is a moot point and does not present an argument one way or the other as to whether this can, or should, be done.

Letting Model T owners know about the evolution of a Model T is an excellent educational point since some may not know that Model T’s didn’t have generators or an amp meter until 1919. The question was asked if a generator equipped car could be run without an amp meter and it was answered that it could be. Cars did come with a backing plate on the ignition switch assembly that was on the instrument panel in 22-23 Model T’s that didn’t come with a generator from the factory according to the T encyclopedia.
The car in question in this thread evidently has a generator so it would be best to have the amp meter in working condition since it came from the factory that way.

Dan's second question is easy to answer.

An ammeter has to be placed in the line from the generator to the battery to measure the amount of electrical current being sent to the battery.

To run without an ammeter, one only has to remove those two wires from the ammeter and fasten them together with a splice.

Years ago, I had a Model A that had a strange habit, at night only, when the headlights would light up like flash bulbs on a camera, and all the lights would burn out.

That was real exciting when driving at 50 mph at night with no moon!

That happened several times, before was looking at the speedometer one night when it happened and saw a flash of light in the ammeter.

What caused the problem was a loose terminal on the ammeter and all the generated current was going in the light circuit to cause the voltage to go up to around 36 volts, which was more than the lights could handle or not share with the battery.

That is why the generator is basically a wattage device capable of a 75 watt output and can provide 10 amps at 7.5 volts all day or be adjusted to provide 5 amps at 15 volts or 3 amps at 25 volts.

You must know the output is stable within those ranges though.

If you can't find a Model T ammeter, I would suggest you buy any analog ammeter and install it to the same connections that the T ammeter would be installed. You must find one with charge and discharge polarity. Any of the ammeters made for the older cars up until the days they changed to "idiot" lights would work. Then when you can find one made for a Model T of your vintage, you could install it as Henry would.
Norm

Norman Kling wrote: ↑

Mon Jun 20, 2022 6:26 pm

If you can't find a Model T ammeter, I would suggest you buy any analog ammeter and install it to the same connections that the T ammeter would be installed. You must find one with charge and discharge polarity. Any of the ammeters made for the older cars up until the days they changed to "idiot" lights would work. Then when you can find one made for a Model T of your vintage, you could install it as Henry would.
Norm

Now that you mention it. An idiot light would be at least a safety replacement.
Better than nothing.

When I was a kid at these things, someone taught me how to make an ammeter bypass that would still actually show discharge or charge in a general direction way.

I ran my '25 for 15 years that way with no issue and keeping a low approach to replacing as my early T years were done on 'nickel and dime' budgets.

John Regan rightfully took me to task over the approach I used and posted, complete with reasons why...I tried to find it for you but I'm not too good at searching past posts.

Maybe someone smarter than me can find Johns reasons why....

Complete Tractor (on line) has an inexpensive universal 0 - 30 amp meter for use on a farm tractor. it will work.
They are under $16.00
They say:
30 Amp Meter Ammeter Tractor Auto Equipment - Chrome Non Lighted
Item #: 3000-0554
Complete Tractor amp meters deliver a precise reading of amperage

Accurately measures electrical current in the system
Amp meters are also known as ammeters
An essential accessory to gauge the operational health of the electrical system
Pledge of total customer satisfaction is backed with 1-year warranty

Here is the link.

https://www.completetractor.com/new-30- ... lsrc=3p.ds

I think this is the thread that George was talking about. I found it by doing a Google search for "regan ammeter bypass mtfca".

http://www.mtfca.com/discus/messages/33 ... 1368269697

The generator output terminal provides a direct short to ground when the generator is not turning fast enough to produce a current.

A red light hooked to each side of the cutout would glow red when there was no output, but the battery side always has the 6 volts on it and that does not turn off by the ignition switch, like a modern car system, so the light would always be on when the engine was not running fast enough for the generator to charge the battery.

The generator output terminal provides a direct short to ground when the generator is not turning fast enough to produce a current

you sure about that?
would be pretty hard to build up if it was shorted to ground, don't you think?

Hi All,

Here in Belgium I use a Sparex 30Amp Ampere meter S61162. They sell it as replacement for the Fordson Dexta Amp-meter. It will need a little adjustments to fit in the pre 1926 switch plate but it works well.

For running without the Amp-meter you just need to bridge the old meter ( be sure it isn't shorted to the ground!!!) and run the engine. If you want to know if you generator is charging (not how much), just connect a test light between the generator post "NOT THE CUT OUT POST" and the frame.
As soon as the generator start to generate current, the light will light up, as the engine is stopped the light will go out.
A good working cut out will prevent the battery current to go through the light and the generator and kill the battery when the engine is stopped and the switch is OFF.

As I rebuild a generator, the first test I do is make it run with only a 12V 10W test light connected between the generator post and the generator body.

Just try to help.
Andre
Belgium

OK Scott, you could say that and be correct, but it goes through a brush, a few wires, and another brush to get to ground.

You will read just about a dead short there when the generator is not spinning.

The field coils produce a magnetic field that excites those wires, and they pass on the resulting current they collected through that same terminal when the generator is spinning.

The generator output terminal provides a direct short to ground when the generator is not turning fast enough to produce a current.

which I questioned, and that statement is quite different from what you are now saying

You will read just about a dead short there when the generator is not spinning

in any event, my point is, it is not a short, in any circumstance. It is a low resistance circuit, through windings, which is an entirely different thing than a "direct short to ground". If that definition of "short" is valid, then for example, MAG coils are "shorted" as installed.

I'm not trying to pick a fight, but for folks who are already mystified enough by generators to the point of often spending more for an alternator than fixing original equipment, this sort of unintentional misdirection or vagueness may only serve to confuse things further for them.