Riding Mowers -Gas/Electric?

[Jim Rosenow]

This discussion started because I mentioned, in a related post, converting a riding mower to electric, to use the massive extra summer electricity we have from our off-grid solar. Opinions varied, and opened into an over-all discussion on larger riding mowers. I found the long response by flyingcheesehead in the other post most informative. Thank you!

The initial subject of the conversion question is our Steiner 430. I had never heard of Steiner until I moved to Ohio, practically next door to where they started. It's a beast. 4WD, and I've outfitted it with tandem wheels all around and a cab to keep the sun and snow off. It pushes a front-mounted 72-inch mower, and over the years we've accumulated a front-mounted bucket, 4-foot tiller and snowblower, and a 5-foot articulating dirt/snow plow. Truly a jack of all trades. If I could find another one, cheap (not noted in the Steiner vocabulary exactly), I'd try to convert to 48v electric.

I tried to load a pic, but it wouldn't take. Anybody know what an .heic file is? Never mind...got it.

Jim

 

[flyingron]

HEIC is the new JPEG essentially. Most notable producer of these right now are iPhones.

There are lots of suppliers of EV conversion stuff (mostly for cars but probably quite applicable to you). It's not going to be cheap. You'll have to mount the batteries somewhere. Fortunately, from your picture it looks like you have weights on the back of the tractor already you can probably swap out for that.

 

[Jim K]

I've never head of your Steiner either, but it looks a lot like the Ventrac:

which I also hadn't heard of until I started watching Tractor Time with Tim. If you go to his YT, you'll find a few videos he did about "Solectrac". It was a fairly short lived electric utility tractor in that 25ish HP range. It worked fairly well, but there were a few shortcomings that made it seem like the engineers had never used a tractor before. For example, the PTO spun backwards in reverse. In the end it looks like it might've been a government subsidy harvesting scam, but the reason I bring it up is there are a fair number of these things that are now orphaned and ripe to be harvested for batteries, motor, and controllers that would work great to convert another utility tractor. Or just use it as is with its shortcomings. It looked like it would do most of what any homeowner would need from it.

Case IH released an electric in the 75HP size range, but that's really too big for a yard. JD is working on it. They actually had a technology demonstrator that infamously caught fire at a trade show a year or so ago. All this to say the homeowner type "subcompact utility tractor (SCUT)" market is very close to having viable electric machines.

 

[GoFly]

there are a fair number of these things that are now orphaned and ripe to be harvested for batteries, motor, and controllers that would work great to convert another utility tractor.

Or an airplane tug

 

[Jim K]

Or an airplane tug

FWIW the 48V electric aircraft tug market already has a compelling entry that doubles as airport transportation:

 

[GoFly]

Even better. Any truth to the rumor that those stickers make it faster?

 

[Jim Rosenow]

I've never head of your Steiner either, but it looks a lot like the Ventrac:
View attachment 132719
which I also hadn't heard of until I started watching Tractor Time with Tim. If you go to his YT, you'll find a few videos he did about "Solectrac". It was a fairly short lived electric utility tractor in that 25ish HP range. It worked fairly well, but there were a few shortcomings that made it seem like the engineers had never used a tractor before. For example, the PTO spun backwards in reverse. In the end it looks like it might've been a government subsidy harvesting scam, but the reason I bring it up is there are a fair number of these things that are now orphaned and ripe to be harvested for batteries, motor, and controllers that would work great to convert another utility tractor. Or just use it as is with its shortcomings. It looked like it would do most of what any homeowner would need from it.

Case IH released an electric in the 75HP size range, but that's really too big for a yard. JD is working on it. They actually had a technology demonstrator that infamously caught fire at a trade show a year or so ago. All this to say the homeowner type "subcompact utility tractor (SCUT)" market is very close to having viable electric machines.

As I understand the local history, the Ventrac is actually the red-headed step-child of the Steiner. Poppa Steiner started the Steiner brand on his farm in Orrville, Ohio (8 miles east of kbjj). He had several sons who, when he died, were unable to come to an arrangement on the business. Thru some unknowable to me legal machination, some of the boys took part of the business and went off. Some of the boys stayed in Orrville and continued on as Steiner. Thus enter the Ventrac brand. Ventrac has been sold and gone corporate. Last I knew, Steiners are still made in Orville by family.

