Ammeter question....

[RickB]

A

See message #16.... And it's all about reference point which in this case of float voltage of battery...

Dale

Yeah, I saw that. Nothing there disagrees with what I said. The reference point of a volt meter is zero which is the absence of voltage. Battery voltage can vary depending on condition and state of charge. Being variable even within a narrow range battery voltage is not a reference point.

 

[Fuddy1952]

It's really simple. If you disconnect the + positive battery lead (a negative ground system) and then insert an ammeter there in series, it's going to show you the current (amps) going into and coming out of the battery. It's that simple!
Except there is one problem...the starter motor! So first time you crank on it, drawing hundreds of amps of current, your ammeter will peg and fry.
So the battery + positive had two wires. One heavy gauge big fat cable going down to the starter. Another smaller lead going to everything else. THIS is where you want to splice in your ammeter. Ammeter + to battery +. This shows by meter pointing left how much current the battery is draining off such as lights, etc.
Then start it. Running the alternator or generator will be putting current back into battery, needle moving right indicates how much. At idle a generator isn't as efficient as an alternator so with lights and any other electrical thing on needle probably will move left (discharge)...rev the engine and if all's well it moves right (charge).

 

[WranglerX]

A

Yeah, I saw that. Nothing there disagrees with what I said. The reference point of a volt meter is zero which is the absence of voltage. Battery voltage can vary depending on condition and state of charge. Being variable even within a narrow range battery voltage is not a reference point.

Oh but it is absolutely battery voltage as reference because battery (at stable output-at rest) is actually zero point in relationship to if system is charging or discharging... Voltmeter only reads/displays change in system voltage not from open circuit.,..

Stick one of these on your tractor and tell me what it reads other than when ignition is "off"....

Dale

 

[RickB]

Oh but it is absolutely battery voltage as reference because battery (at stable output-at rest) is actually zero point in relationship to if system is charging or discharging... Voltmeter only reads/displays change in system voltage not from open circuit.,..

Stick one of these on your tractor and tell me what it reads other than when ignition is "off"....

Dale

When the ignition is off so is my voltmeter. When my truck ignition is off the voltmeter needle reads zero.
We aren’t going to agree on this. My view is a reference point is just that, a fixed point.
You contend a reference point is whatever value battery voltage happens to be. If that were the case charging voltage would be displayed as 1.8 or 2.0 or whatever the differential happens to be.
At the end of the day I am not convinced no matter how many times you tell me I am wrong.

 

[Richard]

We still do not know HOW you wired the amp meter in. Please inform us!

If you have put it in the charging circuit, it will never show a draw.

The Amp meter might be only showing large draws or gains, depending on its Amp range.

It is the same principle as if you hooked up a multi tester on Amp setting. (Most multi testers can not handle the tractor Amps and can/will be destroid )

My apologies.

I rewired the entire tractor (brand new harness).... IF I recall the instructions correctly, there was a wire that came back from the alternator and another wire that came up from the starter/solenoid. As I recall, it bridged these two items. What I was wondering at the time was do the wires go "A/B" or "B/A" and did I have them backwards. I put them in as per the instructions.... I just had an uncertain feeling in the back of my head.



Well... I thought I still had the harness installation instructions. If I do, I can't find them yet.

I don't know WHICH wire that may have come from (presumption from the alternator) but I'm 99% sure the other end went to the battery.

 

[Richard]

i've read some of these other comments....

Now, I don't know where the wire originated. The instructions said (essentially) "Wire W-174 goes to Ammeter (-) and wire Q-645 goes to Ammeter (+)"

So I can't really swear what went where. I CAN however, say that being a pretty detailed type person, I did what the instructions told me to do so I'm confident that wires 174 and 645 were placed where they were supposed to be placed. I'm pretty sure the "drivers side" (left side of tractor as sitting on it) terminal worked its way down to the starting solenoid. I'm not really positive on what wire went on the "passenger side" of the ammeter. I always presumed it was one of the alternator wires (and as the charge went through the ammeter.....it came out other side to go down to the solenoid which had a direct wire back to the battery)

I just presumed that after starting, the batteries would be down a bit so the meter would show negative as the batteries recovered their discharge from starting the tractor.

I'm beginning to conclude that I was simply in error on what it was telling me as again, it's never been in the negative (don't really think I've noticed with lights on and engine OFF)

 

[WranglerX]

When the ignition is off so is my voltmeter. When my truck ignition is off the voltmeter needle reads zero.
We aren’t going to agree on this. My view is a reference point is just that, a fixed point.
You contend a reference point is whatever value battery voltage happens to be. If that were the case charging voltage would be displayed as 1.8 or 2.0 or whatever the differential happens to be.
At the end of the day I am not convinced no matter how many times you tell me I am wrong.

It reads "0" because it does not have a reference voltage It's out of service.....

Dale

 

[Richard]

Let me change the subject slightly......

I have an ammeter. What if instead, it was a volt meter.

As a practical matter, what's the benefit of one over the other? (if any)

 

[ruffdog]

This backs up the statement you said in your first posting. You are measuring the output of the alternator. Thus, it is wired wrong. Read the posting that Fuddy1952 made earlier.

agree....if it is hooked up like you think, then the lights would turn on with the wire disconnected from the ammeter. I think the OP should keep the ammeter and get it wired correctly.:2cents:

 

[aczlan]

i've read some of these other comments....

Now, I don't know where the wire originated. The instructions said (essentially) "Wire W-174 goes to Ammeter (-) and wire Q-645 goes to Ammeter (+)"

So I can't really swear what went where. I CAN however, say that being a pretty detailed type person, I did what the instructions told me to do so I'm confident that wires 174 and 645 were placed where they were supposed to be placed. I'm pretty sure the "drivers side" (left side of tractor as sitting on it) terminal worked its way down to the starting solenoid. I'm not really positive on what wire went on the "passenger side" of the ammeter. I always presumed it was one of the alternator wires (and as the charge went through the ammeter.....it came out other side to go down to the solenoid which had a direct wire back to the battery)

I just presumed that after starting, the batteries would be down a bit so the meter would show negative as the batteries recovered their discharge from starting the tractor.

I'm beginning to conclude that I was simply in error on what it was telling me as again, it's never been in the negative (don't really think I've noticed with lights on and engine OFF)

It sounds like you have the alternator and the battery on the correct sides of the ammeter.
Where are the lights and other such loads connected into? Those should be on the alternator side of the ammeter and it sounds almost like they're currently on the battery side of the ammeter.
if you turn on the key and turn on the lights with the engine off, does the ammeter move it all? If my suspicion is correct, it will not move because it is connected on the battery side of the ammeter so it bypasses it.

If you were to switch the wire that provides power to the lights and other loads from the battery side of the ammeter to the alternator side of the ammeter (you could even put it on the output post on the back of the alternator if that is the most convenient place to put it), you should see the ammeter start moving when you turn the lights on with the engine off and stop moving when you turn the lights on with the engine on.

Aaron Z