Thanks to John Deere Forum on 24 Volts

I want to thank the members of the John Deere Forum who read my lengthy 24 Volt Explanation. As I said we just scratched the surface of the topic. I want to apologize for the lack of pictures, schematics, and diagrams. My wife is out of town and I do not know how post pictures. My Gathering of the Green Seminars are in color and on Powerpoint thanks to my more skilled wife. The system is much easier to describe with pictures and drawings with arrows to show current flow in various parts of the circuitry.

If you are a tractor lover, the Gathering of the Green is spectacular and the most exciting event I have ever attended. We had roughly 3 thousand attend two years ago. There are some great seminars on painting, hydraulics, carburetion, and all aspects of restoration. Some of the classes such as ignition, starting and charging, painting and carburetion, can apply to all brands of tractors as well as older cars, pickups combines and trucks. Corky Groth's tune-up presentation which is full of information and humor is worth the trip in itself.

I will be teaching seminars on 24 Volts, Distributor Ignition, and another on General Electrical Problems including charging and starting. Once again Thanks for reading!
 
Even though I do not like the 24 volt system I found your post and the others very informative. There is alot of good info on this site and I learn alot from the people who post here. Thanks for your time and effort. I also found the post below about coils very informative. My weakest point is wiring. I find I can make a new harness with a delco alt. easier than I can trouble shoot one with lots of problems. Tom
 

I wasn’t going to attend GOG next year but now maybe I should . Have to make sure that that the 24V explanation doesn’t get messed up again.
there is a two part article in GM where the system was described as having a 24V positive ground .
Should have seen the looks of disbelief with my 24V display at the NY Expo. People could not believe that the starter would operated just connected to the cables without being bolted to the engine block. Motoring the generator at two different speeds was declared to be magic .
To be honest the person with the best understanding of the 24V system is Jim at Agri-Services . Used one of his 1st rate wiring harnesses for the demo.
 
(quoted from post at 19:24:40 11/01/17) I want to thank the members of the John Deere Forum who read my lengthy 24 Volt Explanation. As I said we just scratched the surface of the topic. I want to apologize for the lack of pictures, schematics, and diagrams. My wife is out of town and I do not know how post pictures. My Gathering of the Green Seminars are in color and on Powerpoint thanks to my more skilled wife. The system is much easier to describe with pictures and drawings with arrows to show current flow in various parts of the circuitry.

If you are a tractor lover, the Gathering of the Green is spectacular and the most exciting event I have ever attended. We had roughly 3 thousand attend two years ago. There are some great seminars on painting, hydraulics, carburetion, and all aspects of restoration. Some of the classes such as ignition, starting and charging, painting and carburetion, can apply to all brands of tractors as well as older cars, pickups combines and trucks. Corky Groth's tune-up presentation which is full of information and humor is worth the trip in itself.

I will be teaching seminars on 24 Volts, Distributor Ignition, and another on General Electrical Problems including charging and starting. Once again Thanks for reading!
5525.jpg



You are most welcome my friend Tom. I'm glad I, along with others, especially TxJim and Buick (gave an excellent 24 volt seminar at Two Cylinder Expo) and Bob and Dave and ET (I consider as 24 volt experts and the Go To guys on this topic) were able to help you out. Still, its hard for the untrained to understand let alone troubleshoot the system as its a rats nest under the dash and any color coded wires are faded grrrrrrrrrrrr.

Since you were unable to post a wiring diagram, I have attached one for your and the others benefit. Of course this is NOT new generation where a wire could be used to replace use of the iron frame as a return current path HOWEVER the design and theory of the 24 volt system is still similar where the Starter Motor and Generator are two wire isolated off frame (NOT POS GROUND) yet the 12 volt loads like lights and gauges etc are fed 12 volts (as the diagram shows and how they were wired) from EITHER the A or B battery banks, one of which is POSITIVE GROUNDED the other NEGATIVE GROUNDED as shown by the center tie point frame jumper wire discussed below. If you study the diagram you see the loads are balanced as the A feed up to the light switch powers some lights and the other lights are fed off the B feed, one bank of course has its - to frame (NEG Ground) the other its + (POS Ground) to frame.

