viability of building a 30-40 hp electric utility tractor?

[candersen10]

Needs:
- 4 wheel drive
- 30-40HP
- Under $15K
- Run for 8 hours on a charge
- full recharge over night
- ROPS
- Loader bucket
- 3 point hitch (front and back)
- PTO (Front and back)

Does anyone think such a project would be possible? I find it enormously frustrating that I'm just running down my fuel gauge every day and think that farming will have to start heading in this direction (or maybe hydrogen).

 

[zzvyb6]

If you had a course in Thermodynamics you would know the answer to your question. If you screwed off in class instead of studying, buy a mule or a team of horses. (Don't forget to feed them)...

 

[candersen10]

If you had a course in Thermodynamics you would know the answer to your question. If you screwed off in class instead of studying, buy a mule or a team of horses. (Don't forget to feed them)...

I'm afraid I have not taken any thermodynamics type classes outside of igneous and metamorphic petrology which applies to a vastly different field. What exactly do you mean? I have not heard of the laws of thermodynamics posing serious challenges to the construction of an electric tractor.

Mules and horses require about 1/4 of the land farmed to be set aside for feeding. I'm not interested in going back to pre-1900 style farming.

New Holland is building the NH2 and thus seems interested in Hydrogen technology coupled with electric drive trains. John Deere is working with UQM technologies on electric propulsion systems. Meanwhile, Cat makes the D7E which uses a diesel generator to run an electric motor undercarriage. This must indicate that there is at least some interest in producing electric tractors sometime soon.

 

[flusher]

Needs:
- 4 wheel drive
- 30-40HP
- Under $15K
- Run for 8 hours on a charge
- full recharge over night
- ROPS
- Loader bucket
- 3 point hitch (front and back)
- PTO (Front and back)

Does anyone think such a project would be possible? I find it enormously frustrating that I'm just running down my fuel gauge every day and think that farming will have to start heading in this direction (or maybe hydrogen).

Google "electric tractor" and you'll come up with things like this

Electric Tractors on Small Farms

I'd check out the specs on large electric powered fork lifts to get an idea of the state of the art in electric powered utility vehicles. Then see if you can fit tractor requirements into these specs.

 

[candersen10]

Google "electric tractor" and you'll come up with things like this

Electric Tractors on Small Farms

I'd check out the specs on large electric powered fork lifts to get an idea of the state of the art in electric powered utility vehicles. Then see if you can fit tractor requirements into these specs.

Thanks for the reply. I've looked through a good number of electric tractor projects online and it seems that everyone is building things in the 20 HP or less size range (I know that a 20 hp electric motor has different characteristics and potentially greater power than a diesel engine but still consider most of the current electric tractors out there to be too small to be practical on most farms).

I'm trying to get a sense of whether it would be possible to build a 30-40 hp electric tractor that would be marketable and practical. It seems to me that there is not enough discussion about alternative energy systems on farms.

 

[flusher]

Thanks for the reply. I've looked through a good number of electric tractor projects online and it seems that everyone is building things in the 20 HP or less size range (I know that a 20 hp electric motor has different characteristics and potentially greater power than a diesel engine but still consider most of the current electric tractors out there to be too small to be practical on most farms).

I'm trying to get a sense of whether it would be possible to build a 30-40 hp electric tractor that would be marketable and practical. It seems to me that there is not enough discussion about alternative energy systems on farms.

40 hp for 8 hours is 238 Kwh. At $0.10/Kwh for battery recharge that's about $24 per recharge (I used 524 Kwh last month and PG&E charged me $0.11531/Kwh) $24 would buy 8-10 gal of diesel. Small 30-40 hp diesel engines would burn about 1 gal/hr. So "recharge/refuel" cost looks like a wash, at least as a first cut ballpark estimate.

Battery pack is another story. The specific energy (Kwh/kilogram) is the important factor.