Virtually all of the Steiner/Ventrac accessories are interchangeable on their 2-point front hitch. Mine's a 1999 with 1900-ish hours. On it's second engine and going strong. I just got off it. Love the thing....especially the local roots!

I'm going to have to do some research on the Solectrac....sounds awesome! Thank you!

 

[Jim K]

Even better. Any truth to the rumor that those stickers make it faster?

100%

 

[Capt. Geoffrey Thorpe]

 

[flyingcheesehead]

This discussion started because I mentioned, in a related post, converting a riding mower to electric, to use the massive extra summer electricity we have from our off-grid solar. Opinions varied, and opened into an over-all discussion on larger riding mowers. I found the long response by flyingcheesehead in the other post most informative. Thank you!

You're welcome! Thanks for posting over there that you were starting a new thread so I could come find this.

The initial subject of the conversion question is our Steiner 430. I had never heard of Steiner until I moved to Ohio, practically next door to where they started. It's a beast. 4WD, and I've outfitted it with tandem wheels all around and a cab to keep the sun and snow off. It pushes a front-mounted 72-inch mower, and over the years we've accumulated a front-mounted bucket, 4-foot tiller and snowblower, and a 5-foot articulating dirt/snow plow. Truly a jack of all trades. If I could find another one, cheap (not noted in the Steiner vocabulary exactly), I'd try to convert to 48v electric.

Any particular reason for 48V? I think you might do better at a higher voltage. V=IR and P=VI=I2R. So, for the same power, if you double the voltage you halve the current. Wire size needed is based on current, so you can save yourself a lot of money on copper by using a higher voltage.

I have seen tractor conversions that were done with plain old lead-acid car/marine batteries, but you're not going to get the amount of work done that you want to with that setup. You're probably going to be a lot happier with a conversion that uses EV batteries - If you watch this video, they talk about a site where you can purchase those:

I've been kind of keeping an eye out for the right size tractor but with a bad engine so I can do a conversion. Unfortunately, the engines on the JD SCUTs seem to be fairly bulletproof so they're fairly rare.

There are lots of suppliers of EV conversion stuff (mostly for cars but probably quite applicable to you). It's not going to be cheap. You'll have to mount the batteries somewhere. Fortunately, from your picture it looks like you have weights on the back of the tractor already you can probably swap out for that.

Engines, transmissions, fuel tanks, etc all take up quite a bit of room. If you fill the available space with batteries, you can get a reasonable amount of work done before charging.

I started watching Tractor Time with Tim. If you go to his YT, you'll find a few videos he did about "Solectrac". It was a fairly short lived electric utility tractor in that 25ish HP range.

Was?

It worked fairly well, but there were a few shortcomings that made it seem like the engineers had never used a tractor before. For example, the PTO spun backwards in reverse.

‍ That could be bad!

Unfortunately, I think the venn diagram of the tractor crowd and the EV crowd has a VERY small intersection. Most of the electric stuff I've seen is either not particularly practical from the tractor side of things (designed by the EV circle), or has craptastic specifications as if it was designed to fail (designed by the gearhead tractor circle). As part of the small intersection of the two, I am convinced that it is possible to make a great electric tractor, but unfortunately, nobody wants to do it. It's following the same pattern as the early days of our current EV resurgence: New manufacturers who want to make it happen but don't know how to make the thing they're trying to replace, and existing manufacturers who are actively trying to make it fail.

Who wants to invest in my EV tractor startup? It'll be the Tesla of the tractor world...

In the end it looks like it might've been a government subsidy harvesting scam, but the reason I bring it up is there are a fair number of these things that are now orphaned

Again with the past tense - Is Solectrac out of business? I can only find things about them restructuring, which sounds like it was mainly eliminating the dealer network deal with a different company. As far as I can tell, they're still going and are now selling direct to consumer which makes a lot more sense than trying to put demo units out at dealers when you're only selling 15 per month and your goal is 30 per month.

