Kubota B7100 wiring problems

[BP176]

Hi Guys,
I have a 1982/3 B7100, which is not charging its battery, it also spins over very slowly on start up. My local shop has rewound the starter motor, and reconditioned the alternator. It’s had the new updated electronic regulator installed.

It’s still not charging, has anyone got a wiring diagram for it, the one I have shows 2 wires coming from the alternator, but actually this one has 5. 3 are grouped together on one plastic connection and there are another 2 on a bolt.
There are 6 wires on the connector to the regulator, the diagram I have shows 4?

Any help much appreciated, many thanks.

 

[GreensvilleJay]

Who installed the new regulator ? They should have the wiring diagram.....
'reconditioned' the alternator ?
hmm, something that old probably had a 'dynamo'. Spinning magnets and 2 wires, producing +-30V AC.

Really need to post pictures of 'alternator' and 'regulator', and current wiring to make the 'long distance diagnosis' !

 

[BP176]

Who installed the new regulator ? They should have the wiring diagram.....
'reconditioned' the alternator ?
hmm, something that old probably had a 'dynamo'. Spinning magnets and 2 wires, producing +-30V AC.

Really need to post pictures of 'alternator' and 'regulator', and current wiring to make the 'long distance diagnosis' !

I installed the new regulator
4 bolts and a one way plastic connector seemed very easy.
I used a shop that specialises in alternators, they assured me it was a drop straight in replacement.

 

[jaxs]

What did those that tinkered with it say when you told them they hadn't fixed it? Hopefully they apologized and gave your money back. If everything was still original as shown in shop manual there's people here that could walk you through it.

 

[BP176]

The new electronic box

 

[BP176]

What did those that tinkered with it say when you told them they hadn't fixed it? Hopefully they apologized and gave your money back. If everything was still original as shown in shop manual there's people here that could walk you through it.

Erm
I haven’t spoken to anyone yet as the shop won’t be open till Monday
Just trying to get something sorted, it’s a work tool for me and I’m trying to minimise down time
Any help is much appreciated,
I should say I bought the tractor secondhand with 3600 hours last year so I may be dealing with inherited problems?

 

[Henro]

Kubotabooks.com has the workshop manual available for free download. Electrical diagrams start on P307….

Look here: https://www.kubotabooks.com/AutoIndex/index.php?dir=Tractor Owners Manuals/

 

[GreensvilleJay]

so that alternator you show in the 1st 2 pictures is the old one ??
can't read the make/model of the regulator....

also you really,really need to CLEAN that tractor..... dirt and electrons don't play well together

and did you install a new belt ?

 

[PoTreeBoy]

Kubotabooks.com has the workshop manual available for free download. Electrical diagrams start on P307….

Look here: https://www.kubotabooks.com/AutoIndex/index.php?dir=Tractor Owners Manuals/

His tractor originally came with a dynamo. Somebody retrofitted it with an alternator, so the diagram doesn't help him. Kubota has offered an aftermarket kit for some models. I think Jay's trying to figure out what he's got.

 

[BP176]

The alternator is the first and second pics is the original one before being removed. The same alternator is now on there after being reconditioned.
I did not install a new belt as that looked a in depth job and the belt seemed in reasonable condition.
I attach photos of the alternator post reconditioning in its current position and better pics of the electrical box
I’m assuming that the alternator is a factory original?
Many thanks

 

[ken erickson]

Kubota did offer an upgraded higher output dynamo (alternator) for the B7100 with very detailed instructions for mounting and wiring. You may be able to glean some useful information from it.

 

[Jim L.]

Bit of a recap on what is needed: Alternator brand and model number. Regulator brand and model number.

Original was a 2-wire AC dynamo. 2 green wires.

Original regulator essentially an AC to DC converter. Took 2 green wires from dynamo with AC. 1 wire, black, to ground. 1 DC output, red.

With the new part numbers, need to check if new alternator and new regulator are matched for amperage. And knowing manufacturer and part numbers can see what manufacturer recommends for wiring on old-style circuit or new combination.

 

[Henro]

His tractor originally came with a dynamo. Somebody retrofitted it with an alternator, so the diagram doesn't help him. Kubota has offered an aftermarket kit for some models. I think Jay's trying to figure out what he's got.

