Electric tractor motors

Desertprep

1 kW
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Oct 27, 2007
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352
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I have some property in the high plains desert. I would really benefit from having a motorized 4 wheel platform that would let me carry up to 4,000 pounds (500 gallons of water). It does not need to go more than 5 mph, and does not need to climb more than 20 degrees. Tires will be about 24" in diameter. It would be ideal to have 4 hub motors powering this (to eliminate drive trains), but I don't know if their is such a motor that will handle this much weight. I don't want to do gas or diesel because this will constantly be doing stop and start action, which is really inefficient for either a gas or diesel engine - move it one place, do some work for 20 minutes, then move to another place, do some work for 5 minutes, etc. Distance traveled in one day is probably <2 miles. I would be willing to consider hydraulic motors in the wheels with an electric motor to power the pump. I plan on using skid steering.

I am looking for options now for the right kind of electric motors to use for this purpose. Most of the motors I know about are used to power bikes and scooters, higher rpms than I would need.
 
You will not find a direct drive hub motor to give you sufficient torque at low speed to haul 2+ tons up a 20 deg slope.
Simplest solution if you really insist to avoid diesel , is to convert an existing small tractor to an electric motor through the existing drive train. ..its not uncommon.!
 
+1 on the tractor suggestion, you'd need reduction gearing and it would work out far more complicated to build a vehicle from scratch than modify an existing one. Skid steer would be a killer with a 2 ton load as well, you'd probably use more energy on a single 90 deg turn than in 2 miles of straight and level travelling.

And I want to see more tractor conversions! :) On paper it's a match made in heaven, heavy battery weight is a hindrance for personal transport applications but for tractors it's a bonus and electric adds a whole new area to their versatility (along with PTO's and hydraulic takeoffs) that will probably open the door to countless new implements and applications.

The torque curve is absolutely perfect too, miles ahead of internal combustion with countless gears and slick ways of changing between them. Most manufacturers are already going down that route but their offerings are usually damn great behemoths that would have barely fit in a field a century ago, let alone get through the gate! Big agri has already run the numbers and come up with a big fat plus and that's all manufacturers seem to be interested in, they don't seem one bit interested in the smaller (and usually ancient) tractors most farms have that clock up far more hours per year doing the day to day jobs.
 
Thanks, hadn't come across anything like either of those before. Didn't think the second really qualified but it's hiding a damn sturdy structure and running gear under its golf buggy exterior, add a 3 point linkage and heavily treaded tyres and it could work well as an agricultural workhorse.
 
More traditional looking orchard size hybrid tractor.
https://www.alibaba.com/product-detail/Greenhouse-Orchard-Wheel-Tractor-Electric-Articulated_1600279476358.html?spm=a2700.galleryofferlist.normal_offer.d_title.3ea6bb8fwrJIA4

Several mini loaders are coming up with a search for "articulated", which may be a good option for quick steering. 500 gallons, I would consider putting on a tank trailer.
 
speedmd said:
More traditional looking orchard size e tractor.
https://www.alibaba.com/product-detail/Greenhouse-Orchard-Wheel-Tractor-Electric-Articulated_1600279476358.html?spm=a2700.galleryofferlist.normal_offer.d_title.3ea6bb8fwrJIA4

Several mini loaders are coming up with a search for "articulated", which may be a good option for quick steering. 500 gallons, I would consider putting on a tank trailer.

Did you send the wrong link? That's clearly a "4 stork" diesel motor in that one... "electric" refers to the electric starter.
 
Wrong link. Too many open at same time. :oops: Ali suppliers are always showing one thing and selling something very different. Careful with them. Looks like it may have electric drive on the hydro side on some models. Nice looking orchard tractors if they are not just stock photos.

