Electric conversion of a Kubota B26 / Similar

[Bob Rooks]

You’d have to totally strip the tractor transmission and put the electric motors to the wheels to gain anything.

Disagree. One DC electric motor is all that is needed (single power source and speed regulated just like the engine), regardless of how you power it - batteries or generator.

A diesel electric to drive a HST trans is not only pointless it’s a step down in efficiency.

Well, I can't disagree there but I think that was the OP's intent - electric motor to HST. Although there may be room in the differential housing for a pair of nice traction motors.

You’re still burning diesel and you’re still making noise. The only thing you’ve accomplished is wasting a bunch of money, cobbled up your tractor, and made it less reliable than it was to start with.

I worked in R&D for several years. Wasting money on things that worked on paper and cobbling them up to make them work was what we did best.

 

[4570Man]

Disagree. One DC electric motor is all that is needed (single power source and speed regulated just like the engine), regardless of how you power it - batteries or generator.

Well, I can't disagree there but I think that was the OP's intent - electric motor to HST. Although there may be room in the differential housing for a pair of nice traction motors.

I worked in R&D for several years. Wasting money on things that worked on paper and cobbling them up to make them work was what we did best.

Sure you could bolt an electric motor to the bell housing and drive the trans the same way or originally was and then strap on a diesel generator. But why? You’ve failed at making it quite, you’ve failed at avoiding having to smell or handle diesel, you’ve failed at making a better drive system like a locomotive. You’ve failed at making it more efficient. You’ve failed at pumping your ego about saving the environment. Just taking the diesel powering the generator and bolting it in the tractor would be 100x better.

 

[Bob Rooks]

Sure you could bolt an electric motor to the bell housing and drive the trans the same way or originally was and then strap on a diesel generator. But why? You’ve failed at making it quite, you’ve failed at avoiding having to smell or handle diesel, you’ve failed at making a better drive system like a locomotive. You’ve failed at making it more efficient. You’ve failed at pumping your ego about saving the environment. Just taking the diesel powering the generator and bolting it in the tractor would be 100x better.

I believe you missed my point entirely. This is R&D, remember? And btw, I failed at nothing. Apparently you have never dealt with concepts before. I digress.

 

[4570Man]

I believe you missed my point entirely. This is R&D, remember? And btw, I failed at nothing. Apparently you have never dealt with concepts before. I digress.

Usually a r&d project should improve them. What has been improved with this?

 

[Bob Rooks]

Usually a r&d project should improve them. What has been improved with this?

That statement proves you have no concept of R&D.
See if you can wrap your head around this:

SAGE Journals: Your gateway to world-class research journals

Subscription and open access journals from SAGE Publishing, the world's leading independent academic publisher.

journals.sagepub.com

 

[galstaf]

Wow... go away for a weekend and just watch the conversation wander around!

So
1> The whole point was to get rid of the diesel motor not replace it with another diesel ICE generator that would cost more than just replacing the dead motor. I want a machine that makes minimal noise and it dead quiet when it is not actively working.
2> I do have a bunch of batteries that I got at a killer price, so that is less of an issue. There is indeed about 30+ kWhs of capacity.
3> As many have pointed out, I am thinking that HST drive is unnecessary and wasteful if you have electromotive power, so it seems like a B26 is not the best tractor to try something like this with. So I am going to keep an eye out for a similarly distressed machine that is less cost and can be direct driven
4> Auxiliary power while the machine is working stationary is not a bad idea. I am not sure I would ever keep still enough for a corded solution to work, but a small quiet generator to top up on a longer working day may be an option. That and hot swapping some of the battery pack as it runs low.
As the tractor is not used every day or even every week, a solar panel on the ROPS could top off the batteries even if it takes a week to do so.

Keep the suggestions coming in! I love it! However please bear in mind the original post requirements.
My ideal machine would be all electric most of the time without involving an ICE. The machine would sometimes have to work indoors and you definitely get less sleepy and dizzy if you don't have a carbon dioxide creator belching out fumes right next to you. ;-)

 

[shooterdon]

Not a total solution, but for indoor operation a propane engine might be sufficient if you have some degree of ventilation. We used propane lift trucks extensively in our warehouses. Plus with propane, switching out the tank gets you up and rerunning quickly.

You did not list the tasks (or I missed that part), but what are you doing with the tractor indoors? There may be other ways to get your jobs done.

BTW, we used electric fork lifts at another site and they worked well, but could not be taken to warehouses without charging or spare battery facilities.

Anyway, I am not envisioning why someone would want to run a tractor indoors for very long. Lifting a moving stuff can be done with fork lifts.

 

[dodge man]

I personally hope your idea works. People that make this stuff work usually have good fabrication skills and are willing to have failures before they have success. I don’t have those skills.One thing is you have battery packs. Do you have the knowledge to calculate if they have enough juice to power the tractor? Construction equipment runs 8 hours a day or more, most homeowner stuff doesn’t. 2 hours of solid use might be enough for you most of the time.

 

[Bob Rooks]

BTW, we used electric fork lifts at another site and they worked well, but could not be taken to warehouses without charging or spare battery facilities.