Maybe so, maybe not. The new stuff is connected to the old stuff.

Regardless, it appears the OP does not have the workshop manual since if he did, he wouldn't be asking about an electrical diagram.

Having access to the workshop manual may be of some use to him in the future if not now…

 

[BP176]

So
When I bought the tractor the alternator was a
Nippondenso 12v 15253-64011 02-00V-86
And the regulator was
Nippondenso 02600-21-21 12v 2B

Currently after the work that has been carried out the alternator is a
Nippondenso 12v 15253-64011 02-00V-86
And the regulator is
HC Cargo 130627 14v F.032.130.627.ZEY

It does seem that the large capacity Alternator as described above is the system that has been fitted.

Is there any common faults that affect this charging the system?
Much appreciated

 

[Henro]

So
When I bought the tractor the alternator was a
Nippondenso 12v 15253-64011 02-00V-86
And the regulator was
Nippondenso 02600-21-21 12v 2B

Currently after the work that has been carried out the alternator is a
Nippondenso 12v 15253-64011 02-00V-86
And the regulator is
HC Cargo 130627 14v F.032.130.627.ZEY

It does seem that the large capacity Alternator as described above is the system that has been fitted.

Is there any common faults that affect this charging the system?
Much appreciated

If you already mentioned the battery as far as whether it is old or new, I apologize cause I don't remember.

If not, I would ask are you sure the battery is good? How old is it?

Perhaps your issue is the battery and not the work that was done. Just something to think about. Probably doesn't apply if the battery is new, but if it's 10 years old, that could be a different story…

 

[BP176]

If you already mentioned the battery as far as whether it is old or new, I apologize cause I don't remember.

If not, I would ask are you sure the battery is good? How old is it?

Perhaps your issue is the battery and not the work that was done. Just something to think about. Probably doesn't apply if the battery is new, but if it's 10 years old, that could be a different story…

I have tried 2 batteries on it, the one I came with dated 2019 and an unknown one.
I am currently jump starting it with my Series 3 Landrover battery.
When the tractor is running I am measuring 10.5v across the battery terminals.
I’d have thought this should be much higher with the alternator charging the system?

 

[Jim L.]

When the tractor is running I am measuring 10.5v across the battery terminals.

Not charging. With the posted pictures we get a better idea of what is there.

On the back of the alternator, there is a connector. What markings are on the alternator identifying the pins on that connector? Example: IG, E, F...

Besides the already mentioned drive belt, are all fuses working?

 

[jaxs]

You are right in expecting more than 10.5 V across battery terminals while tractor is running,,,,,BUT,,,,,,,,if the battery is defective alternator doesn't receive correct signal to trigger alternator output. Take time to put battery on charge and see if it comes up to minimum of 12.5 V preferably 12.7V across terminals. Just to cover all the bases ,once battery is at full charge it is wise to have it load tested free at most any parts store.

 

[BP176]

Much appreciated.

i have spent time today investigating what I can.
After studying the wiring diagram for the large capacity alternator, I found that there should have been a “charge light”. I actually found this on the tractor, but this has never worked since I bought the tractor.
I changed the bulb but to no avail. The connection before the bulb holder is showing 10.5v. So I’m beginning to suspect the bulb holder may be faulty?
would this cause a issue?

The alternator has ”B” at 12 o clock on the plastic connector and “E” at 9 o clock.

Ive been checking wires for continuity too, have I missed anything?
Will get the battery professionally checked tomorrow.

Many Thanks

 

[Jim L.]

I would expect to begin the trace from the regulator connector. Its pins are shown on the device with respective designators. IG, N, F, E, L, B.

On the alternator, there is, or should be, a large bolt for +12 VDC. Also on the alternator, a plastic-body connector with several pins. Normally, one would expect N, F, and E to be marked, respectively.

IG turns on the regulator. I would expect that to go to the main switch.

The big red conductor from the alternator post goes to the battery and should go to a fuse block. Feeding off the power would be a fuse providing +12 vdc to the regulator pin B. (battery sensor)

Regulator L goes to one side of the battery (or charge) light. The other side of the light goes to +12 vdc power.

That's what I would expect to find, but your mileage may vary. My previous question about the fuse is to make sure that regulator pin B is getting reference.

Always disconnect the battery when messing with the alternator or regulator.