8N Overcharging battery

[MoC]

I have a 1947 8N, front mount distributor, 6 volt system with the positive ground. I recently did a complete tune up including a new voltage regulator. Prior to tuneup, the charging system kept overcharging the battery. Water and acid continually overflows. After tuneup, it still overcharges.

Somewhere in the back of my mind, I remember that you use to do something with the voltage regulator when installing a new one. For the life of me, I can not find any reference to this procedure now. It seems like at one time the new voltage regulator were sold with an instruction sheet.

I checked the voltage output off the generator and it is only 5.1 volts. When I check the manuals all it talks about is replacing the voltage regulator but this does not help.

Any help in stopping this overcharging?

 

[forddoc]

import regulator? they don't shut down and will boil a battery and fry the gen. I would go with a Borg Warner or Echlin(NAPA) both made in USA and work correctly. The procedure you are thnking of is to Polarize the regulator.

 

[Bob]

First of all, you need to check the charging voltage and verify that it is indeed over the desired 7.4 Volts.

A bad (sulfated?) battery will boil over and spit acid even at a normal charging voltage.

If the voltage IS high, you need to check out the charging system.


You are thinking of POLARIZING the GENERATOR, which is typically done by jumpering the ARM and BATT terminals at the REGULATOR.

This needs to be done if the tractor has sat unused for a LONG time, the battery polarity has been changed or the generator has been taken apart or banged around.

Since your's IS charging, not to mention OVERCHARGING, polarizing is NOT needed, nor will it help your overcharging situation.

Make sure the mounting feet of the regulator are grounded and that the "F" or "FLD" wire is NOT shorted between the reg and generator.

If all that checks out, try taking the "FLD" wire off of the terminal at the generator. The generator should NOT charge. (Proving the "FLD" terminal ISN'T shorted at the generator.)

At this point, you've narrowed it down to a bad regulator.

 

[Bob]

Or, more correctly, polarize the GENERATOR!

 

[forddoc]

well yes, but you do it at your regulator. trying not to confuse him. sorry

 

[Bob]

NO apology needed, for gosh sakes.

I just like to tell it "as it is", what's really happening when polarizing is done.

 

[Greybeard - PA]

To my best knowledge, the only thing that can make a system overcharge is the voltage regulator. Please know that not all new ones come out of the box set just right. In a perfect worid this would be true, but such is not usually the case in the world where I live . . .

Get out your voltmeter, put it across the two battery terminals and see what you read with the engine at fast idle. If it's above specs, eithe adjust that new regulator or take it back and swap it for another. Lots of 'em have rivited covers, and parts houses frown on returns after the rivets have been drilled, JMHO

Gopd Luck

 

[MoC]

I will have to check the wiring to see if there is a short. The original voltage regulator was working fine and then it started overcharging. The new one is doing the same thing.

As I said previously I checked the voltage output and it was only 5.1 volts at the generator.

 

[Cutty]

(quoted from post at 21:16:37 02/21/10) I will have to check the wiring to see if there is a short. The original voltage regulator was working fine and then it started overcharging. The new one is doing the same thing.

As I said previously I checked the voltage output and it was only 5.1 volts at the generator.

Well I'm no tractor guru but I don't see how you can be overcharging at 5.1 volts. at that rate your battery will soon die from undercharging. I think Bob may be onto it with a bad battery. How old is your battery?

 

[MoC]

The battery is less than six months old. I will be checking the wiring system tomorrow for a short. I am watching the amp meter and it shows the charging all the time. It shows a negative when I first turn on the key and then to positive charge until I turn off engine. This is the way it acted prior to the overcharging started. I keep replacing the water in the battery.

 

[Bob]

A 6 Volt battery being charged at 5.1 Volts is NOT being overcharged.

Either your voltage reading is erroneous or the battery needs to go to the "Boot Hill for batteries"!

Sounds like you have a shorted cell, though.

 

[Cutty]

What is your battery voltage with the engine off? It should be over 6 volts. If it's 5.something then you do indeed have a dead cell. Take that battery back under warranty. They can test your battery at any auto parts store. Your charging system seems to be working fine. Have that battery tested.

 

[souNdguy]

IMHO.. doing it at the regulator is harder than needed... you can simply use a jumper wire from bat hot post right over to the generator armature stud.. electrons don't care...

soundguy

 

[souNdguy]

"To my best knowledge, the only thing that can make a system overcharge is the voltage regulator."

Actually that's not very precise in this case.

Since the 8N uses an A circuit charging system, that means the field coil is looking for ground from the regulator, because of that, a chaffed wire running from the generators field terminal can touch chassie ground and cause a max charge or full field situation. Or, the insulation grommet at the field coil stud can short to the case of the generator and allow for a full field / max charge situation. in both cases, the vreg could be perfectly fine.

soundguy

 

[MoC]

Maybe I should have started this conversion with the battery is being constantly charged. I changed out the three wires today and nothing changed. Tomorrow I am going to check the ground positive wire and make sure the voltage regulator is grounded good. If that does not work, then I will be pulling out the battery and taking it down to be tested.

The parts I purchased all came from the local Ford tractor dealer.

I once again checked the voltage at the battery with the engine running. I am still below 6 volts while running.

With engine off, I registered 6 + volts.

I just read through all the responses and realize I have not pulled the Field terminal wire at the generator. I will do that tomorrow.

 

[MoC]

Okay! Here is what I did today. Cleaned all ground connections. bypassed three wires installed by making up three new wires. Removed the field wire off the generator and no change. Pulled battery, voltage regulator, and generator. Had all three tested. There are no bad cells, voltage regulator tested okay, generator outputting between 5 and 10 amps, voltage out of generate is 6 to 8 volts.

Reinstalled everything. Battery was at 6.2 with engine off. Polarized the generator. With engine running I am reading anywhere from 7 to 8 volts constantly going to the battery.