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Old 06-23-2014, 05:35 PM   #1
smurph
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Default Need help diagnosing generator / ammeter issue

I'm puzzled (as usual)!

12 Volt battery with voltage regulator.
Battery is draining down over time. Needed to recharge Sunday.

At startup and idle with battery fully charged, ammeter will not show charging as engine is revved up, but will show discharge with head or brake lights on.

With battery discharged, ammeter will intermittently but inconsistently show charging when engine is revved up.

I'm trying to locate the problem. Why am I not getting a consistent reading from the ammeter ? Is the generator not working properly and only intermittently producing output? Is the voltage regulator faulty and not allowing charging? Is the ammeter properly reading discharge but not charge?

Are there some tests to confirm that the generator and voltage regulator are working properly ?

Thanks in advance for your help .

Out at sea when it comes to electricity ,
Smurph
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Old 06-23-2014, 05:51 PM   #2
Growley bear
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Default Re: Need help diagnosing generator / ammeter issue

Are you running a generator or alternator. There is a distinct difference between the two.

Chet
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Old 06-23-2014, 06:23 PM   #3
smurph
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Default Re: Need help diagnosing generator / ammeter issue

Running a generator.
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Old 06-23-2014, 07:18 PM   #4
Patrick L.
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Default Re: Need help diagnosing generator / ammeter issue

Do you have a voltage regulator or cut-out ?

With the regulator when charge is needed its supposed to do it.

With a cut-out [ original equipment] it should charge constantly at high idle speed.

What does the ammeter read with the key off ? It should be zero,if not, there is a draw.

If the battery is drawing down then you don't have enough charge rate , or, you have a current draw you shouldn't have. To check for a draw, disconnect a battery cable [ key off] and put voltmeter leads [ or test light] on the terminal and cable end. See if the light lights or it reads battery voltage. If it does then there is a draw you shouldn't have. One of the main problems is a stuck/defective brake light switch.
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Old 06-23-2014, 09:09 PM   #5
Tom Wesenberg
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Default Re: Need help diagnosing generator / ammeter issue

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As mentioned, we need to know if you have the stock cutout, or some kind of voltage regulator. There are at least 3 different voltage regulators made for the generator, although I only make them for 6 volts positive ground.

Is this car new to you?

Did you just do something to the charging circuit, or did this problem just start on it's own all of a sudden?
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