NOTE THAT JUMPER WIRE WAS THERE FOR A REASON AND SHOULD BE KEPT IN PLACE AND IF YOU EVER HAVE A PROBLEM WHERE SOME 12 VOLT LOADS WORK AND OTHERS DONT CHECK THAT FRAME JUMPER WIRE !!!!!!!!!!!!

OF COURSE as I'm sure you well understand Tom, if two sets of 12 volt lights were wired in series across 24 volts BOTH WOULD WORK FINE even with no frame ground jumper wire and even if in place it wouldn't draw current. HOWEVER if one burned out neither would glow grrrrrrrrrrr yet with the frame ground jumper wire in place as designed and they were built one (A or B fed, Pos or Neg ground battery bank fed) that problem is eliminated. ALSO if a device such as for example a fuel gauge or some sort of relay etc is needed that requires 12 volts IT HAS TO BE FED FROM ONE OR THE OTHER OF THE BATTERY BANKS (The A or B, Pos or Neg grounded) because 24 volts would burn it up grrrrrrrrrrr and where is that 12 volts ????????? Its between one A battery or the other B battery 12 volt feeds (one of which has its POS to frame, the other has its NEG to frame) that run up to the light switch.

BUT REMEMBER the two wire 24 volt isolated off frame ground Starter Motor and Generator DO NOT USE THE FRAME OR NEED THAT CENTER FRAME GROUND JUMPER

ITS ONLYYYYYYYYYYYYYY the 12 volt loads that MAY (may not need if wired in series across 24 volts as can work with NO jumper whatsoever as long as both are conducting) utilize the center frame jumper as the return current path if no 24 volt series path exists) AND ALSO a 12 volt load like a 12 volt gauge or relay etc needs ONLY 12 volts and it has to get 12 volts from either the A or B feeds, one of which is POS grounded the other is NEG grounded as JD diagrams show and how they were wired from the factory. YOU CANT POWER A 12 VOLT LOAD WITH 24 VOLTS and 12 volts is available off the A or B feeds AGAIN sure you can power two equal 12 volt loads off the series 24 volts WITH NO JUMPER REQIIRED AND IT DRAWS NO CURRENT.

EVEN IF YOU SAY ITS OVERSIMPLIFIED I think this is an excellent place to copy and paste the 24 volt portion of the Official John Deere Service Bulletin No 268 as it describes what I just explained above EVEN IF SHORT N SWEET NO ONE SAYS ITS INCORRECT !!!!! and in my years of farming and selling 24 volt JD tractors ITS HOW THEY WERE WIRED !!!!!!! AND ITS HOW THEY WORKED AND CURRENT ALL FLOWED IN THE RIGHT DIRCECTION This is DC NOT AC duhhhhhhhhhh lol



THE electrical system used on John Deere Diesel ( E l e c t r i c Cranking) Tractors is a 24-volt split-load system using 24 volts for the cranking and charging circuits and 12-volt circuits for the lighting and accessory load.

Figure 41A is a schematic draw-ing of the system

A 24-volt generator, controlled by a 24-volt regulator, supplies current to carry the electrical load and charge the four 6-volt batteries connected in series which supply current at 24 volts for cranking the engine. The cranking circuit and the charging circuit are two-wire circuits- the entire circuit is carried through wires and no part of it is grounded to the tractor frame. Two 12-volt circuits are obtained by installing a ground wire between the second and third batteries in the circuit and the tractor frame. Also, the combination switch is in reality two separate switches enclosed in a single housing and operated by a single lever. One of these switches controls current to approximately l/2 of the load, the current being supplied by two of the batteries. The other switch controls current to the remaining 1/2 of the load, current being supplied by the two remaining batteries.


SOOOOOOOOOO THERES WHAT JOHN DEERE HAD TO SAY AND SHOW IN DIAGRAMS SO DONT TAKE MY WORD FOR IT, LOOK AT HOW THEY WERE DESIGNED AND BUILT AND WIRED AND OPERATED FINE AND HOW THAT CENTER FRAME TIE JUMPER WIRE BONDS THE NEG OF ONE BATTERY AND THE POS OF THE OTHER TO FRAME AND HOW A AND B (one Pos Ground other Neg Ground) 12 VOLT FEEDS RUN UP TO THE SWITCH TO POWER LIGHTS AND GAUGES IN AN ATTEMPT TO BALANCE BATTERY LOADS. NOTE a wire could be used instead of the iron frame as the return current path but still its 12 volts off one battery or the other to feed one set of 12 volt lights or the other regardless if wire or the frame serves as the return current path.

