# 8N 12V not charging



## Greginnd (Jun 25, 2012)

1952 Ford 8N I purchased in May. The battery is not charging. It starts right up with a jump and runs great after that.

This was converted to 12 volts some time ago.

I do need to try a new battery as my trickle charger no longer seems to charge it.

BUT, there is a light that was added to it when it was converted that I guess should be lit when running to indicate the alternator is charging. I have never seen it lit.

So, if it's not the battery I need some help in tracking down where the problem is. I really don't know much about it so all the help I can get would be great.

How do I check to see if the alternator is working properly? After that, what should I check?

Thanks!!!


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## Fredneck (May 25, 2012)

with the tractor running, you should read 15 volts, or slightly higher, at the battery terminal of the alternator.

many auto parts stores will also test alternators for free, but this of course requires you to remove it and take it to them.

without knowing for a fact that the indicator lamp actually works, i wouldn't put too much faith in its status.


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## Greginnd (Jun 25, 2012)

I checked the alternator and it is putting out a steady 11 volts.


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## pogobill (Jan 31, 2012)

Is it a single wire alternator with a built in regulator?


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## Greginnd (Jun 25, 2012)

I am beginning to learn about alternators! 

It appears to be a three-wire alternator. I see the sensing wire is directly jumped to the alternator battery terminal. I guess that is not ideal? It should be wired all the way to the battery?

By the way, I was concerned that my cheapo battery charger was also not charging the battery. I checked the output of that and it only reads 9.25 volts when not attached to anything. I didn't check it when attached to the battery - maybe that makes a difference.


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## Fredneck (May 25, 2012)

at 11 volts, it sounds like your alternator is toast. i suspect all you're seeing there is the voltage from the battery itself.

not sure about your charger output. i'd try it while connected, u should see more than 9 volts and change. i have an old cheap charger myself, but i know it works fine. i'll try testing it later and see what kind of readings i get.

also not sure about that sensor wire, i'll defer that one to someone with a clue or 2


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## Greginnd (Jun 25, 2012)

The battery with the engine off shows at least 12 volts. I checked the alternator at the alternator. Tomorrow evening when I'm out there I'll check everything right at the battery terminals when off and on.


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## Greginnd (Jun 25, 2012)

If it helps at all, here is a link to the PDF file instructions for the 12 volt conversion that was done on my tractor. The previous owner had a copy of these stuck inside the operators manual.

http://www.camplulu.com/tractor/Manuals/12VoltConversion.pdf

Apparently the side marker lamp is added to prevent backflow of electricity to the excite circuit of the alternator. I guess it should be lit when the key is turned on and then it should go off when the engine runs.

My instructions only had the first part of this PDF. I need to check but I think I may still have a 6 volt coil.


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## Greginnd (Jun 25, 2012)

Ok. I did a little more testing at the battery terminals. 

Everything off it shows 12.2 volts. 
Turn the key on it drops down to about 11 volts. 
Connect my jumper battery it shows 12.7 volts. 
Start the tractor and remove the jumper battery it shows 10.7 volts. 

Interestingly the tractor seems to run better with the jumper on. So there's definitely not enough power being provided by the alternator. 

So, maybe the built in voltage regulator is bad? Or the alternator is not kicking into charge mode properly? I guess I'm wondering if this means I should just replace the alternator. 

Anything else to check?

As an aside I attached the battery charger and it shows 12.5 volts on 2amp and 13 volts at 20 amp. So I think that should be working. The gauge does indicate the battery is charged but there is not enough juice to turn the starter.


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## pogobill (Jan 31, 2012)

I read somewhere that you may need to get the RPM's up to get the alternator to start charging. Rev it up and maybe even put the lights on and see if that will excite the alternator and start charging.


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## Greginnd (Jun 25, 2012)

I had the throttle all the way. It didn't help. But thanks. I'm wondering if it has something to do with the sensor in the alternator. I just don't know how to get it into charging mode.


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## Greginnd (Jun 25, 2012)

Ok, I have been reading some more. The engine rpm only works for the 1-wire alternators. 

I realize now that the idiot light is between the sensor and the ignition switch. When th ignition is turned on, power goes through the light to the sensor on the alternator. Thus, the light should light up. Power to the sensor energizes it to start charging. When you start the engine the alternator should then be charging. And power will flow back from the alternator sensor to the light. The equal power from both sides will make the light go out indicating that the alternator is charging. 

Now, I wonder if the problem is that the bulb is burned out and no power ever reaches the sensor. One more thing to check tomorrow. I'll jump the hot wire to the sensor and see if it triggers it.


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## Fredneck (May 25, 2012)

hmmm, i'm not familiar with this setup. converted my 2N to 12 volts, as far as i know, the alternator is always putting out voltage. 

when you charge the battery, are you removing the cables and attaching directly to the battery, or clipping onto the cable ends? dirty connections there can prevent the charger from delivering a proper charge to the battery.

my charger is not a trickle, it will push 15 amps. i've learned to judge a battery's state by watching the pattern of how the amperage drops over time. that doesn't do you much good, i'm afraid


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## stephenscity (Oct 26, 2011)

Pull the alt and have it checked sounds like it is bad. That battery needs 14.5 volts at full charge and it just aint there.


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## Greginnd (Jun 25, 2012)

Bingo. I checked the light. The connection was bad. I reconnected it, the light went on when I turned the key. And the alternator is pumping out 14.5 to 15.5 volts now. Apparently it was just not getting energized. 

Now the alternator is working. I just need to get the battery to kick out enough power to turn the starter. I tried charging it with my charger but it didn't work. I'll see if the tractor will charge it up. Otherwise I may need to replace that too.


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## Fredneck (May 25, 2012)

good deal. this has been a learning experience for me, energizing an alternator is news to me. now i have to figure out if that's how mine works too


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