Amp gauge where am I going wrong??

old · Jul 16, 2011

So ok I wire up amp gauges this way but some work some do not so where am I going wrong. Alternator big post to solenoid battery post. Then a wire from there to the amp gauge then a wire from the other side of the amp gauge to ignition bit do not seem to get them to read right. So what am I doing wrong???????
Thanks

Anonymous-0 · Jul 17, 2011

My Fordson conversion chart shows solenoid [battery side]through ammeter to + on alternator. Then "ind" side through telltale to ignition switch.

Seems to work.

JDseller · Jul 17, 2011

OLD think about an AMP meter as a pressure and direction gauge. The positive and negative are the direct of the current flow. The Amps is a measure of the pressure or rate of the current flow.

So on a simple AMP meter it needs to have all of the current pass through it so it can measure the direction and rate. Generator or Alternator, the battery wire has to go through the AMP meter. The way you have been wiring them is just sending the ignition current through them. So if you just have the unit running, with nothing turned on, the AMP meter would only see the little current the ignition switch/system uses. The wire you have going directly to the battery(solenoid terminal) is carrying all of the major load. That kind of short circuits the APM meter. It jumps the current around it.

AN induction AMP meter works about the same but it just reads the magnetic field around the wire to work. The Ford tractor ones that you just run the wire through the loop or JD 200 series lawn tractors that you clip the wire through the plastic holder on the back of the gauge, work this way. They still need all of the current to flow through them.

MarkB_MI · Jul 17, 2011

I'm assuming you're talking about a tractor that's been converted to use an alternator in place of a generator. The problem is there's no longer an appropriate place to wire in the ammeter.

If you simply put the ammeter in the alternator output wire, you'll show a charge if the alternator is working. It won't actually show if you have a NET charge, but on a tractor there's usually not enough accessory load to matter. It will show more charge when you turn on the lights rather than less, for example.

A voltmeter is easier to wire up and, in my opinion, more informative.

John T · Jul 17, 2011

Rich, for an ammeter to correctly measure + charging current INTO the battery and - discharging current OUT OF the battery, THE ALTERNATOR NEEDS TO BE WIRED ON THE LOAD (NOT to battery) side of the ammeter .........

SUPPLY side of ammeter to hot battery voltage
i.e. say where big battery cable wires to
input (NOT starter) side of starter
switch/solenoid...

LOAD side of ammeter WIRES TO ALTERNATORS
big main output stud PLUS feeds hot battery
voltage to loads like Ignition and Lights etc

I know you well enough to understand this, you just had a senior moment lol

Take care Rich

John T

old · Jul 17, 2011

Well I sort of see what your saying but answer me this one. I went and looked at a tractor I have that the gauge seems to work like it should and the load/battery is hooked to one side of the gauge and the alternator charge lead goes to the other side. But ya I think I understand what your saying and the alternator hooks to the gauge not the battery directly.

Janicholson · Jul 17, 2011

I am adding a simple idea. Every thing must go through the amp gauge except the starting motor's high amps. Thus every thing hooks to the load side of the amp gauge except one #10 wire going from the Bat side of the amp gauge to the Bat terminal on the Starter switch, or Starter Relay, or Solenoid. Jim

John T · Jul 17, 2011

You got it Rich,

YES THAT TRACTOR (you looked at) HAS IT CORRECT AS I EXPLAINED IN MY OTHER POST AND REPEATED BELOW

The alternator IS ON THE OTHER SIDE OF THE AMMETER then where the battery is.

SUPPLY SIDE (Battery, often where big battery cable wires to starter switch/solenoid input)

LOAD SIDE Output of Alternator
Loads like lights or ignition etc

Keep cool down there Rich

John T

old · Jul 17, 2011

Keep coll wish we where. Been in the upper 90s for the past 2 weeks and looks like it is going to be in the 100s next week sure could use a cool down and raid but oh well such is life. Seems like we are having are Aug weather in July so hope we get Sept. weather in Aug

Amp gauge where am I going wrong??

old

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Anonymous-0

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JDseller

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MarkB_MI

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John T

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old

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Janicholson

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John T

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old

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