Replacing Amp Guage

super99 · Dec 9, 2021

Sometime long before I got it, someone added oil pressure and amp guage to my Oliver 550. The panel that holds them is about rusted out and I am replacing them with new guages and panel. The old guage is marked plus and minus, the new guage is marked bat and load. Which wires go where??? Thanks

Dieseltech · Dec 9, 2021

The HOT wire goes to the bat terminal by itself. The other terminal gets both load AND charge wires so the needle will move as needed to pull from or charge the battery.

super99 · Dec 9, 2021

There are only 2 wires on the old one, one on plus and one on minus. Would the plus go on the bat terminal??

gregww · Dec 9, 2021

Remove it all together and put in a volt meter.

Dieseltech · Dec 9, 2021

Then put them on, and with the battery hooked back up turn on the lights. Needle SHOULD show discharge, if not just reverse the wires.

John T · Dec 9, 2021

The BAT means just what it says IE to the hot ungrounded battery post eventually, often where the big hot battery cables attaches to the hot INPUT on a starter solenoid or switch. Load is to all the loads such as lights and ignition etc PLUS the generators output which is where the BAT terminal on a Voltage Regulator (or an alternators output) is wired..

John T

Janicholson · Dec 9, 2021

The Bat and Load are likely correct if you have Negative ground. If it is positive ground treat them as opposites. Jim

John B. · Dec 10, 2021

There would need to be shunt put in if a volt meter was installed in the place of an Amp Meter. Amp meters are put in a series circuit, volt
meter gets installed to parallel circuit. Just an old rule of thumb.

Jim.ME · Dec 10, 2021

True however, I would not install a voltmeter directly in place of an ammeter. Remove the ammeter and tie all the wires from the ammeter together some where like the solenoid stud. A voltmeter, only needs a power source and ground. It can be powered from a switched terminal of the ignition switch, no shunt needed. Being on a switched terminal eliminates any battery drain which would occur if installed in parallel using a shunt where the voltmeter would be powered all the time. If overload protection is desired, one can replace the ammeter with a mounted circuit breaker (40 + amp) with stud terminals, in the circuit. Battery power on one stud, everything else on the second stud, just as the wires should have been on the two ammeter terminals.

BarnyardEngineering · Dec 10, 2021

Voltmeter or ammeter, each tells you half the story.

With a voltmeter you have to assume the charge rate by the voltage reading.

With an ammeter you have to assume the voltage by the charge rate.

When you have a voltmeter you know something is wrong when the voltage reads below 13V or above 15V.

When you have an ammeter you know something is wrong when the ammeter shows a high charge rate all the time or reads a discharge while the tractor is running.

Either way you know something is wrong.

Replacing Amp Guage

super99

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Dieseltech

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super99

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gregww

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Dieseltech

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John T

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Janicholson

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John B.

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Jim.ME

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BarnyardEngineering

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