CLOSING that's how John Deere describes the 24 volt system and how official John Deere diagrams and publications and Service Bulletins describe the system and how they were shipped from the factory and THAT CENTER JUMPER TIE WAS INSTALLED SO I SUGGEST YALL LEAVE IT IN PLACE EVEN IF ALL WERE PERFECT AND NO LOADS WERE BURNED OPEN SOME DEVICES CAN STILL WORK.

If anyone dislikes the JD system or argue their diagrams or builds were NOT right or its NOT as they (not my words) described above in Service Bulletin and their published diagrams are wrong, take it up and argue with them not meeeeeeee lol

I WANT TO THANK MY FRIEND TOM FOR ALL HIS TIME AND EFFORT I CERTAINLY APPRECIATE IT. In all these discussions we may have bored the others to tears lol but we have learned and benefited from others experience and knowledge and shared and that's whats its all about

GOD BLESS YOU ALL AND TOM AND THANKS FOR YOUR PARTICIPATION AND FOR READING ALL THIS, I sure hope it helped THATS MY GOAL HERE

John T Retired Electrical Engineer
 
Mr. T, I see that my attempts at conciliation came to nothing as your are back to your mocking, patronizing old self. Obviously you and your "Go To Guys" with the exception of Dave and Bob are much more interested in protecting your egos than learning ANYTHING! I especially object to your "HELPING ME OUT" statement. I learned ABSOLUTELY nothing about 24Volts from you, Tx Jim, or Buick and Deere(the only person in North America more arrogant than yourself). I learned the system by asking countless questions, teaching automotive electricity for 23 years, taking physics classes, and consulting physicists and engineers before publishing and working with the system for 53 years as well as working in a John Deere Dealership. I did this BEFORE I ever heard of you and the "Go To Guys"(that would be a good name for a band). I am usually pretty easy going but I owe it to my hundreds of students and readers to maintain my credibility. I wouldn't want people to travel all the way to Davenport, Iowa to listen to a quack! Please spare me any more hypocritical "apologies." Disagreement on technical issues but mocking, patronization is another! My mind is open as I did learn a few things from Buckeye Al and Bob, but certainly not from you or the "Go To Guys."
 
Buick and Deere, you are certainly welcome to come to my 24 Volt class at Gathering of the Green provided you come to learn. However, any attempt to disrupt the class or keep me from "messing things up." will meet with your prompt eviction by both myself and the sergeant at arms!
 

I suppose if you feel the need to toss me out for laughing, feel free to try.
Btw way when and why did your drop the 24V positive ground portion of your beliefs ?
 
Sorry you feel that way Tom, I intended no harm, my post was ONLY to explain the John Deere diagrams and their Service Bulletin (it was a purely TECHNICAL post) and NO ill feelings. Best wishes and God Bless you and your family. I still appreciate all you do, thanks again for your help.......


John T
 
(quoted from post at 12:18:09 11/02/17)

I learned ABSOLUTELY nothing about 24Volts from you, Tx Jim, or Buick and Deere(the only person in North America more arrogant than yourself). I learned the system by asking countless questions, teaching automotive electricity for 23 years, taking physics classes, and consulting physicists and engineers before publishing and working with the system for 53 years as well as working in a John Deere Dealership. I did this BEFORE I ever heard of you and the "Go To Guys"(that would be a good name for a band).

Tom
I haven't attempted to teach you anything about the JD 24 volt system except I've known for many yrs that the system is NOT positive ground & the wire that splits the batteries is very important!!!!! Is it true that you were once a history professor or is that just a RUMOR? If it's true you've been a very busy person the last 53 yrs!! I hope you have a wonderful time at Davenport.
Jim
 
Do they REALLY have a sergeant at arms at GOG? That seems to be going a little too far for a John Deere "info" gathering. I also have a BS in electrical/electronics engineering (obtained in 1967) and have followed these forums for many years. I do understand the 24 V system on JD tractors and agree with JD's technical bulletin and could teach the subject. A friend has a 730 diesel with the original system and four 6 volt batteries that I've studied a bit. Overall this is NOT as complicated as some would make it out to be.
 
