Tractors...

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pengyou   1 kW

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Tractors...

Post by pengyou » Mar 14 2015 4:48am

Background: I have not visited or posted here in a long time. Quite a number of years ago I had 2 accidents on ebikes - almost back to back - and neither of them were my fault in the slightest. I decided then to give up ebikes for the sake of a longer life, at least until I am back in the US. I will be returning to the US in a couple of years and am shopping for a piece of land now. The land is going to require using some kind of tractor to maintain it. I have looked at many compact utility tractors and sub's but have not found what I am interested in. What I would like to have is a big platform on wheels similar to this
robotic cart.jpg
robotic cart.jpg (5.07 KiB) Viewed 1925 times
The shape intrigues me because the kind of land that I am looking at is likely to not be very flat, and I don't want to have to deal with a tractor pulling a trailer over uneven ground. The goal is to combine both functions into one vehicle.

I would like it to be bigger, about 7' long and 5' wide, with a lightweight backhoe and front loader attached. Total height will be 2.5-3' - yes, it is low, but low because one of the main things it will be doing is moving things around, whether leaves, straw or water, so the center of gravity is important. The deck will serve as a platform to carry things, or to mount a water tank on or a dump bed. I want it to be remote controlled - add more fun to the work :) so electric drive sounds like it would be more agreeable. There are other requirements and thoughts but I want to stay focused on the propulsion on this forum. I have already found a shop that is willing to do the welding for the chassis for a reasonable price - it will be their work in slow times over the next six months or so. The body/chassis, motors, generator, wheels, etc (not including attachments like the front loader, backhoe, tiller) will weigh in around 4,000 pounds (rough estimate). I would like it to be capable of moving 10,000 pounds when fully equipped or fully loaded at a speed of 4-5 mph, with an empty speed of about 10 mph. Minimum speed should be a "continual crawl" - at this point I could better quantify that at about half a mile per hour while tilling a new field. Ideally - because of cost - if I have to use gear reduction I would like to use chain, and no more than 5x. I am thinking that each of the 4 wheels will have a motor that will go as fast forward as it does in reverse. I have considered using 6 wheels instead of 4. Wheels will be 18" tall - atv or tractor. That will give it about 9" of ground clearance.

I have been snooping around tractor forums up until now, as well as reading tech specs for tractors. It seems that a tractor that would be doing much heavier work than what I want only uses 20 hp to move it around, and diverts the rest of the power to operating attachments.

Questions: I would like to know what kind of electric motors would be most suitable for this purpose, what size of motor and what kind of gearing (if any) is likely to be needed to make it go as slow as I need without burning out the motors or blowing up the controller. I have already had people tell me that hydraulic motors might be more suitable. I am open to follow that source but wanted to bounce the idea off of you folks here.

major   10 kW

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Re: Tractors...

Post by major » Mar 14 2015 9:56am

Just a thought. The photo looked similar to a chopped version of this 6-wheeler. Maybe you'd want to consider start with something like that for a platform. http://www.diyelectriccar.com/forums/sh ... 45362.html

Hillhater   100 GW

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Re: Tractors...

Post by Hillhater » Mar 15 2015 5:44pm

...the kind of land that I am looking at is likely to not be very flat,
... weigh in around 4,000 pounds...
I would like it to be capable of moving 10,000 pounds when fully equipped or fully loaded at a speed of 4-5 mph, with an empty speed of about 10 mph.
... about half a mile per hour while tilling a new field. ...
... It seems that a tractor that would be doing much heavier work than what I want only uses 20 hp to move it around,
20 hp to move it around, but not whilst moving 10,000lbs, ( 5 tons ?).. let alone over "not very flat land" . !
5 tons is a big load for any off road vehicle and the power required will vary enormously depending on the terrain and surface.
If you are considering electric drive, it will be the same old issue of battery capacity, size , weight, and cost,....... that you need to think about to provide the power needed for that kind of work.
You are looking at something along the lines of a 5 ton site dumper...
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LegendLength   100 W

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Re: Tractors...

Post by LegendLength » Mar 15 2015 9:17pm

I know you were asking specifically about the motors, but in case you haven't come across them yet, there are some open source 'rover' control systems out there. Last time I looked they were fairly beta but might be worth looking into. For example http://rover.ardupilot.com/ . Hardware cost is quite low (less than a couple of hundred bucks including gps & radio system).

Hillhater   100 GW

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Re: Tractors...

