Electric tractor project

[woodsmith]

I am working on an Electric Toyota MR2 project but to learn more about how EV's work I started a second little project.
I've nowhere to drive it and no land to need to use it on but it will be both fun and good for shows.

So in some sort of chronological order of making the (very) brief tale starts here:

I was gifted one of these.

Made one of these to match.

Added one of these.

Mock up.

Remade one of these.

Got these gifted from an EV friend in the States.

Turned these...

Into these.

Made one of these

To fit like this.

And like this.

To give this.

Then found these.

And made these.

And these.

And we have this.

Then it grew some bigger rubber!:thumbsup:

Had to do this.

So that this could happen.


And this.


A quick chassis upgrade.

Made these.

To get this.

And then made this.

Got one of these.

And was gifted four of these.

Made some more of this.

Pulls little wheelies with 12v!


Proper test.


It moves so it needs these.

Made this.

For here.

Then this bit.

Because straight roads are boring.

As are flat ones.

Looks a little like this now.

But Optimas live like this.

How about a big 12" motor?:laughing: Nah, that can go in my MR2 EV.

Just added a seat mounting.

Underseat controller=budget seat heating!

This whole project has been made from gifts, dirt cheap Ebay finds and raiding the scrap metal yard on the way to work.

There is a full write up here. Woody's Tractor Project - DIY Electric Car Forums

I've not driven it yet, no seat (the plastic one is temporary) or controls fitted. And it is on a basement workshop so no space to go anywhere until it is rebuilt outside. Then I will try and get someone to video it.

I am planning on using a fiddle brake system on it. Right foot throttle and service brakes, left foot steering brakes. I have to get the seat sorted before I can work out the ergonomics of the controls. I might continue to use the slider pot (in the vid) for a throttle as it works and is there.

The plan is to make it work and clothe it in a wooden body and seat to show off my cabinet making skills.

 

[rmully]

Looks like a really fun project...keep us posted on your progress.

 

[woodsmith]

Thanks, I will do that.

I spent a lot of time lurking on here reading the threads on conversions and DIY stuff as I was building but thought it was high time I registered.

I am currently concentrating on my MR2 as, due to a favour from an engineering technician at a college, he produced a motor coupler that wasn't centred or true.:confused2:

I am having to remake everything again but I am going to do it myself.

 

[Johndeere3720]

Looks like a really fun project. Are you going to make a hood for it? when you rebuild it outside, what will you use it for?

 

[woodsmith]

Looks like a really fun project. Are you going to make a hood for it? when you rebuild it outside, what will you use it for?

I am going to make all the bodywork from wood to show of my cabinet making skills. I have some American cherry left over from a previous project and also a pile of English cherry logs.

The plan is to make a cherry wood hood and front grille something along the lines of the Napier Railton.

I am looking for a set of lights to fit in the front cowl to start off the shape, probably a set of airdam foglights, the projector lamp type. The rear wheel arches will have rectangular spot lights to the front and round red and white lights to the rear from a Land Rover Defender.

I haven't thought as far as what I would use it for as my rear garden is the size of a postage stamp and my front drive way is only 50' long!:confused2:

I do live on a private road and get on well with my neighbours. I cut a 40' tree down for one a little while ago and still need to fetch back the logs. It should be good for that.
I also do a lot of building work for various neigbours and the tractor with a small trailer would save using the car or walking back and forth with heavy tools and materials.
It can also drag my big trailer around collecting building rubble before I hitch up the car to take it to the tip.

 

[woodsmith]

Well it has been a while and I have been busy on other projects but recently got back on to the important one of the tractor.:thumbsup:

I relocated the controller and started making the wiring loom for the high voltage control circuits. I have put in a temporary dash board to sort out locations and cables and to start real testing for the control circuits, throttle and battery monitoring.

Here is video tour of the work so far.


Of course I couldn't resist having a ride, even though the tractor is in a small basement workshop. So I shot a video for my friend, Jim, who inspired me with his electric pulling tractor.


I was being really careful with the throttle pot in my hand. It is more then capable of chirping those big 34" tyres and climbing an 8" vertical step in front of both tyres from a stand still. I have already broken the leg off the table behind it by inadvertantly pushing into it when I forgot to switch to forward from reverse.

 

[mjncad]

Now that's cool, a Morgan inspired wood bodied electric tractor. How about adding some Meccano and Legos to boot. I saw James May's 'Toy Stories' building a full size house and a bridge in Liverpool from these toys.

Looking forward to more pictures and videos.

 

[jayste]

Great project! I'm looking forward to more. :thumbsup: Totally from scratch and scrap....I like it!

 

[woodsmith]

Cheers guys, this project is a lot of fun to do.

Today I got the parking brake sorted out by using a bit of lateral thinking. I was trying to get a V belt to work on the pulley but I decided to have a lock bolt on the holes in the pulley centre instead.

