4020 batteries 12/24v

John Achmann · Mar 12, 2016

Hey guys! I'm working on the neighbors 4020. He brought the tractor over with no batteries in it but the cables were there. So after other repairs I installed new batteries, was going to use the cables that were there. Looked in my service manual and confirmed my suspicion. The way the cables were there was not going to be any ground. So I made new cables and installed them as per the service manual. Turned the key on and nothing for 24 volt, I got 12volt as lights work and horn honks. Measured voltage at starter and have only 12 on both lugs. If I measure between the batteries I get my 24 volts but not at the starter. It's like I'm missing a ground for the 24 volts. Any help would be appreciated!What am I missing?

tim s · Mar 12, 2016

Here is a view..

David G · Mar 12, 2016

The starter should have 2 big lugs, one for + and one for -, there has to be 24V between those two if hooked up correctly.

John Achmann · Mar 12, 2016

Hey thanks! My service manual is different then your picture. Does it give you a wire size on the ground for the left battery?

David G · Mar 12, 2016

Should be as big as the others, would assume 0 or 00.

Bob · Mar 12, 2016

"Should be as big as the others"

No.

I have seen a fuseholder there with a 20 Amp slo-blo fuse, or various sizes of fusible links. NOT sure what all was used from the factory.

It needs to be able to "blow" if the +12 or -12 battery cable or the innards of the starter or charging system short to the chassis.

Here's what DEERE currently specs as that jumper:

<img src = "http://i.imgur.com/OMR3iFZ.jpg">

Bob · Mar 12, 2016

Cable from RH battery (+) should go to stud on starter "belly" towards engine block.

Cable from LH battery (-) should go to large upper terminal stud on starter solenoid.

Obviously, voltage between the two will be 24 Volts (nominal).

4020 electrician · Mar 12, 2016

Are you sure it's 24v?

Bob Bancroft · Mar 12, 2016

As Bob indicates below. Probably back when I rewired my 4020, the updated ground "wire" from JD was just a little pigtail with a fuse holder in it, with a 20A slow-blow fuse. It can be placed at either end of the cable running between the batteries. For convenience I put mine on the right side. It has blown a time or two.

Also part of the update was a bracket with two circuit breakers, mounted at the starter, one for each side of the system.-(12V+ grnd, and 12V- grnd.)

David G · Mar 12, 2016

The wire BETWEEN the batteries should be large, the wire from that connection to ground is probably 12 gauge.

John T · Mar 13, 2016

GOOD ADVICE AND PICTURES ABOVE

If its a 4020 Diesel and you're using two 12 volt batteries, they connect in series and at the center tie point that connection is what has a jumper wire to frame ground so you have two 12 volt A & B feeds up to the light switch, one + ground the other - ground to operate 12 volt lights. Of course, the series 24 volts goes to the 24 volt starter.

John T

Tx Jim · Mar 13, 2016

Here's the fuse holder that came in the wiring kit from JD.

55 50 Ron · Mar 13, 2016

When all is wired and operating correctly, the starter current does not go through that smaller wire.

cornerpost · Mar 16, 2016

Spend a little more and convert to 12 volt starter. Just my opinion.

tim s · Mar 16, 2016

I second the motion...

Tx Jim · Mar 17, 2016

(quoted from post at 18:07:53 03/16/16) I second the motion...

I''l 3rd the "change to 12 volt motion".

Sberry · Mar 22, 2016

Best hing we ever did was put a Nippon DCenso starter and GM 1 wire alt on them. Threw all the factory wire in the scrap and put mechanical Murphy gages on and used 2 hi p[ower car batteries.

4020 batteries 12/24v

John Achmann

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David G

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John Achmann

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Bob

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4020 electrician

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