Honda EV+ Electric Vehicle Battery Facts

https://www.llnl.gov/str/pdfs/10_95.1.pdf

The best battery technology is zinc-air at 0.21 Kwh/kg. So that tractor battery pack would weigh 1133 kg (2493 lb). That's not too scary, since you want a 40 hp tractor to weigh at least 3500 lb.

Battery pack cost (see the LLNL report cited above):

($50 x 40hp x 0.746 kw/hp) + ($2/KWH x 238 Kwh) = $1492 + $476 = $1968,

which, conincidentally, is nearly identical to the cost Lawrence Livermore National Lab (LLNL) estimated for a battery to power a mid-size bus (see the second ref cited above).

So if the zinc-air battery ever goes into production, maybe an electric tractor is in the future of many TBNers.

 

[LBrown59]

Needs:
- 4 wheel drive
- 30-40HP
- Under $15K
- Run for 8 hours on a charge
- full recharge over night
- ROPS
- Loader bucket
- 3 point hitch (front and back)
- PTO (Front and back)

Does anyone think such a project would be possible?
*I find it enormously frustrating that I'm just running down my fuel gauge every day and think that farming will have to start heading in this direction (or maybe hydrogen).

*Are you using gas or diesel.

 

[candersen10]

*Are you using gas or diesel.

I have a John Deere 6430 premium, it's just about the most fuel efficient tractor for its class and they are using them in Europe where diesel is much more expensive. Nonetheless, last summer, when diesel was around 5 bucks a gallon, tillage and other tasks became extremely expensive.

I have a CT332, 5325, TN75, and 1710 HC as well. All of these machines are no where near as efficient as I would like. The CT332 and 5325 both have big 5 cylinder turbo diesels which use several gallons per hour.

Agriculture is just enormously fuel dependent. Nitrogen fertilizer is produced with natural gas and energy from other fossil fuel sources, transport is enormously fuel dependent, and tractors are enormously fuel dependent. There will have to be a paradigm shift in the equipment industry in the near future as fuel prices rise and diesel becomes scarce. One would think that with this change on the near horizon, some companies would be out there really producing revolutionary new products. From what I can see, however, there are just a few small companies out there looking at producing small scale products that are no where near viable.

 

[BobRip]

Batteries have always been the limiting factor for electric vehicles and since motors and controllers have gotten better then batteries are the really big remaining issue. Batteries hold about 4% as much energy at best as gasoline of the same weight. A practical battery is even worse. The GM Volt will go 40 miles on a battery charge. The battery weighs 500 lbs. It will also go 40 miles on a gallon of gas at 5 lbs. That's about 100 to 1 ratio. Also batteries wear out. The best today get about 2000 charge/discharge cycles. At once a day full use this is about 5.5 years. Oh, and they won't really last that long. Batteries are devices with complex chemical reactions in then and they only work as defined at certain conditions. When they are cold, older, charged non-optimally, subject to vibration, heated, etc. they change their behavior. Why not use methane, which you can produce on your farm.

 

[BobRip]

Batteries have always been the limiting factor for electric vehicles and since motors and controllers have gotten better then batteries are the really big remaining issue. Batteries hold about 4% as much energy at best as gasoline of the same weight. A practical battery is even worse. The GM Volt will go 40 miles on a battery charge. The battery weighs 500 lbs. It will also go 40 miles on a gallon of gas at 5 lbs. That's about 100 to 1 ratio. Also batteries wear out. The best today get about 2000 charge/discharge cycles. At once a day full use this is about 5.5 years. Oh, and they won't really last that long. Batteries are devices with complex chemical reactions in then and they only work as defined at certain conditions. When they are cold, older, charged non-optimally, subject to vibration, heated, etc. they change their behavior. Why not use methane, which you can produce on your farm. Sorry for the negative comments, I spent 15 years developing battery powerd products and learned a lot of bad things about batteries. Tom Edison once said "When you talk about batteries, you are always lying". This means that their behavior is so complex that you can never tell the whole truth. Of course I must be lying here.