I once found myself trying to explain the JD 24 volt system to a feller who owned a 3010D. We were struggling which surprised me because his day job was that of an electrician! I quit talking for a while & just thought, how else can I explain this? I suggested we try this explanation which may help some reading here.

Many may be familiar with house wiring and so maybe viewing the tractor more like the house might help?

That little tie wire between the batteries that goes to the frame is the tractor's equal to the house's NEUTRAL! Everybody knows how important the neutral is to the house right? That "pig tail" to the frame is just as important to the tractor as the neutral is to the house! The right battery lead to the starter's side post is like one 120 volt AC leg & the left battery lead going to the solenoid is like the OTHER 120 volt AC leg. Those two legs going to the starter & the solenoid are out of phase (opposite in polarity) from each other just like the two 120 volt legs of the house. The only difference beyond that is they're each 12 volts DC in the tractor instead of 120 AC as in the house! They meet at the starter presenting it with 24V just like the two 120V legs meet in the house's main disconnect/breaker box making either 120v (either leg to neutral) or 240v (leg to leg) available.

Other than that it's all the same right down to the need to balance the loads on each 120 volt leg in the house as much as possible.

He understood it perfectly after that!

Just as surely as all things get seemingly "stupid" in the house when the neutral goes open, so too on the 24 volt JD when that little "tie wire" wire goes open. You've lost yer neutral & things get "peculiar"! Some lights burn brightly while others may be dim. Electric gauges may read wrong, backwards or not work at all. Light bulbs may even burn out.

Dust inside the starter is a fault path to ground that consumes power at all times but not enough to open a breaker! (I know, there isn't one present to be opened on the tractor like GFCI breaker would on the house.) This "dust/moisture fault path" is what chronically drains the right battery! Jumper cables on the right battery are not particularly effective because the jumper cables (in the JD 24 volt system) have to carry ALL of the starting current instead of only contributing in parallel like when jumping a 12 volt car or truck. That's why it works best to charge the right battery back up & THEN he's more likely to start. If the right battery is flat out dead jumping it doesn't work particularly well unless the jumper cables are VERY good cables!

Does that help?
 
Go back to what you wrote on Oct 30 and read carefully the second paragraph. Then explain the phrase (quoting) "each have a dedicated wire back to the positive terminal of one of the batteries." These wires can't both go back to positive of batteries - one has to go to negative of a battery.
 
55-50, Good question. It is best to visualize the positive battery terminal whose cable hooks to the isolated terminal on the barrel of the starter as ground(the other heavy cable goes from the negative terminal of the other battery to the solenoid), Ground can be defined as a point of zero voltage potential. The generator, voltage regulator, hold in winding of the solenoid, and the starter itself are all isolated from the tractor frame. All of these are hooked together with a dedicated wire back to the positive terminal of the battery which we are calling ground. This is what is unconventional about the system. As you astutely observed there is also a negative wire going from the A1 generator terminal to the ARM terminal of the regulator. When running, the ARM terminal of the regulator connects internally to the cut out relay to the BAT terminal and eventually to the negative terminal of the other battery. I didn't mention this negative wire because it is conventional and just like the circuitry in a gas tractor or car or pickup with a generator. I assumed this was self explanatory as I didn't want the explanation to go on forever. I hope this answers your question.
 
(quoted from post at 23:38:25 11/02/17) It is best to visualize the positive battery terminal whose cable hooks to the isolated terminal on the barrel of the starter as ground(the other heavy cable goes from the negative terminal of the other battery to the solenoid),

You still can't understand there's not suppose to be a ground at the starter. You also failed to answer if you ever taught history.
 
You still can't understand there's not suppose to be a ground at the starter. You also failed to answer if you ever taught history.

I agree with Jim. Starter and generator are totally undependant.
The big Delco starter also used in many other applications is almost always not grounded. Even in 12V applications like 5020 and 6030. If you do not connect the negative to the starter negative post, it will never turn!