Or just use it as is with its shortcomings. It looked like it would do most of what any homeowner would need from it.

Biggest shortcoming, IMO, is the price. I don't think the tractor market is large enough to get the same economies of scale with battery production as the on-road EV market. The only way to make up for that is to use off the shelf components or make a deal with an EV maker or EV battery producer, and that doesn't seem to be happening yet.

JD is working on it. They actually had a technology demonstrator that infamously caught fire at a trade show a year or so ago.

So, JD has a prototype they called the "1RE" which seems to be an electric 1 series but they've been very quiet about it.

However, I couldn't find anything about JD having a fire? DeWalt had an electric zero turn burn up at a show a couple years ago it looks like, but I haven't heard of an issue with JD. Mainly because I don't think it even has batteries on it yet. ‍

I sure did find a lot of fossil-fuel John Deeres burning up though!

All this to say the homeowner type "subcompact utility tractor (SCUT)" market is very close to having viable electric machines.

I sure hope you're right, and I hope they don't suck.

My wishlist for an e-SCUT:

1) Compatibility with mechanical attachments. That means a 540RPM rear PTO, a 3-point hitch, and hydraulics.
2) Availability of electrical attachments. Things like mid mount mowers and front snowblowers tend to be proprietary anyway, so might as well make it electrical and use the advantages that gives you.
3) Ease of swapping attachments. This is the whole reason the John Deere stuff is interesting to me, they're the best at this right now. The more versatile a tractor is, the more useful it is, and the less time it takes to swap attachments, the more versatile the tractor. I would love to be able to mow the lawn, use a broom to de-thatch the lawn, pick up the clippings from both of the above, move several cubic yards of mulch, grind a stump, dig a hole, and use a grapple to move tree carcasses around, all in one day.
4) Varying battery capacities, and the ability to move and swap batteries to some extent. I feel like there should be an on-board battery that can take care of easy-medium work. There should also be an optional "battery bucket" that functions as a weight bucket, can be mechanically lifted by the rear 3 point hitch and whatever lift is available at the front of the tractor, and can both recharge the onboard battery during use as well as provide power to run the tractor.
5) Liquid cooled batteries and a smart Battery Management System for longevity.
6) Preferably, able to be charged using a NACS plug to be able to take advantage of existing EV charging technology, and the chargers I already have in my garage.
7) Reasonable charge times, preferably such that having a pair of Battery Buckets would allow for something close to unlimited runtime (charge 1/use 1).
8) A reasonable price tag. The purchase price can be higher than a fossil fuel equivalent if necessary, but the fuel savings alone need to pencil out to a payback within the first 5-8 years. If you're an existing manufacturer, you don't need to reinvent the wheel, just put a new powertrain on an existing model (like JD is apparently doing with the 1RE).

 

[flyingcheesehead]

BTW @Jim Rosenow you should start by figuring out what size battery you need. Is your Steiner diesel or gas? How much fuel do you go through per mow?

My Simplicity Legacy is 25hp gasoline. 25hp = 18.64kW but of course it's not running at 100% power all the time!

I figure it takes me about 3-3.5 gallons of gas to mow my two acres. That means a total of about 101-118kWh; however, a gasoline engine, especially one on one of these tractors, is only going to be about 20-25% efficient, so the real amount of energy put into work is maybe 25kWh. Figuring 90% motor efficiency, I need about a 28kWh battery. With a nice reserve, call it 35kWh. This would do the trick nicely: https://www.greentecauto.com/hybrid...rgy/catl-202-86v-173ah-35kwh-lfp-battery-pack And that's a steal at $1500. It says regular price is $2200, and even that is only $63/kWh. Just needs a BMS with liquid cooling capability.

 

[Jim Rosenow]

BTW @Jim Rosenow you should start by figuring out what size battery you need. Is your Steiner diesel or gas? How much fuel do you go through per mow?

My Simplicity Legacy is 25hp gasoline. 25hp = 18.64kW but of course it's not running at 100% power all the time!

