24 volt starter problems

[John T]

Despite all the fun 24 volt chat below, (fun for us sparkies even if others were bored to tears) I didnt see this issue raised so here goes. I had a good supper (fish fry n beer at American Legion Hall then Dairy Queen) and now all rested lol ready to go back to work..

When giving workshops or seminars or when in the tractor business I often got the question: "I have a 24 volt Deere and one of the batteries keeps going down yet other one doesnt hmmmmmmmmmmm whats wrong"

I tell them one among many possibilities (if all else and batteries are okay) IS DUE TO THE STARTER

Then they say "But I thought the starter was a 2 terminal 24 volt ELECTRICALLY ISOLATED FROM FRAME GROUND DEVICE" To which I respond "YES it is weedhopper but heres a scenario under which a starter problem can cause one battery to discharge.

Its possible soft copper dust from the brushes has accumulated to a point that theres an internal shorting electrical conductive path through the copper dust from the internal connector to frame ground AND IF THAT HAPPENS ONE BATTERY CAN TRICKLE DISCHARGE

That can still happen DESPITE THE FACT the starter isnt supposed to have any electrical connection to frame ground AND HERES HOW N WHY

On the 24 volt starter (unlike a 12 volt with only one stud and case ground serves as the other) there are 2 big post/studs, one to the + grounded battery and the other to the - grounded battery (remember where the batteries join in the center thats also bonded to frame ground via a small jumper wire) so theres 24 volts to the starter once the solenoid closes.

Nowwwwwwwww imagine inside copper dust (off brushes) has accumulated so theres a shorting path from one of the internal post connections to the steel frame portion of the starter THAT CAN CAUSE A BATTERY TO DISCHARGE becauseeeeeeee the other post of that battery is also tied to frame ground at that center tie point

Sooooooooo if the starter has some age on it and one of the batteries is discharging and all else is okay, CHECK THE STARTER FOR A COPPER BRUSH DUST SHORTING PATH

Hope this helps, best wishes n God Bless yall and thanks to all who helped in this neat discussion, hopefully we helped answer some questions

Ol John T and all

 

[teddy52food]

That will cause the battery on the right side to go dead. Where I used to work, the other guy did most of the electrical work. He would also rewrap the field windings cause they were shorting to the case. So it wasn't only the dust that caused trouble. When that 24 volts hits those windings there is an equal and opposite reaction to the action , which can move the winding enough to wear through the insulation.

 

[Cliff Nelson]

The reason that the brush dust and chaffed insulation causes the RH battery to discharge is because the armature and field are always "hot" with 12 volts in relation to the frame from the RH battery. The short caused by the dust or poor insulation is not enough to burn the fuse or fusible link at center point of batteries but a couple amps will discharge the battery over time. The LH battery goes to the solenoid and not to the starter until you try to start the engine. On a 12 volt system you don't see problems with brush dust because the starter windings are not "hot" except when cranking. Moisture inside the starter also causes the same problem (can be caused by pressure washing or sitting out in wet weather).

 

[M.J.P.]

John T. I have a 4010 with the 24 v system and on the small ground wire on the battery it has a inline fuse. Does this wire need to be fused?
sometimes it will blow the fuse. thanks

 

[Tx Jim]

When the 24 v tractors were first upgraded from the 2 ground cables to frame to the batt cable that crossed over to both batteries rear post just a small ground wire was used. Later when the circuit breakers at the starter kit was furnished the kit contained an inline fuse holder & fuse. I think the fuse is better because if one gets a short it will help protect the wiring harness better than just a solid ground wire. Kit had a AR47713 FUSE 1 20 AMP, MDL which I was a medium delay fuse

 

[John T]

EXCELLENT QUESTION, see Tx Jims very informative post above..

My comments:

Of course it will "work" unfused when I used those tractors and sold them most were NOT fused

HOWEVER I agree with Tx Jim, if fused it can sure protect the wiring should an overload condition occur.