Overall, that circuit is quite simple and I don't see why you would need ton of classes on it:
- The starter and generator are 24V and are wired as such and are not connected to the chassis.
- The lights are 12V wired in series and supplied with 24V, with the frame making the connection between them. In that case, assuming same lights are used, there is 0 current in the middle wire.
- For the cases when farmer Bubba (talked out before) replace lights with different left and right, or tractor has burned bulbs, Deere has put a small wire between both batteries and the frame that is there to ensure that there is always 12V between each lights. This allows as well for the system to run on one light only if one light was burned and levels the tension on the frame.
Without the middle wire, if you put a different bulb left and right, you can easily have a system that is -8V + 16V (frame to each side of switches), instead of -12V+12V.
- And on top of that, the middle wires allow to run 12V instruments and sockets, altough the system is not able to charge them if only that was used.
All the above is basic physics taught in high school.
 
Good info 860, you say

"I agree with Jim. Starter and generator are totally undependant."

That's what the official John Deere publications and wiring diagrams show and how they were built IE NOT Positive Grounded


"Overall, that circuit is quite simple and I don't see why you would need ton of classes on it"


EXACTLY if you look at John Deere Service Bulletin and the John Deere Service Bulletin No 268 I POSTED TWICE BELOW it shows and explains it PLUS that's how the tractors came from the factory.

John Deere's sentiments which I subscribe to is that center tie frame jumper (One battery POS Ground the other NEG Ground) wire is there for a reason KEEP IT THERE !!! and if there ever a problem where some 12 volt loads work and others don't CHECK THAT JUMPER GROUND WIRE

Take care and best wishes to you and all here and all who contributed.

John T
 
I didn't intend my entry to be a question. Just wanted to point out an error in your writing. Do you get paid to teach this stuff at GOG?
 
(quoted from post at 09:10:07 11/03/17) Good info 860, you say

"I agree with Jim. Starter and generator are totally undependant."

That's what the official John Deere publications and wiring diagrams show and how they were built IE NOT Positive Grounded


"Overall, that circuit is quite simple and I don't see why you would need ton of classes on it"

With all this talk about the 24volt systems I have a question that may not have been addressed as of yet. It concerns the right battery drain caused by dust in the starter. I realize the best way to stop this drain is to keep the starter clean but allowing for slothfulness of some people (me) , if the center tap wire on the battery was opened and closed at the same time the ign. switch was turned off and on would this not serve to solve the drain problem? My experience is limited to DC circuits in Power substations where 134, 48 , 24 and 12 volt Dc was used to power various motors and control circuits. These various voltages were supplied by one or more sets of Batteries that were just tapped at different cells to provide the appropriate voltage. Much the same as the 24 , 12 volt systems on JD just much bigger. just as a side none of these voltages were ref to GND they all had + and - .
 

It's been a long time since I repaired a 24 volt problem but IIRC
sufficient brush dust in starter will drain the RH battery with or without little ground wire attached. Although when thinking about it one would think the ground wire would need to be intact & attached for drain to transpire.
 
(quoted from post at 19:23:13 11/02/17) I once found myself trying to explain the JD 24 volt system to a feller who owned a 3010D. We were struggling which surprised me because his day job was that of an electrician! I quit talking for a while & just thought, how else can I explain this? I suggested we try this explanation which may help some reading here.

Many may be familiar with house wiring and so maybe viewing the tractor more like the house might help?

That little tie wire between the batteries that goes to the frame is the tractor's equal to the house's NEUTRAL! Everybody knows how important the neutral is to the house right? That "pig tail" to the frame is just as important to the tractor as the neutral is to the house! The right battery lead to the starter's side post is like one 120 volt AC leg & the left battery lead going to the solenoid is like the OTHER 120 volt AC leg. Those two legs going to the starter & the solenoid are out of phase (opposite in polarity) from each other just like the two 120 volt legs of the house. The only difference beyond that is they're each 12 volts DC in the tractor instead of 120 AC as in the house! They meet at the starter presenting it with 24V just like the two 120V legs meet in the house's main disconnect/breaker box making either 120v (either leg to neutral) or 240v (leg to leg) available.

Other than that it's all the same right down to the need to balance the loads on each 120 volt leg in the house as much as possible.

He understood it perfectly after that!

Just as surely as all things get seemingly "stupid" in the house when the neutral goes open, so too on the 24 volt JD when that little "tie wire" wire goes open. You've lost yer neutral & things get "peculiar"! Some lights burn brightly while others may be dim. Electric gauges may read wrong, backwards or not work at all. Light bulbs may even burn out.

