Switching My 2009 B3200 from low amp Dynamo to Kubota 40 amp alternator

[motorhead]

FINISHED switching My 2009 B3200 from low amp Dynamo to Kubota 40 amp alternator

My 2009 Kubota B3200 came with the little 10-15 amp dynamo and external regulator. I always try to run the tractor long enough and at medium engine RPM to get the engine hot enough to keep moisture out of the oil and to keep the battery charged. A few times when I was running slow engine speeds with my 4 way flashers on and headlights on, I ran into a low battery upon restart.

I researched the Kubota USA parts microfiche and in the front after picking what tractor I had, I looked up the "OPTIONS" page. There I found that the 40 amp alternator was an option kit for the B3200. The "Kit" is no longer available but the page that showed the kit gave the part numbers of the parts needed to convert. You have to change to the different engine oil dip stick because the one for the Dynamo won't clear the alternator.

The wiring loom is no longer available but that is not an issue for me as I have many years of automotive and equipment wiring experience. I will make up my own wire loom and use the dash dynamo light as the alternator light when the ignition is turned on. I may have to isolate the alternator light wiring at the instrument cluster from the rest of the indicator lights but I will see when I get to that. I will also use a 12 volt CUBE LOAD Relay to keep the extra 2.5 amps the alternator takes to energize it off of the ignition switch. The nice part is that the Kubota, Nippon Denso alternator is INTERNALLY REGULATED, meaning that the voltage regulator is built in on the back of the alternator.

I found the New Old Stock Kubota/ND alternator on ebay for $85 plus shipping. Another seller had the same alternator but wanted $235 dollars! pays to search. You can buy the cheapo Chinese knock offs but I got lucky and found the OE part. I also had to find the "T" shaped plug for the back of the alternator. I found it on ebay for about $8 bucks. Only issue is that the female push on connectors are very thin. I bought some thick gauge ones from an electrical supplier so I will just use the plastic plug and make up my own wires when I make up the Alternator wiring loom.

I WILL post my work on the conversion with pictures. The picture show the parts I got from my local Kubota dealer and the part numbers. The parts were just under $100 shipped to me and I am into the alternator for about $100.

 

[motorhead]

I finished today the alternator conversion. I needed and used all of the parts I listed and they all fit properly. The oil dip stick will be a little harder to get to but the benefits of the alternator were seen right away!
I removed the dynamo, old belt and upper adjuster bracket. Installed the new parts and then the new Alternator and adjusted the belt tension. I ran a #8 battery wire from the Alternator directly to the starter where the positive battery cable hooks up. I took the "T" plug and made up a wire loom consisting of a #14 red for the ignition wire to the alternator and a #16 blue wire for the alternator indicator light.
I pulled the instrument cluster out and the lower kick panel. Up at the speedometer cluster, I removed the battery charge bulb socket. My cluster has a blue with black stripe wire and a solid white for the charge indicator light.
The DYNAMO uses a different type of electrical circuit than the alternator does. I carefully cut the white wire leaving about 2" on the socket and the same on the instrument cluster loom. I ran a #16 wire, could use smaller but I have #16 on hand, to the plug where the cluster ties into the main loom via a gang plug. I found a "Key ON" wire which is a green with white stripe on the CLUSTER side of the plug and a red with yellow stripe on the main loom side. On the cluster side, I tied into the green/white stripe wire and added two extra wires, a white and a green. I SOLDER ALL of my connections, even the crimp connectors where possible. The white wire went to the white wire on the charge light, the green wire went to a load relay closing coil I added into the system, explained later. The Blue wire on the charge light, I removed it from the gang plug and added enough solid blue wire to go to the "T" plug on the alternator which triggers the charge light. So now when you turn the key on, ignition voltage goes through the white wire on the charge light and because the alternator is not producing electricity, the blue wire grounds through the alternator. Once it turns and is charging, it cancels the dash charge light.
The alternator FIELD draws about 2.5 amps. I did not want to run the extra current through the key switch so I added a "Bosch cube style" SEALED load relay.
So the green wire I added from the ignition went to one side of the relay coil, #85, and the other side, #86, I grounded. I tied into the plug that used to connect to the DYNAMO regulator and found a constant on BATTERY positive terminal. That went to the #30 on the load relay which is where you hook the supply power you want to switch. I added a #14 red wire to the #87 terminal on the load relay and it goes to the "IGN" terminal in the "T" plug which plugs into the back of the alternator. #87 terminal on the cube relay is the Normally OPEN terminal that when the relay is energized on the closing coil now has voltage. So when I turn the tractor off, the alternator disconnects. I mounted the relay on the flat bar that the control box and the run relay is mounted. I had to drill a 6.5mm hole just above the two factory relays.
After I unplugged the voltage regulator, I tried the starter and NO-GO. The dynamo regulator has a key switched terminal also and it apparently works in conjunction with the tractors CONTROL box. You will see a jumper on the regulator plug. It jumps from the red/yellow ignition to the white/red which now energizes the control box. WA-LA...I now have a starter and the tractor starts. I double checked everything, got my DC clamp meter on the battery cable and started the tractor. At IDLE, I was reading 6.85 amps. I brought the rpm up to about 1500 rpm and and read 15 amps. I have a battery load meter to load check batteries. I hooked it up to the battery with the tractor running, pushed the load button on the checker and read 12.5 amps going to the battery. This is about double what the little Dynamo would put out.
I sheathed and tie wrapped the looms I made up and put the tractor back together. I readjusted the V belt as it loosened some because it is new.
My charge voltage is now at 14.5 volts running.This was well worth the money and time for my usage of my B3200.