Voila!
An electric forklift or stacker with side shift will have everything you'll need to make the conversion to all electric operation - traction motor (gut the HST and install motor) and electro/hydraulic controls. The only real challenge I see is battery compatibility. This is a concept only.

Example:

Hyster E40XL Electric Forklift

4,000 lbs. Max. Weight Capacity, 3 Stage Mast, 187” Max Lift Height, 82” Lowered Mast Height, 39” Forks, Side Shift, Open Operator Station, 36 Volt System

www.ironplanet.com

 

[Grumpycat]

Ok, then just diesel-electric. Simple concept using DC motor and generator. Speed and power are directly related to engine RPM up to governed speed.

Diesel-electric "hybrid" locomotive controls the alternator field to regulate truck drive and speed, not engine RPM.

 

[Grumpycat]

Usually a r&d project should improve them. What has been improved with this?

If R&D always results in an improvement then there is no point in the R&D step, just go straight into production.

R&D is beneficial even when all that is learned is how not to do something.

R&D is not beneficial when all one has done is spend somebody's money.

Engineer's motto: "Quick. Cheap. Good. Pick 2."

"Perfection is the enemy of Good Enough." We do a lot of things which are not perfect but good enough to get the job done which would otherwise never get done at all.

 

[/pine]

Personally I don't see much more than BX sized machines being offered as electric compact tractors in the future...they just do (or are meant to do) so much work for the battery they could carry...

But one aspect that I do like about the concept is being able to use regen braking...it still comes down to where the rubber meets whatever...but it would add a whole new aspect to working on grades...

 

[Bob Rooks]

Diesel-electric "hybrid" locomotive controls the alternator field to regulate truck drive and speed, not engine RPM.

That is true on the newer AC polyphase induction motors. I should have been more specific as I was alluding to DC to DC for simplicity. My bad.

 

[galstaf]

Voila!
An electric forklift or stacker with side shift will have everything you'll need to make the conversion to all electric operation - traction motor (gut the HST and install motor) and electro/hydraulic controls. The only real challenge I see is battery compatibility. This is a concept only.

Example:

Hyster E40XL Electric Forklift

4,000 lbs. Max. Weight Capacity, 3 Stage Mast, 187” Max Lift Height, 82” Lowered Mast Height, 39” Forks, Side Shift, Open Operator Station, 36 Volt System

www.ironplanet.com

An electric forklift was definitely on consideration list already for harvesting parts... a good sized the motor controller, motor and electric hydraulic pump.
I think I am gonna pass on the Kubota HST tho and wait for a more suitable non-HST machine.
I will update the thread as and when I make progress. Thanks for the input everyone.

If anyone else takes on an electric conversion also, please continue the thread!

 

[galstaf]

Personally I don't see much more than BX sized machines being offered as electric compact tractors in the future...they just do (or are meant to do) so much work for the battery they could carry...

But one aspect that I do like about the concept is being able to use regen braking...it still comes down to where the rubber meets whatever...but it would add a whole new aspect to working on grades...

I don't think it would add much. Regen really only works well with fast moving wheels (lots of rotational energy) with good traction. Too much regen/electric braking will just cause muddy tractor wheels to slide.

 

[galstaf]

Not a total solution, but for indoor operation a propane engine might be sufficient if you have some degree of ventilation. We used propane lift trucks extensively in our warehouses. Plus with propane, switching out the tank gets you up and rerunning quickly.

You did not list the tasks (or I missed that part), but what are you doing with the tractor indoors? There may be other ways to get your jobs done.

BTW, we used electric fork lifts at another site and they worked well, but could not be taken to warehouses without charging or spare battery facilities.

Anyway, I am not envisioning why someone would want to run a tractor indoors for very long. Lifting a moving stuff can be done with fork lifts.

You forgot quiet. I want a virtually silent machine also. An indoor machine is nice for digging out footings or pipe channels in an existing space.

Also I think most duel fuel propane motors need to be gasoline, not diesel.

 

[/pine]

I don't think it would add much. Regen really only works well with fast moving wheels (lots of rotational energy) with good traction. Too much regen/electric braking will just cause muddy tractor wheels to slide.

That's not the way our golf cart reacts...the regen braking is great for descending hills....2 WD....

Can only speak about the cart but it never loses traction when regen braking...but hit the foot brake in mud and you can go sledding...

 

[jonsstihl]

I would definitely start with a donor tractor that is not HST and if possible closed center hydraulic system but those are rare on compact tractors.

 

[Bob Rooks]

Also I think most duel fuel propane motors need to be gasoline, not diesel.

Nope. Just add spark plugs, magneto, and a carburetor (simplifying). Caterpillar used to do it.

 

[CalG]

Nope. Just add spark plugs, magneto, and a carburetor (simplifying). Caterpillar used to do it.

View attachment 710068

Compression ratio might be a tad high. "just slide another headgasket in there, and call it good" ;-)

To the OP

I've got an motor out of an electric warehouse stacker. I think its 36 v might be 48v

Yours if you want it, but it's some distance away and VERY HEAVY. ;-)

I take that back, I'll trade for ONE of the bike battery pacs. I could use a second one for my e-bike ;-)