I used a bit of springy flat bar with a bolt in it that locates on the holes and then fixed the bar to one of the transmission bolts. I then made a push pull shaft with a ramp on it to engage/disengage the bolt. A simple lever will move the shaft back and forth without the need for a ratchet or any other complex mechanisms.

Brake on:

Brake off:

I also started sorting out a gear lever linkage to connect to the gear knob that was under the seat.
I made use of a couple of holes on the side of the transmission case to mount a bracket and then made a crank to work the selector.

the fork is a loose fit on the selector but trapped between the washers and the nut. The other end will have a push pull shaft to a lever.

I've not made the levers for either the parking brake or the gear shift as I am thinking of making them from wood. also I need to have the seat position finalised before I can be sure that the levers will be accessible and not in the way.

 

[czechsonofagun]

Riveting picture story, great job. Keep them coming

 

[woodsmith]

I made a parking brake lever.

Brake off:

Brake on:

It works well enough to stop the tractor from rolling away but while playing I forgot to let off the brake before applying drive. The brake broke. The bolt in the pulley spokes was ripped out and the steel strap twisted all out of shape. I have now 'beefed' it up a lot but I might remake it in my usual 6mm steel. It will be fine for parking up though.

I also made the gear lever from some 20x2mm box tube.

The link is a bit of 5mm rod that I had spare. I formed eyes into the ends to fit the M8 bolts.

Trying it out I found that the curved part of the lever was rubbing the back of my knee while sitting so I adjusted it.
I shortened the rod and put a twist into the lever so it is further back.

The next thing was to make the brake pedal. That was more my usual over the top and over engineered part. :laughing:

I still need to make a bracket for the master cylinder and also I will need to bend the crank lever over a bit as the cyclinder is a little close to the edge of the pedal.

This is how it all looks from the driver's seat (excuse the view between my legs! :ashamed: ).

You can see how the brake pedal fits in
The gear lever, to the right, is forward for low gear. High gear is only a 1 1/2" backwards.

I also have this master cylinder.

It will sit low between the chassis rails and have a conventional hand brake lever over it. It will be plumbed in line with the foot brake working on the same hydraulic line so I won't leave it on when parked over night, the bolt in the pulley spokes will surfice for that.

I also tried the MR2 throttle pot.

It works but, like the slider pot, seems to have a dead area over the first 1/4 to 1/3 of the action. I am begining to wonder if it is controller programming.
Reading the manual I can see that I can reprogramme it with a £450 programmer or by manual methods with the flashing LED. However, it doesn't say how.

 

[woodsmith]

Things have moved on a bit.

I had to remake the brake pedal to get twin masters for fiddle brakes.

I also managed to get some gauges. A big old retro 0-50V voltmeter and a couple of clip on ammeters, +-100A and +-600Amp.

I also managed to find a throttle pedal with built in pot. It is from a Land Rover Defender TD5. Compact, cheap and easy to fit so Ideal.

I then stripped the tractor back down to it's components for painting. I have opted for satin black on red oxide. Unfortunately, now that the tractor has been taken outside piece at a time I can see where the red still shows through the black and there are definate 'holes' in the black paint so it will need repainting to cover those and the chips and scrapes from building it up again.

So now it is outside and I have the brakes on it.
The pipes are stainless braided flexibles in red sleeve made up for me by David at Llama 4x4.

The red goes with the red calipers.

So here she is.

I added my retro voltmeter to the temporary dash.

I will need to try and find a 350A ammeter to match.

I also put some 'carrots' on the controller terminals.

It now lives in my carpeted furniture moving trailer. Looks made to measure.

The only snag is that the brake pedal is too hard to press. I will need to change the effective lever ratio on the pedal. It has worked out at around 2:1 and I need to change it to somewhere nearer 5:1 or better at 8:1.
Then I need to get on with making the wooden seat and body shell for it incorporating all the lighting.

 

[Johndeere3720]

That looks so cool! :thumbsup: great job! :thumbsup:

 

[brokenot]

Reading the manual I can see that I can reprogramme it with a ｣450 programmer or by manual methods with the flashing LED. However, it doesn't say how.

That would be unusual.

Usually, the LEDs are just for quick diagnosing of fault conditions. Some Curtis controllers have trimpots hidden under screw covers for tiny adjustments of some functions like plug-braking, but controllers like the one you have *likely* need a hand-held calibrator for any programming adjustments. Alternatively, a laptop can be used in place of the hand-held programmer, but the software and interface cost more than the programmer itself does.

We've got two programmers at work for setting up MOS90 Sevcons like this, but they won't work on any other controllers:

Cool project by the way!

 

[Mace Canute]

I also managed to find a throttle pedal with built in pot. It is from a Land Rover Defender TD5. Compact, cheap and easy to fit so Ideal.

Just as long as it doesn't come out of a Toyota car!

 

[woodsmith]

Thanks for the support, it has been a great little project but now the hard work begins and I must build body work in my wood shop.

Brokenot, I think you are probably right and the controller only allows diagnostics and not programming. I may be confusing it with another 'black box' thing I worked on a while ago that allowed programming by counting the LED pulses and 'flashing' one of the switches at the appropriate time as it cycles around the parameters.

