My Battery is draining on 8n -- Wiring correction maybe?

I have a new battery in my 8n and the battery is being drained when it is off. I was curious how the battery should properly be wired so it doesn't get drained and does get charge?

Thanks!
 
Here is a diagram... I thought is attached before.
a163477.jpg
 
The advice I was given as a starting point..


From Bruce
Google "wiring diagrams JMOR " and find the diagram that fits your tractor.

Each 8n is it's own animal in many ways.. Pictures help these guys to help you... Lots of times someone will notice something in a pic that has been over looked..
Good luck.
 
(quoted from post at 13:14:33 06/20/17) I have a new battery in my 8n and the battery is being drained when it is off. I was curious how the battery should properly be wired so it doesn't get drained and does get charge?

Thanks!
I would take the alternator to a shop and have it checked out.
 
Svrunyan,Your one wire alternator could be draining the battery overnight.Disconnect the power lead from the alternator overnight and check if the battery is still up the next day.
 
Disconnect alt and put a test lamp clip on that wire, and probe to alt charge lug. IE, test lamp in series.

If lamp dimly glows, alt is bad and leaking.
 
I agree with all above posted .... A bad diode in the altanator could cause it. Have it checked.

If you bring it to a auto place to have it checked make sure you tell them it's a tractor not a car. Tractor altanator looks just like a car one but the difference is the tractor altanator field excites and charges at only 500 rpm whereas automotive alt begins charging at 1000-1200 rpm.

One last tip... I put battery shutoff switches in all my tractors. Helps with long term storage and can help prevent a battery drain if you have a problem. You have to get a heavy duty one though that is rated for a lot of cranking Amps ... Not the Mickey Mouse shutoff switches they sell at HF.... I get mine it's a knife type switch from NAPA.
 
(quoted from post at 19:04:06 06/20/17) I agree with all above posted .... A bad diode in the altanator could cause it. Have it checked.

If you bring it to a auto place to have it checked make sure you tell them it's a tractor not a car. Tractor altanator looks just like a car one but the difference is the tractor altanator field excites and charges at only 500 rpm whereas automotive alt begins charging at 1000-1200 rpm.

One last tip... I put battery shutoff switches in all my tractors. Helps with long term storage and can help prevent a battery drain if you have a problem. You have to get a heavy duty one though that is rated for a lot of cranking Amps ... Not the Mickey Mouse shutoff switches they sell at HF.... I get mine it's a knife type switch from NAPA.
saw it on the internet, so it must be true", right?
 
No smarta$$... Did not see it on the Internet. I have a guy who re builds alt's and starters, he had been doing it for over 50 years.

That's what he told me, guess he knows what he is talking about if he has been rebuilding the things for over 50 years.

But hey what do I know I'm just a dumb farmer!
 
(quoted from post at 19:38:23 06/20/17) I just put one off of a car on my 8N, works great :wink:

Me Too . I don't think I have ever read on this forum that someone actually had a problem with an alternator not charging at low rpm . I have seen the theory of the rpm discussed though .

If your alternator rpm needs to run 1000 - 1200 and it is spinning twice as fast as your crank then unless you get the motor to idle at 400 rpm I don't think there is a real problem ? My idle is 7 - 800 ish and the idiot light goes off when my motor starts .
 
(quoted from post at 20:38:23 06/20/17) I just put one off of a car on my 8N, works great :wink:
t what alternator rpm it begins charging has to do with the VR and even though there are a dozen or two variants, none are sold as 'tractor' or 'auto' VRs. As to engine rpm, that will be most dependent on what pulley size is used on the alternator. Doesn't really matter whether "said on internet' or 'heard from someone' or as on CNN & MSNBC, 'heard from a reliable source'.
 
JMOR....

Not understanding what your sayin. We all agree that the internal voltage regulator controls when the alt is charging.

Along the lines of what I was told was that you need to have a alt with a VR in it that is set to charge at a lower RPM.

If that's not the case then you would be able to put the same altanator from a F150 truck into a Maserarti or a Ford 8N tractor ???!!

Does not make sense to me. Ya go to your auto parts store and tell them ya need to buy a alt.... They just don't give you a "universal" one fits all off the shelf.... They will ask you for your make and model and engine type to give you the correct alt for your vehicle.

Go to a junkyard and look around and most vehicles have Diffrent sizes or kinds of alt's in them.... Every single vehicle does not all have the same alt in it.

As to running a car or truck alt on a 8N, asked my guy about it and he said it will work fine in the short run for a while with no adverse effects but long term use will mess with the battery shortening it's life.


Don't understand why when you drop a alt off to be rebuilt why they ask you what's it going in if it does not matter like your saying.

Just trying to get some education on this. Completely Diffrent from what I've been told, and by folks who know lots more about this stuff than I and work with alt's re building them everyday. I guess they been doing it wrong for over 50 years?!
 
If you want a 10-SI to start charging at a lower rpm, the best/easiest thing you can do is to use a standard 3 wire connection & skip the one wire units. This way, your battery supplies the excite current and not the tiny generated current resulting from a very small residual magnetism of the rotor, which often needs substantial speed in order to kick in.
 
Hi and thanks everyone!

I do have a question for JMOR but it appears overall that I need to have the alternator checked and possibly replaced. My question for JMOR
would be whether this diagram appears correct for a 3-wire alternator hookup?