I figure it takes me about 3-3.5 gallons of gas to mow my two acres. That means a total of about 101-118kWh; however, a gasoline engine, especially one on one of these tractors, is only going to be about 20-25% efficient, so the real amount of energy put into work is maybe 25kWh. Figuring 90% motor efficiency, I need about a 28kWh battery. With a nice reserve, call it 35kWh. This would do the trick nicely: https://www.greentecauto.com/hybrid...rgy/catl-202-86v-173ah-35kwh-lfp-battery-pack And that's a steal at $1500. It says regular price is $2200, and even that is only $63/kWh. Just needs a BMS with liquid cooling capability.

You are WAY ahead of me on the electric tractor curve. I just started researching the whole project, hence the initial question. The 48v came out of my limited experience in the residential solar area, where 48v seems standard. I come seeking knowledge. Are there applicable forums, so we don't put these airplane guys to sleep?

 

[Jim Rosenow]

HEIC is the new JPEG essentially. Most notable producer of these right now are iPhones.

There are lots of suppliers of EV conversion stuff (mostly for cars but probably quite applicable to you). It's not going to be cheap. You'll have to mount the batteries somewhere. Fortunately, from your picture it looks like you have weights on the back of the tractor already you can probably swap out for that.

Good observational skills Ron! I was thinking of bolting batteries in where the weights are!....Maybe something quick disconnect to swap packs?

 

[Jim K]

You're welcome! Thanks for posting over there that you were starting a new thread so I could come find this.

Any particular reason for 48V? I think you might do better at a higher voltage. V=IR and P=VI=I2R. So, for the same power, if you double the voltage you halve the current. Wire size needed is based on current, so you can save yourself a lot of money on copper by using a higher voltage.

I have seen tractor conversions that were done with plain old lead-acid car/marine batteries, but you're not going to get the amount of work done that you want to with that setup. You're probably going to be a lot happier with a conversion that uses EV batteries - If you watch this video, they talk about a site where you can purchase those:

I've been kind of keeping an eye out for the right size tractor but with a bad engine so I can do a conversion. Unfortunately, the engines on the JD SCUTs seem to be fairly bulletproof so they're fairly rare.

Engines, transmissions, fuel tanks, etc all take up quite a bit of room. If you fill the available space with batteries, you can get a reasonable amount of work done before charging.

Was?

‍ That could be bad!

Unfortunately, I think the venn diagram of the tractor crowd and the EV crowd has a VERY small intersection. Most of the electric stuff I've seen is either not particularly practical from the tractor side of things (designed by the EV circle), or has craptastic specifications as if it was designed to fail (designed by the gearhead tractor circle). As part of the small intersection of the two, I am convinced that it is possible to make a great electric tractor, but unfortunately, nobody wants to do it. It's following the same pattern as the early days of our current EV resurgence: New manufacturers who want to make it happen but don't know how to make the thing they're trying to replace, and existing manufacturers who are actively trying to make it fail.

Who wants to invest in my EV tractor startup? It'll be the Tesla of the tractor world...

Again with the past tense - Is Solectrac out of business? I can only find things about them restructuring, which sounds like it was mainly eliminating the dealer network deal with a different company. As far as I can tell, they're still going and are now selling direct to consumer which makes a lot more sense than trying to put demo units out at dealers when you're only selling 15 per month and your goal is 30 per month.

Biggest shortcoming, IMO, is the price. I don't think the tractor market is large enough to get the same economies of scale with battery production as the on-road EV market. The only way to make up for that is to use off the shelf components or make a deal with an EV maker or EV battery producer, and that doesn't seem to be happening yet.

So, JD has a prototype they called the "1RE" which seems to be an electric 1 series but they've been very quiet about it.

However, I couldn't find anything about JD having a fire? DeWalt had an electric zero turn burn up at a show a couple years ago it looks like, but I haven't heard of an issue with JD. Mainly because I don't think it even has batteries on it yet. ‍

I sure did find a lot of fossil-fuel John Deeres burning up though!



I sure hope you're right, and I hope they don't suck.