Wanted to show the articulated mini loader. https://www.alibaba.com/product-detail/Tractor-Hot-Sale-Small-Lift-Loader_1600251213575.html?spm=a2700.galleryofferlist.normal_offer.d_title.3ea6bb8fswMqgw&s=p

The rickshaw-small side by side and golf cart type axles are made in a bunch of sizes and with high reduction ratios by a bunch of folks. Something like these would pull a tanker or be adapted. https://www.alibaba.com/product-detail/Transmission-48V-60V-72V-5000W-Motor_62551036902.html?spm=a2700.galleryofferlist.normal_offer.d_title.3e5057b77JAPRn
 
The heavy load and slow wheel-speed call for a high reduction. Cylindrical motors such as the QS 138/70H would be easier to package and mount under the cargo bed, but it is "possible" to use a hubmotor for a chain-drive to an axle, though i do not recommend that.

I appreciate the simplicity of hubmotors, and they have their place.

I would look for a large 4WD quad ATV with a fried engine to acquire the parts for the undercarriage.

I would use one motor for the rear axles, and a second motor for the front axle. Best of luck with whatever you choose, and please post pics of the results.
 
It would probably need an awful lot more weight than quad running gear could handle, either towing or carrying about 2 tons. A smallish tractor would be the ideal imo but usually the engine block is part of the structure/chassis, shouldn't be too hard to fill in the gap but it would need to be a damn heavy structure. A site dumper could be a good alternative, usually the engine and gearbox are on simple mountings with a driveshaft for the transfer box, easy to adapt to and high reduction. They usually need to be fairly well loaded to have enough grip for towing (could be a good candidate for lead-acid), articulated steering kicks ass for reversing trailers!

EDIT: Hydraulic steering (and tip if kept), could be more work getting that working than the drivetrain :/ An electric forklift or truck tail lift pump/motor with a torque sensing switch on the steering column could be a cost effective option. Voltages might not work out well though, a qs138/70 would be plenty capable for the weight with the low speeds specified but 48v would limit it a lot and 24v would likely be far too low.
 
My Polaris electric ranger in 4wd low has no traction or power issues pulling around a 5 x 10 trailer fully loaded with hardwood up a 5% grade. Depending on the wood - moisture it's easily the weight we are talking about. I would not even attempt it in the economy power setting or out of 4wd. On board, anything much larger than 100- 120 gallons would not be a good fit for it's structure. The diesel compact tractor in low range does not even feel the full trailer. :) The loaded rear tires alone weigh close to the weight of the polaris with the wet batteries. Expect the ranger will not have its current traction once the battery gets swapped out to the Li pack which should shed some 750 - 800 pounds.
 
If the cargo is two tons (4,000 lb), then I suspect the loaded vehicle will have no problems with traction.

4K lbs is the weight of a full sized pickup truck with a V8. Thats heavy, certainly, but...

You are gearing it to 5 MPH with 24-inch tires. Full-sized commercial aircraft are maneuvered at the service hangar by a tractor that has a surprisingly small engine, because it has a low gear around 5-MPH.

I don't know what the cheapest ideal system is, but I would never consider a hubmotor for this.
 
spinningmagnets said:
I don't know what the cheapest ideal system is, but I would never consider a hubmotor for this.
Well how about 2 hub motors then ?..
[youtube]vI8lqWLDnWA[/youtube]
But this is a more conventional , low cost, electric conversion of a traditional tractor...
[youtube]yDgYeF2c9_I[/youtube]

Youtube has loads of similar low cost conversions.
 
fechter said:
The tractor needs to weigh more than the load to get traction. Ideally you want your water tank on the tractor.
Ideally , maybe....but that is not often practical and not the way farmers have been hauling loads even back with horse and carts.
The normal trick is to get weight transfer from the trailer to the tractor, by the correct location of the load relative to the trailer axle. The “drawbar hitch load” on an Ag trailer can be very high (tons ?)
[youtube]cvOnbnyE5RY[/youtube]
 
500 gallons is a big tank and would require a very large vehicle to carry onboard.

300 gallon trailer
325WT-600x336.jpg


500 gallon
WH500.jpg


As long as it is a short trip to the filling station, it may be better to make several trips with a smaller tank, or have two smaller tanks (one filling while one is being used) than to wait to fill one large tank depending on water source capacity.
 