 

[motorhead]

Last pictures of the install.

 

[JerryMT]

You do nice work! looks good.

 

[albertcaballero]

Re: FINISHED switching My 2009 B3200 from low amp Dynamo to Kubota 40 amp alternator

Great job. Thanks for the info

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[Kubota BX 1860]

Re: FINISHED switching My 2009 B3200 from low amp Dynamo to Kubota 40 amp alternator

Very nice work. The dipstick doesn't look too bad at all. Congrats!

 

[motorhead]

Thanks to those who posted replies. To those who replied, does your tractors have an alternator or the dynamo? I'm 65 yrs old and have worked on cars, motorcycles and equipment for 50 years. I don't understand why some of the smaller Kubota models came with alternators and the largest "B" series, at the time the B3200 with a 1.5 ltr engine, came with the small low amp dynamo.

I used the tractor yesterday and started and stopped the engine several times and it sure starts faster now.

 

[albertcaballero]

Re: FINISHED switching My 2009 B3200 from low amp Dynamo to Kubota 40 amp alternator

I have the small version. I will upgrade when this one goes out.

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[JeepinMaxx]

Nice clean conversion!

 

[motorhead]

Re: FINISHED switching My 2009 B3200 from low amp Dynamo to Kubota 40 amp alternator

I have the small version. I will upgrade when this one goes out.

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For the costs of at least the parts from Kubota, less the alternator, I would buy the installation parts when you can as you never know when they will become unavailable.

 

[albertcaballero]

Re: FINISHED switching My 2009 B3200 from low amp Dynamo to Kubota 40 amp alternator

So $100 in kubota parts, how long did the installation take?

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[motorhead]

Re: FINISHED switching My 2009 B3200 from low amp Dynamo to Kubota 40 amp alternator

So $100 in kubota parts, how long did the installation take?

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I had to do some investigation to figure out the electrical wiring so that took some time on the install. Removing the dynamo and installing the alternator without the wiring took less than an hour. It took me probably 7 hours with investigation of the wiring. I believe now that I would not have had to splice the wire loom at the instrument cluster as with the jumper I put at the dynamo voltage regulator plug, as seen in my picture, would have energized the Battery charge light on the one side. The blue wire from the other side of the charge light would remain as I have it, removed from the gang plug and run to the charge light port on the alternator. I also would have energized the one side of the latch coil for the cube relay at the same jumper.
To do it again, I would figure 4 hours total and that is to do a NICE job.

 

[MILESKellogs]

Re: FINISHED switching My 2009 B3200 from low amp Dynamo to Kubota 40 amp alternator



I had to do some investigation to figure out the electrical wiring so that took some time on the install. Removing the dynamo and installing the alternator without the wiring took less than an hour. It took me probably 7 hours with investigation of the wiring. I believe now that I would not have had to splice the wire loom at the instrument cluster as with the jumper I put at the dynamo voltage regulator plug, as seen in my picture, would have energized the Battery charge light on the one side. The blue wire from the other side of the charge light would remain as I have it, removed from the gang plug and run to the charge light port on the alternator. I also would have energized the one side of the latch coil for the cube relay at the same jumper.
To do it again, I would figure 4 hours total and that is to do a NICE job.

thanks for taking the time to post this

 

[lugbolt]

they used dynamo's because they worked, and were cheap to make. Also cheap to repair when that time comes. There's nothing to them. Two bearings and a nut, and a weird shaped bolt--and a little stator. I've got 30 years dealing with them and in those 30 years not one has ever had an electrical problem, a few bearings seized but that is all. Unless the machine is used for frequent starts/stops, and/or has added electrical accessories that overpower the dynamo, there is no real reason to put an alternator in it's place. In other words, I live on the kiss principle. Keep it simple, stupid. If it's not needed, don't put it there, and if'n it ain't broke, don't fix. Kubota put dynamo's on for a reason and it wasn't because the alternator works better, it was because it satified the need for recharging the battery at minimal build cost, with acceptable performance and good (excellent, IMO) reliability.