My wishlist for an e-SCUT:

1) Compatibility with mechanical attachments. That means a 540RPM rear PTO, a 3-point hitch, and hydraulics.
2) Availability of electrical attachments. Things like mid mount mowers and front snowblowers tend to be proprietary anyway, so might as well make it electrical and use the advantages that gives you.
3) Ease of swapping attachments. This is the whole reason the John Deere stuff is interesting to me, they're the best at this right now. The more versatile a tractor is, the more useful it is, and the less time it takes to swap attachments, the more versatile the tractor. I would love to be able to mow the lawn, use a broom to de-thatch the lawn, pick up the clippings from both of the above, move several cubic yards of mulch, grind a stump, dig a hole, and use a grapple to move tree carcasses around, all in one day.
4) Varying battery capacities, and the ability to move and swap batteries to some extent. I feel like there should be an on-board battery that can take care of easy-medium work. There should also be an optional "battery bucket" that functions as a weight bucket, can be mechanically lifted by the rear 3 point hitch and whatever lift is available at the front of the tractor, and can both recharge the onboard battery during use as well as provide power to run the tractor.
5) Liquid cooled batteries and a smart Battery Management System for longevity.
6) Preferably, able to be charged using a NACS plug to be able to take advantage of existing EV charging technology, and the chargers I already have in my garage.
7) Reasonable charge times, preferably such that having a pair of Battery Buckets would allow for something close to unlimited runtime (charge 1/use 1).
8) A reasonable price tag. The purchase price can be higher than a fossil fuel equivalent if necessary, but the fuel savings alone need to pencil out to a payback within the first 5-8 years. If you're an existing manufacturer, you don't need to reinvent the wheel, just put a new powertrain on an existing model (like JD is apparently doing with the 1RE).

It's possible it was the Dewalt mower and I'm mis-remembering. I have a memory of a green tractor behind a tent on fire, but I can't find it in a quick search either.

My sum total of knowledge about solectrac comes from TTWT. I'd encourage you to watch this one:

He goes over some of the shenanigans. Possible they are trying to restructure, but I think they are going to need a better product to be successful. I do think there's a market for a well engineered machine, particularly the SCUTs. I'd think that for the average homeowner, hauling diesel around would be a real PITA. I remember how much I hated hauling gas for my little push mower when I lived in town. Can't imagine feeding a 25hp tractor with jugs.

 

[flyingcheesehead]

You are WAY ahead of me on the electric tractor curve. I just started researching the whole project, hence the initial question. The 48v came out of my limited experience in the residential solar area, where 48v seems standard. I come seeking knowledge. Are there applicable forums, so we don't put these airplane guys to sleep?

You must be new to PoA if you haven't noticed the amount of off-topic discussion that happens here.

I'm not in any forums for such things, but I did find this: https://www.diyelectriccar.com/forums/

Possible they are trying to restructure, but I think they are going to need a better product to be successful. I do think there's a market for a well engineered machine, particularly the SCUTs.

Yes on both counts.

I'd think that for the average homeowner, hauling diesel around would be a real PITA. I remember how much I hated hauling gas for my little push mower when I lived in town. Can't imagine feeding a 25hp tractor with jugs.

Every other week or so, I run up to HXF in my car (~25-30 min drive) because that's the closest I can buy ethanol free gas. 10 gallons each trip. Worth it to make my electric car smell like gas.

Also, maybe an excuse to see what's flying, who's flying, and get distracted by that for a bit. I've seen hot air balloons, there's lots of glider activity, Steve Krog's all-Cub flight school is there, and last time I met a guy who builds Howard wings there and got to see his shop, which was freaking amazing.

 

[Randomskylane]

Quote: I would love to be able to mow the lawn, use a broom to de-thatch the lawn, pick up the clippings from both of the above, move several cubic yards of mulch, grind a stump, dig a hole, and use a grapple to move tree carcasses around, all in one day.

I was with you until you said in one day instead of two weeks. It’s ok, I found a couch to nap on

 

[Jim Rosenow]

My sum total of knowledge about solectrac comes from TTWT. I'd encourage you to watch this. I'd think that for the average homeowner, hauling diesel around would be a real PITA. I remember how much I hated hauling gas for my little push mower when I lived in town. Can't imagine feeding a 25hp tractor with jugs.

