So I picked up an ammeter made for a 1973 celica to run in sequence with the battery and the alternator, but I wonder if the ammeter I bought is even working?

the gauge reads from top to bottom: 50, 0, -50

In instructions i found for other ammeters, it states to see if it's working by running the headlights and the fan to see if there's an amperage draw. I did such and found that the ammeter only dips by a hair, on the scale of 0 to -50, I would say it's only -1 or -2 (amps).

I started the car and the action of kicking the starter in makes the needle jump a little. up and down in a jerking motion +5 to -5 until the car starts. then it's a steady +5 (amps) at idle. If i hit the power windows, it goes up by a hair, +6 or +7 amps. If I turn on the headlights and the fan (whilst idling at +5 amps), i can barely see how high the gauge goes up, but it does go up, like half a hair, maybe to +6 amps then goes back down to +5 amps. On the scale of 0-50, 5 amps looks very very small, the needle looks like it's very close to zero.

when I drive, the ammeter goes up by a hair, like to +6 or +7, but often goes back down to +5.

I have not yet run something electrical for more than 2 or 3 minutes with the engine off to see if the needle dips more, but i may.

so query: are these the normal workings of an ammeter?

R

Well this is for a 4AG alternator, but it should be pretty close:

Idle to 2000rpm with no load= under 10A
Voltage should be 13.5-14.3volts (higher readings replace voltage regulator, lower readings repair alternator)

2000rpm and above with load= over 30A
A loaded system is when you have the high beams and blower motor on high while testing.
Lower than 30A reading, repair alternator. Note: A fully charged battery may result in lower than 30A readings.

I am facing an electrical injury with ammeter. What would be the reasons?
clamp dc ammeter

adam7 wrote:I am facing an electrical injury with ammeter. What would be the reasons?
clamp dc ammeter

electrical injury eh? Sounds pretty serious.

Where exactly is it wired in? Positive or negative side of the battery?

one wire is on the positive post of the battery, the other wire is on the alternator post. I followed the path that was shown on the very hard to read 1973 celica wiring diagrams i found online. confirmed with a better-to-read fj40 schematic. also used an autometer ammeter instruction i found online as reference.

R

To get better accuracy from the clamp dc ammeter, do I have to set the panel meter to read zero when the rectifier is disconnected?
clamp dc ammeter

Turtle wrote:one wire is on the positive post of the battery, the other wire is on the alternator post. I followed the path that was shown on the very hard to read 1973 celica wiring diagrams i found online. confirmed with a better-to-read fj40 schematic. also used an autometer ammeter instruction i found online as reference.

R

Sounds like it may be bad. Ornit cant read short bursts accurately.

Andrew

Can we repair broken ammeter at home? What are the steps for this?
clamp dc ammeter