500 gallons… what is the load capacity of water truck chassis? 5T?
Trailer or 6x6 with the lowest load height you can manage. And brakes! Lot of momentum on a grade!
For the ultimate. Trailer with powered wheels all connected to the vehicle controller;)
 
Hello,
I found this motor hub https://www.alibaba.com/product-detail/48v-1000w-20-inch-tractor-tire_1600229891700.html

I am trying to calculate how much NM should the motor hub have to be able to move a 1.4T vehicle at a 30% slope but i am having a hard time to calculate it properly. Based on my calculations 4 of these would be able to lift a 100kg vehicle which is obviously wrong.

Could there be anyone to help me sort out the right calculations needed to compute this? thanks in advance !
 
You could use the http://ebikes.ca/tools/simulator.html "backwards" to figure out the torque needed. Set up custom parts in there and conditions to give about the power you think you need, and see how much torque it takes to do this from a stall (zero RPM/MPH/kph), as well as power to maintain the speed you want under those conditions.

one possible simulation (unlikely to be accurate, only spent 10 seconds setting it up)
https://ebikes.ca/tools/simulator.html?wheel=20i&batt=cust_100_0.0_99999&cont=cust_99999_999999_0.00_V&hp=0&mass=1400&grade=30&black=load
Graph Syst A
Wheel Torq 654.4Nm
Mtr Power 722W
Load 1135W
Efficiency 1.0%
RPM 10.5 rpm
Electrical Syst A
Mtr Amps 712.2A
Batt Power 70152W
Batt Amps 701.5A
Batt Volts 100.0V
Performance Syst A
Acceleration -3.79 kph/s
Consumption 69571.8 Wh/km
Range 143 km
Overheat In 20 seconds
Final Temp >250 °C

FWIW, even if four of those might be able to do 100kg on that slope at some speed with the right gearing or wheel size, that's not even a tenth of the mass you're trying to move (1.4T should be 1400kg, assuming you mean metric ton, or 2205lbs) so you would need at least 14 of them.....

Assuming each one is actually only driven with the 1000w it's "rated" at that's 14kw of power...from 14 separate controllers, and probably 20kw+ from the battery(ies). No idea if that's how much it really needs (probably not even close to enough).

What are you planning on powering it with? How long does it have to supply that kind of power?
 
amberwolf thank you for your fast reply.

The thing is i also came to something like your number i.e. that these motors would be able to lift about 100kg at 30% slope. i.e. they would have to be at least 10X bigger to meet the need. However that sounds not very logical because, i mean what they make tracktor wheels for 100kg vehicles? doesn't make sense. Also from the logic point of view i haven't seen any motor hubs in the market producing anything more than 100 NM and last i have seen electric scooters with far less NM be able to lift a large man on a slope (150kg total), hence i feel that something is out of place in how i make the calculations. Asked also the producer of the wheel and they said they can support a 1600 kg max vehicle. Asked if they can share their calculations and they replied that their clients have tried. So, hence i am asking for help from the community to make the calculations properly. About the electric power, in theory it would a diesel power engine coupled with batteries, but if i can't be able to calculate the motor to weight association for a 30% slope, yet, would have to let it aside for next phase. About the gear ratio, they state that its a gear-less motor hub so all that is is 70to120nm per wheel.
Thanks in advance for anything that could help me understand the subject better
 
was able to extend your example as much
https://ebikes.ca/tools/simulator.html?wheel=20i&batt=cust_48_0.0_300&cont=cust_99999_999999_0.00_V&hp=0&mass=1400&grade=10&black=load&motor=cust_10.38_0.12_0.2_23_0.77_0.0185_0&autothrot=false&axis=rpm&frame=road
 
You wont be able to do it with simple , ungeared, hub motors using a practical wheel diameter.
You will need custom high power, geared reduction hub motors, or independent motors driving gearing to hubs…
….or a conventional tractor driveline with a separate Emotor driving through gearing to a axle/ differential to the wheels.
The key factors are wheel diameter and gearing ratio.
 
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