I will check the alternator and re-wire for the 3-wire setup if this appears to be correct.

Thanks again. This is a great discussion group. Always very helpful.
a163551.jpg
 
It wouldn't do any good here to ask the guy behind the counter for
a Ford 8n alt. They would not have a listing for an 8n.

Anytime I ever used a new alt for a conversion. I simply asked for
a Delco 10Si with a certain clock position. Part houses will not
have a listing for alt conversions.

Alternators are stupid. They can't tell if they are on a John
Deere combine or a Ford 8n. The last conversion I did. I removed
the alternator from a 76 GMC with a 350 and put it on a 1955
Farmall 300. It worked just fine. You can in fact take an alt off
an F150 and put it on an 8n Ford.

One wire alternators sometimes work and sometimes don't at low
rims. The difference is the size of the pulleys. I have converted
tractors from one wire to three wires because the owners hated
having to rev the engine to get the alt to charge.

The last 8n I put a 6v Delco one wire. I ordered a special smaller
diameter pulley to spin it faster.

I use to rebuild Delco 10SI alternators back in the 80's and 90's
when every tractor,combine, and truck used a 10SI. The only
internal part that was different was the stator. The amount of
copper wire in the stator determines if it is a 30,60 or 70 amp.
 
(quoted from post at 08:29:12 06/21/17) Hi and thanks everyone!

I do have a question for JMOR but it appears overall that I need to have the alternator checked and possibly replaced. My question for JMOR
would be whether this diagram appears correct for a 3-wire alternator hookup?

I will check the alternator and re-wire for the 3-wire setup if this appears to be correct.

Thanks again. This is a great discussion group. Always very helpful.
a163551.jpg
es, with one exception. It needs one of 3 items inserted between the key switched power and alternator terminal #1, so as to prevent alternator from feeding back power to the coil when shutting down, otherwise engine will keep on running when you switch off ignition. 1) a resistor ( GM used 10 Ohm, 6.25Watt resistor in parallel with "idiot lamp" , 2) a diode with current rating of 3amperes or more, 3) a small lamp ( many will work, among the popular is the 194 used in side marker lights).
 
Your rebuilder guy must have been doing it wrong for 50 years.

no reaso why a 'truck' alternator will hut the battery on a tractor.

that alternator doesn't know what it's installed in.

it sees an electrical load.. that's it.

it's internal vr will vary field current to produce charge as needed within the constraints of the alternator. that means it
charges the battery and supplies power to things like ignition and lamps.

A gm 10 Si al doesn't know if it's installed in an old junky gm vehicle.. or a tractor.

your guy telling you that it will shorten the battery life is simply BS'ing you..

Ask him when he got his engineering degree...
 

Hi JMOR:

So, ironically, I didn't mention this previously or diagram it because I didn't think it mattered, but I guess it does. I do have a bulb connected between terminal #1 on the alternator and what I call terminal "B" on the resistor block (see diagram). So based on your recommendation, does this sound correct?

1) When I turn the key "on" the bulb lights, and 2) after the tractor starts the light goes out and tractor remains running. 3) When I turn the key to "off", the light still stays off and the tractor shuts off -- sound right?

The last question I have is which I just now noticed. My Ampere meter jumps to +30 after the tractor starts and steadily (within a minute) drops to about 4-5 amps past zero. Would this then be an indicator my alternator is bad as well?

Thanks!

49868.jpg
 
You describe normal operation of the alternator.

That doesn't mean that the alternator is not the source of the power drain.

souNdguy explained how to test for this when he said "Disconnect alt and put a test lamp clip on that wire, and probe to alt charge lug. IE, test lamp in series. If lamp dimly glows, alt is bad and leaking."

'Course, the power drain could still be something else...
 
(quoted from post at 16:06:51 06/21/17) You describe normal operation of the alternator.

That doesn't mean that the alternator is not the source of the power drain.

souNdguy explained how to test for this when he said "Disconnect alt and put a test lamp clip on that wire, and probe to alt charge lug. IE, test lamp in series. If lamp dimly glows, alt is bad and leaking."

'Course, the power drain could still be something else...
vrunyon, I'll ride with soundguy & Jim.
 
(quoted from post at 16:04:06 06/20/17) I agree with all above posted .... A bad diode in the altanator could cause it. Have it checked.

If you bring it to a auto place to have it checked make sure you tell them it's a tractor not a car. Tractor altanator looks just like a car one but the difference is the tractor altanator field excites and charges at only 500 rpm whereas automotive alt begins charging at 1000-1200 rpm.

One last tip... I put battery shutoff switches in all my tractors. Helps with long term storage and can help prevent a battery drain if you have a problem. You have to get a heavy duty one though that is rated for a lot of cranking Amps ... Not the Mickey Mouse shutoff switches they sell at HF.... I get mine it's a knife type switch from NAPA.

I've got some news for you. Those mickey mouse Harbor Freight switches work. My battery used to run down after sitting for months with the tractor not being used. I finally put in one of those cut off switches and it doesn't run down anymore.

But of course if you have a problem with it running down quickly you really should find the problem and correct it.
 
Thank everyone. It looks like I've got some homework. A lot of good info.

Thanks for being patient with the newbie so 8Ns.
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top