H Electrical Problem

Doug Kieta · Nov 22, 2021

I took my H to a shop nearby to have the oil pump replaced. While it was there, the shop owner noticed I had a 12V alternator conversion, and said that with an alternator, you need to use a voltmeter rather than an ammeter, and so he put a new voltmeter in. He ran a wire from the voltmeter to the ground post on the battery. When I tried to start the tractor today, the battery...a brand new one...was dead. I charged it, and the tractor started right up. I disconnected the new wire. What should I look for to correct the obvious current drain that discharged the battery? Never had a problem with the old ammeter in place.

TractormanNC · Nov 22, 2021

Put the ammeter back in. An alternator does not care whether there is an ammeter or a voltmeter or an idiot light or none of the above in the system if it is wired correctly. Sounds like yours is not wired correctly and stays on all the time and drains the battery.

55 50 Ron · Nov 22, 2021

Either a voltmeter or ammeter is good with an alternator - no right or wrong answer to this. HOWEVER, a voltmeter needs to connect in parallel between chassis and any point that is electrically equivalent to the plus post of the battery. DO NOT connect The voltmeter in series as was the ammeter.

A small point in favor of a voltmeter when using an alternator, is that with an alternator with a current rating typically considerably more than a generator, the ammeter will typically peg to the + side when an engine first starts. That might be hard on the ammeter, but I see lots of ammeters in use with an alternator.

gene bender · Nov 23, 2021

Where is the DIODE in your charging system that prevents battery drainage

Jim.ME · Nov 23, 2021

What alternator? One wire or 3 wire? 3 wire needs a diode (or indicator light, or resistor) to prevent back feed, from the alternator, which can prevent engine shutdown in some cases. One wire doesn't need a diode, etc.

You said one wire of the voltmeter goes to ground. Where does the power for the voltmeter come from? If the power wire is not hooked to a switched source, the battery will drain through the voltmeter.

This post was edited by Jim.ME on 11/23/2021 at 03:59 am.

Doug Kieta · Nov 23, 2021

It is a 1-wire alternator. Yesterday I charged the battery. The charge seemed to hold and I was able to start it. Overnight I put a small trickle charger on it to make sure it was charged this morning. No
luck. Dead. I checked the wiring of the voltmeter. One wire is connected to one of the terminals of the push-pull ignition switch and the other to the negative terminal of the battery. What am I missing?

old · Nov 23, 2021

With the ignition turned off does the volt meter read zero volts?? If it doesn't then the meter it self could be why the battery goes down

John M · Nov 23, 2021

Sounds to me like hes got it wired on the battery side of the ignition switch.

Doug Kieta · Nov 23, 2021

One thing I did not check. Leaving for Thanksgiving, so will sort it out when I get back. Thanks for the help. Happy Thanksgiving to all and pray for our country.

Brownie450 · Nov 23, 2021

A Voltmeter is a high resistance measuring device.
It shouldn't drain your battery even if hooked up
all of the time. It should correctly be installed
so it reads when the switch is on.

I'd start by disconnecting wires to find where the
current is draining.
Jim

Rich'sToys · Nov 23, 2021

Was this a new 12 volt conversion, or had it been on there for a while? Was it working OK when you took it in there? If yes to either of these questions, then why did they mess with it? I'd say it should be up to the shop to make it right if they're the ones who screwed it up.

cuby · Nov 24, 2021

Sounds like he needed more cash in his pocket. No need to put a volt meter on it. I never have.

Janicholson · Nov 24, 2021

Some one wire alternators are known to drain more current than others. One wire alternators are actually always on but draw only a few Milliamps. some draw mush more than this, and are a drain. Jim

Doug Kieta · Dec 2, 2021

I have just gotten back to trying to resolve my problem. I suspected the problem might be in the push/pull ignition switch so I removed it and found that it does not function when checked with meter probes. I have ordered a new switch. Can you direct me to a schematic that includes the push/pull switch, a momentary push to start ignition switch, and a ballast resistor to the coil? I can't seem to find that combination, all of which are on my tractor. You can probably tell I am lost in the world of electrics.

BarnyardEngineering · Dec 3, 2021

Sounds to me like the dummy wired in the voltmeter directly so it is active all the time.

If the voltmeter read 12V even with the switch off that is the case.

Voltmeters draw power. The power supply to the voltmeter needs to be switched like any other device on the tractor, or it will drain the battery.

H Electrical Problem

Doug Kieta

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TractormanNC

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55 50 Ron

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gene bender

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Jim.ME

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Doug Kieta

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old

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John M

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Doug Kieta

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Brownie450

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Rich'sToys

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cuby

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Janicholson

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Doug Kieta

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BarnyardEngineering

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