NOTE: In the 24/12 system ifffffffff each battery load is perfectly balanced with say lighting loads, most of the series loop 24 volt current can flow out of the A lights over to the B lights (12 + 12 across 24 volts) and NOT have to flow in the little series bond frame ground jumper. That means even if the to frame ground jumper were broke or its fuse blown THE LIGHTS CAN STILL WORK. HOWEVER if the center tie bond to frame ground is open and the lights are operating in the 24 volt series loop but one circuits lights (A or B) has an open then none of the lights work......WITH the mid tie point frame ground in place and the seperate but opposite grounded 12 volt circuits intact EITHER side can still work even if one circuit has an open....

Thanks, in helping you with your questions it forces me to use my old dusty rusty engineering brain lol and I also learn in the process. Years ago I turned down giving the 24 volt Seminar cuz I was already giving 3, Mag, Ignition Systems and Charging Systems and didnt like the 24/12 system so Tom 43 stepped up to the plate and gave it, he (and Buick) does a good job and is a better teacher then I am. Heck you guys have forced me to review all this and I may start givign the 24 volt one wooooooooo hooooooooooo THANKS YALL

John T

 

[John T]

WOW great information to which I agree. When I used bought n sold many of those tractors most were NOT fused but Id like it there to protect things if an overload occurred.

By your questions and help and my having to think through all this stuff Im also learning here and I think we have helped some of the other fine gents

John T

 

[John T]

Thanks for the great information, as I posted above in helping others here were also helping ourselves. When I answer a question I end up learning my self YALL ARE GREAT

I agree with you also, the one battery isnt connected to the starter because of the open solenoid contatc. HOWEVER that other battery has the big cable direct live and hot to the starter and thats the battery that gets discharged via the short to frame ground YUKKKKKKKKKK

Thanks, John T

 

[John T]

Good information Teddy, Thanks. Yes I knew only the battery that was hot to the starter got discharged and the other dont because the solenoid is open but Im never sure of the right left which is which lol

John T

 

[Kerry50]

I have to jump the right hand battery on my 4020 when i first start it in the morning. After that it will start good the rest of the day. Is this my problem? Thinking it is. Would disconnecting the fuse from the left hand battery to frame keep it from draining the right hand battery over night?

 

[LarrySTN]

I've worked on many 24 volt 4020's over the years. The main electrical complaint was the right battery going dead, if the tractor sat for more than a week or two. Usually the "leak" is only a few hundred milliamps, but over the course of time will kill the right battery. If one doesn't want to spend the money on the starter, pulling the fuse (when tractor is not in use) on the small wire to frame will keep the right battery from being discharged.

 

[John T]

YES as posted immediately above iffffffffffffff ?????????????? thats the cause of your discharge????? If the fuse is open that breaks the current flow path so the battery cant discharge via the copper dust

Its not all that hard to remove and disassemble the starter and clean all that up perhaps

John T

 

[John T]

Thanks for that insight. When I ask or even answer a question on here I end up also learning myself

Surely we have helped the other fine gents here learn in all these 24/12 discussions?

If we had Tom 43 and Buick Man video copy their workshops and coupled it with all this great info WE'D HAVE IT ........

John T Never too old to learn

 

[John T PS]

You have heard the old proverb: Give a man a fish feed him for a day, teach him how to fish feed him for a lifetime, well heres a perfect example......

Below there were two different answers posted to a question, heres the link to a method I came up with to determine which is correct its sooooo simple and easy actually

http://www.ytmag.com/cgi-bin/viewit.cgi?bd=jd&th=432512

John T Never too old to learn
12 or 24 volt Solenoid

 

[teddy52food]

A solinoid wired between the right hand battery and the case stud would correct that. You guys that are taking out the fuse in the mid point wire should put a charger on that right hand battery to bring it up once in a while too. Even when running and charging, that battery has a drain on it & maybe doesn't get fully charged.

 

[Mike M]

Others did mention the field coils,but I also wanted to bring it up because this is a BIG problem area to watch for. A bigger problem on ones that sit out or get washed alot. The moisture can let them burn through to the housing.

Ok now I heard a different ending version of that proverb. Teach them to fish and they will sit around and drink beer all day! !!

 

[John T]

Hey I see no problem with the fishing and beer Mike lol

John T