Got a chuckle out of this....been feeding the Steiner (23 hp maybe?) non-alcohol gas out of a set of the old mil-style cans for years.

Ironically, I've got 100 or so gallons of Jet-A/diesel mix in 55 gallon drums in reserve for the MEP803 gennie that had been our PoCo back-up til solar. Tried to get the dealer to diesel-ize the Steiner when we put the new engine, but was told factory wouldn't let them. Never did figure that out.

 

[SoonerAviator]

Any EV tractor really ought to be designed more like a modern EV skateboard platform of sorts. Still going to need the beefy bottom end but form factor doesn't have to look as much like a current ICE variant because some of those design constraints won't be there. Carrying the weight low is always a priority so getting the batteries in between frame rails seems like a win- win.

I think it would be better to combine the utility of a tractor with attachments like a skid steer. Have a rear 3pt with 540 pto, but leave the front and mid- mount stuff to pure hydraulics. If the EV can power a beefy hydraulic pump, you light even be able to run skid steer implements instead.

I do agree that any ballast buckets should just be aux battery banks to add range.

 

[flyingcheesehead]

Any EV tractor really ought to be designed more like a modern EV skateboard platform of sorts. Still going to need the beefy bottom end but form factor doesn't have to look as much like a current ICE variant because some of those design constraints won't be there. Carrying the weight low is always a priority so getting the batteries in between frame rails seems like a win- win.

I had initially thought up a design kinda like that, but maybe I'm not creative enough for the "doesn't have to look as much like a current ICE variant"... I keep thinking about having bigger/more batteries and IMO limiting yourself to frame height means the battery is going to be kinda small and then what do you do with all the extra space in front of you that's higher up?

 

[CartonianAviation]

Depending on what you are looking for, i have a few ideas. If you want a Commercial Zero-Turn, i suggest a Scag, somewhat expensive, but very high quality

 

[CJones]

8) A reasonable price tag. The purchase price can be higher than a fossil fuel equivalent if necessary, but the fuel savings alone need to pencil out to a payback within the first 5-8 years. If you're an existing manufacturer, you don't need to reinvent the wheel, just put a new powertrain on an existing model (like JD is apparently doing with the 1RE).

I think this one will be hard to achieve. We have used my dad's little MF GC1710 for WAY more than it was designed for, and we barely burn any diesel with it. I have run it harder than most people would run it for several hours straight (first sub-soiling our rock hard red clay garden spot as deep as the shank would go (this is traditionally known for ripping the guts out of full-sized tractors), then tilling it back down smooth with 4' PTO tiller, then bucketing several yards of compost/mulch onto said garden, then tilling that in in what is now heavy soil). Probably 5-6 hrs of stead full-power RPM which includes 2-3 hours of bogged down hard pulling and it still only burned a few gallons of diesel. That's way more than the average homeowner will do with their tractor with a belly mower and moving some pine chips. It's hard to make up the ROI based on fuel alone, even with $6/gal on-road diesel.

 

[SoonerAviator]

I had initially thought up a design kinda like that, but maybe I'm not creative enough for the "doesn't have to look as much like a current ICE variant"... I keep thinking about having bigger/more batteries and IMO limiting yourself to frame height means the battery is going to be kinda small and then what do you do with all the extra space in front of you that's higher up?

I don't mean that you're solely limited to frame width, just that the space occupied by the engine in a traditional tractor can be re-designed to maybe put the operator more central and keep the batteries low as opposed to just taking an existing frame and stacking a box of batteries where the engine normally goes. Some of that requires some good design-engineering so that you maintain good clearance and visibility for FELs and clear view of 3-pt implements. I'm not sure that you'd need more than 2 electric drives for the rears, but having something akin to a differential lock would be highly necessary, which may have to be electronically simulated. The positive thing for the compact tractor class (really stuff under 25HP) is that most of them don't spend a ton of time at high RPM/load. Running around with a FEL moving dirt/etc. around doesn't require a lot of battery power. Brush hogging or mowing is where the battery capacity comes into play, I'd think. We might brush hog a few acres that takes a couple hours, but we don't have a need to run a tractor for 4 or 5 hours straight. Once you get into larger tractors where they're doing farm work or lots of off-site work, the battery capacity becomes a much bigger issue.