I don't know how reliable Defender throttle pedals are, they come up for sale every so often when owners change from the TD5 diesel to a V8 gas engine but I've not heard news reports of any runaways, yet.

 

[woodsmith]

Broken photo link in previous post.

To solve the brake problem I decided to combine shortening the lever at the cylinder end and then adding a second link as a multiplier.

You can see from the other side that the lever from the pedal pivot is now very short and that now works on an adjustable pull rod onto a 2:1 lever pivoted on a frame bolted above the master cylinders.

The return springs are a big snug but it shouldn't be too much of a problem.

I also decided to tackle the throttle pedal. A bit of loom and a plug arrived for it today. I tried it but nothing happened and the controller flashes throttle fault.

I removed the throttle and checked the readings again. After a few more trys and checks I discovered that my ｣1.99 multimeter that was Dad's left over stock wasn't reading right.
I had to set it to 20k and it quite happily read something low and flickery at one end and 5.6k at the other end. What I didn't realise was that it didn't read low ohms accurately unless I then switched it down to 200ohms and the 20ohms.
Testing with my quality DMM it told me that it was about 2k to 5.7k so no good.

I toyed with the idea of doing something else with the pedal and the MR2 throttle TPS but then decided that as the TD5 pot was scrap I might as well open it up and have a look inside.
It has 3 resistance tracks, three wiper tracks, three wipers and three resistances.
I found one track that was 5k, great. Unfortunately the only way it was connected to the pins was via a wiper track that had a 2k resistance in line.
I decided to 'hotwire' it and so I soldered a wire from the pin to the wiper.

I then checked it and found that the pedal at rest didn't allow the wiper to hit zero so I set about adding more range of movement both inside the pot and in the pedal.
I had to grind away a bit of the pedal so that it stopped higher when the pot read zero.

Great stuff. I now have a 5k throttle pot that goes from zero!
I put it back on the tractor and...

...Still no go.
Long story short, with a lot of messing about and fine tuning I discovered that I had rebuilt the pot to work from 0-5k and the controller wants 5k-0.

So I had another play with the insides of the pot and manage to get a set of connections that allows me to have 5k-0. Of course, now the pedal didn't have enough travel at the other end of the pot. It means that I now have 5k-0.7k so I can't get full throttle.

So the following morning, having finished working on it at midnight, I sorted out the throttle finally and fitted it.
It works great!

The snag now is that there is no activity from the controller for the first 20mm of pedal travel. So I reworked the pedal to remove the excess travel and measure the pot resistance. It was 4.7k so I have set the pedal to start from 4.75k.
I now have an almost instant throttle response.

The only thing left is to fit a hand brake lever and to make some ramps for the back of the trailer so I can get the tractor back out again! Then I can start on the body work.

 

[woodsmith]

Some good news and some bad news.

Good news:
I have video of me, and my Dad, driving the tractor about in first gear. second was a bit too fast and bouncy on the cobbles and there is no padding on the seat.

Me:


Dad:


Bad news:
While playing and falling about laughing with silly EV grins I managed to get a clunk from the transaxle. I think a tooth has broken off.
I will need to see if anything comes out with the oil and look for a stronger replacement one.

 

[woodsmith]

OK, its been a while, work, bad weather, more work...:confused2:

I finally got around to taking out the broken transaxle.:thumbsup:

Wheels off.

Transaxle out.

There was a distinct rattle inside the transaxle, something that says much bigger then just teeth.
I got it back onto the workshop and opened it up.

Now I'm sure I drained the oil when I put it away last year, I'm certain of it, (checks previous images) Yep, theres a bucket and a load of oil in it under the axle.

Anyway, there are some big bits in there.

The crown wheel is in six pieces, plus spider gears, broken teeth and other shrapnal.

I had gotten hold of one of an old Wheelhorse a while ago just in case.

I removed the transaxle from it.

When I drained the transaxle, and I did actually drain this one, I got two pints of water and a pint of mayo!

Still, I got it in the workshop and started to take stuff off it to open it up. It won't open yet as there is the hitch pin through the case that is rusted solid, I will deal with it later. It turns out to be a Unidrive 4 speed (3F-1R) with I think a LSD.:thumbsup: It will stop me having fiddle brakes though if it is a LSD.

I wanted to change to Land Rover rims to make it easier to get rims for different tyre use, road and agri, so I thought about using a couple of old Discovery hubs.
It turns out that the locating spigot on the Wheelhorse hub exactly fits in the oil seal rebate on the LR hub.

:thumbsup:

The five bolt holes don't quite match but I can slot the WH hub holes and then make a spacer so that the WH hub can bolt down to the LR hub and still secure the brake disc.

That will be another week's job though.

I will try to drill out and heat the stuck hitch pin so that I can remove it and open the box. Can't risk not checking it is ok on the inside with all that water.

 

[94BULLITT]

That's a cool project. Do you plan on using it to do any work?