Post by Hillhater » Mar 15 2015 10:03pm

LegendLength wrote:..... there are some open source 'rover' control systems out there. Last time I looked they were fairly beta but might be worth looking into. For example http://rover.ardupilot.com/ . ..
It would be interesting to see that dealing with a 5 ton load ! :shock:
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Grinhill   10 kW

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Re: Tractors...

Post by Grinhill » Mar 16 2015 12:32am

Looks like a very interesting project.

I'm assuming that you are going with a "skid-steer" arrangement like a Bobcat. Could you find a wrecked Bobcat as a starting point?

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LegendLength   100 W

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Re: Tractors...

Post by LegendLength » Mar 17 2015 10:23am

Hillhater wrote:
LegendLength wrote:..... there are some open source 'rover' control systems out there. Last time I looked they were fairly beta but might be worth looking into. For example http://rover.ardupilot.com/ . ..
It would be interesting to see that dealing with a 5 ton load ! :shock:
Yeah i forgot to mention please don't refer to my post after it goes wild and runs people down :)

pengyou   1 kW

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Re: Tractors...

Post by pengyou » Mar 18 2015 3:57am

Thanks for your ideas. The dual track "tractor" someone referred me to is a step towards what I am looking for. Skid steer....am thinking of using that kind of steering - with 4 motors to control, the left 2 go forward, the right two stopped or in reverse and the vehicle turns left. There are a lot of variables up in the air. My concern right now is what kind of electric motor would be suitable for this application, keeping in mind that each wheel has an independent drive. Need low rpm, very low torque that is reversible. It sounds like 3 phase to me....
Last edited by pengyou on Mar 18 2015 5:05am, edited 1 time in total.

pengyou   1 kW

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Re: Tractors...

Post by pengyou » Mar 18 2015 4:18am

Thanks for the links. This is a little closer to what I envision, though longer and wider, with a lower profile...and a backhoe on the back :D ...and, more realistically, dealing with a 2.5 ton load.
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Last edited by pengyou on Mar 18 2015 5:02am, edited 1 time in total.


pengyou   1 kW

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Re: Tractors...

Post by pengyou » Mar 18 2015 5:09am

Hillhater wrote:
LegendLength wrote:..... there are some open source 'rover' control systems out there. Last time I looked they were fairly beta but might be worth looking into. For example http://rover.ardupilot.com/ . ..
It would be interesting to see that dealing with a 5 ton load ! :shock:
But the control system could probably be used for any size vehicle.

pengyou   1 kW

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Re: Tractors...

Post by pengyou » Mar 18 2015 6:01am

major wrote:Just a thought. The photo looked similar to a chopped version of this 6-wheeler. Maybe you'd want to consider start with something like that for a platform. http://www.diyelectriccar.com/forums/sh ... 45362.html
Yes, but the frame does not support much more than the weight of the people that would ride in it :)

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marty   10 MW

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Re: Tractors...

Post by marty » Mar 25 2015 8:03am

https://www.deere.com/en_US/products/eq ... ctric.page?
>John Deere TE 4x2 Electric T Series Traditional Utility Vehicles JohnDeere.com<
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List Price: $11,379.00* USD
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The fingers   100 GW

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Re: Tractors...

Post by The fingers » Mar 25 2015 8:55am

Someone needs to organize a national competition event for an unlimited class Lipo-powered all electric tractor pull. :twisted:
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dnmun   100 GW

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Re: Tractors...

Post by dnmun » Mar 25 2015 10:55am

you should avoid continuing this line of reasoning until you acquire a property to live on in the US.

at that point you can go ask your next door neighbor or anyone local who has used and is familiar with farm equipment for advice.

you do not wanna use a battery powered traction device as a tractor. period.

if you move to the country, your neighbors will help straighten you out if you just go and ask them.

it is not normal for people in the city to even know who their neighbors are.

in the country you will find that people are not so antisocial and will offer good advice and directions from their own experience and not some kinda internet anonymous misdirection.

major   10 kW

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Re: Tractors...

Post by major » Mar 25 2015 12:41pm

I've had very good and gratifying experience with small electric tractors on my 2½ acres for the past 12 years. I would not in any way claim a battery tractor is ready for prime time on the 80 acre field which surrounds my meager spread. If the needed chores require less than an hour or two of actual run time, then battery power can play a role.

Many of my farmer neighbors are interested in alternate energy looking at solar, wind and geothermal. And I have seen interest from them in electric vehicles for the short duty chores.

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