Dust inside the starter is a fault path to ground that consumes power at all times but not enough to open a breaker! (I know, there isn't one present to be opened on the tractor like GFCI breaker would on the house.) This "dust/moisture fault path" is what chronically drains the right battery! Jumper cables on the right battery are not particularly effective because the jumper cables (in the JD 24 volt system) have to carry ALL of the starting current instead of only contributing in parallel like when jumping a 12 volt car or truck. That's why it works best to charge the right battery back up & THEN he's more likely to start. If the right battery is flat out dead jumping it doesn't work particularly well unless the jumper cables are VERY good cables!

Does that help?

First off I am going to say I don't just have a green tractor but I am pretty green on its electrical system - so I hope this question about your post isn't too stupid: In a house system when two legs are put together to get 240 the current alternates. But my 4010 is direct current, correct?
 
(quoted from post at 06:58:44 09/05/21)
Welcome to YT
Yes your 4010 if wired same as from when it left the factory is 24 volt DC

Thanks Jim. I want to restore my 4010 eventually, but have a lot to learn. I just replaced the big cables that go battery to bat and starter to bat. That was so simple and made the tractor crank over like a new machine. That 12 v side is going to take some studying though . . . I am going to have to learn how to read wiring diagrams - definitely don't understand them yet.
 

Now that I have asked my first dumb question, and got it answered, let me ask another basic question about the 12v system side of things for the accessories: It appears that I have one ground wire, a short single that goes from the LH POS post clamp to the frame under the operator platform. Is there another somewhere for negative to frame, or does this one serve both pos and neg 12v legs? And I have seen talk about balancing the system to both batteries - what services as the junction for doing this: starter switch, volt regulator?

I know I could start pulling panels and tracing wires but figure a little advance knowledge may make my stumble along method more productive.
 
one bond from the mid point of the batteries to chassis .
This makes 1/2 the 12V loads positive ground and the other 1/2 of the 12V accessories negative ground .
The starter windings , generator Windings and regulator all float without using an electrical connection to chassis
 

Where does 12 volt get hot from? Does that one little wire serve as a hot and a neutral pathway? Or is it just neutral and the power that supplie the 12 v system is pulled from another location?
 

Doug
The blue & brown wires attached to starter solenoid each supply 12 volts to accessories if wire(item 30) is connected properly. IIRC in the kit this wire also contained an inline fuse holder with a 20 amp MDL(slow blow) fuse part #AR47713 .


mvphoto81445.png
 

Very helpful! If I understand correctly, this 20 amp fuse should be installed in the batt to frame wire - item 30?

My 4010 does not have this, should I install one? Does it matter much?
 

Very helpful! If I understand correctly, this 20 amp fuse should be installed in the batt to frame wire - item 30?

My 4010 does not have this, should I install one? Does it matter much?
 

Does your 4010 have battery connecting cable(item 29) or 2 braided battery cables attached from each rear battery post to tractor frame similar as it came from factory?
 
(quoted from post at 03:37:28 09/07/21)
Does your 4010 have battery connecting cable(item 29) or 2 braided battery cables attached from each rear battery post to tractor frame similar as it came from factory?

It has one insulated bat cable that connect left and right batteries at the batt posts. One small approx 14 GA wire that is connected to the left hand positive post clamp at one end and a frame ground under operator platform at the other end.
 

OK disconnect 14 ga wire on one end & attach 12 volt test light. If light illuminates your tractor has an electrical short to frame. To help find short start disconnecting/reconnecting electrical connections one by one. If light goes out you've isolated the electrical drain
 
(quoted from post at 03:05:32 09/08/21)
JD parts offered a wire with an inline fuse holder with a 20 amp MDL fuse.

I agree about the MDL/slo-blo fuse, Jim, and I think the latest offering from JD Parts was a wire, part number R39713.

I know I have one on the shelf, I need to look and see if it's "fusible link wire" or simply a length of 16 or 18 GA wire with eyelets attached.

xPOWdLw.jpg


Here's a low quality image of the R39713, note there's 2 part ID tags attached to it, the second being what you see low down and a bit to the right on the wire in the photo.
 

This place is great! Other websites charge to get the level of information everyone shares for free on here! Glad for everyone sharing their valuable experience.
 

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