 

[flyingcheesehead]

I think this one will be hard to achieve. We have used my dad's little MF GC1710 for WAY more than it was designed for, and we barely burn any diesel with it. I have run it harder than most people would run it for several hours straight (first sub-soiling our rock hard red clay garden spot as deep as the shank would go (this is traditionally known for ripping the guts out of full-sized tractors), then tilling it back down smooth with 4' PTO tiller, then bucketing several yards of compost/mulch onto said garden, then tilling that in in what is now heavy soil). Probably 5-6 hrs of stead full-power RPM which includes 2-3 hours of bogged down hard pulling and it still only burned a few gallons of diesel. That's way more than the average homeowner will do with their tractor with a belly mower and moving some pine chips. It's hard to make up the ROI based on fuel alone, even with $6/gal on-road diesel.

Correct - I probably burn a grand total of 100 gallons or so per year, and that's gasoline. Diesel is likely to be less.

The issue is that it's easy to calculate savings from fuel, and really hard to calculate savings from maintenance. I don't think a lot of people know what they spend on maintenance, in either time or money, unless they're a working farm with good accounting practices, and those folks aren't likely to be interested in a subcompact utility tractor. If someone can't see that they're going to spend the same or less money, it's going to be harder for them to take the leap to switch to electric.

I don't mean that you're solely limited to frame width, just that the space occupied by the engine in a traditional tractor can be re-designed to maybe put the operator more central and keep the batteries low as opposed to just taking an existing frame and stacking a box of batteries where the engine normally goes.

I'm just not sure that buys you much. One thing that keeps me from buying a modern zero turn is that I wish they still had zero turns with the mower deck out in front rather than pretty much underneath you - I have a lot of conifers on my property that I need to mow under the edges of, and that either means getting scratched up or wearing clothes that are far too warm for the weather. If I could have a zero turn with a front mount deck, I'd be all over it.

Now, if we can figure out omniwheels that work for turf and dirt, we could really do some interesting stuff... However, IMO the "weird" needs to be separated from the "electric" if it's going to take off. There are some interesting possibilities with a rear-entry operator station and making things balanced, but again, weird. I think the best possibility for success is a tractor that is roughly shaped like current tractors, with batteries in between the frame rails pretty much all the way front to back, plus under the footrests for some extra capacity in the low-CG area. I do think that you'll still need to stack some batteries in the area that now houses the engine, and probably put the control and cooling systems on the top assuming they're lighter and less dense. You could improve visibility over the front, though.

Some of that requires some good design-engineering so that you maintain good clearance and visibility for FELs and clear view of 3-pt implements. I'm not sure that you'd need more than 2 electric drives for the rears, but having something akin to a differential lock would be highly necessary, which may have to be electronically simulated.

That is easily solved in software. When a wheel slips, you slow it down. Driving the front wheels could be done hydraulically, and I think many/most SCUTs already do it that way, or you could put some motors up there as well.

The positive thing for the compact tractor class (really stuff under 25HP) is that most of them don't spend a ton of time at high RPM/load. Running around with a FEL moving dirt/etc. around doesn't require a lot of battery power. Brush hogging or mowing is where the battery capacity comes into play, I'd think. We might brush hog a few acres that takes a couple hours, but we don't have a need to run a tractor for 4 or 5 hours straight. Once you get into larger tractors where they're doing farm work or lots of off-site work, the battery capacity becomes a much bigger issue.

Yes. However, you also generally have a much larger tractor and more space to put batteries in it. But, the larger the tractor, the less worthwhile an electric version is IMO. Maybe it'll be practical someday, but I wouldn't bet on it in my lifetime. Diesel-electric hybrid is much more likely, but I'm not sure how worthwhile that would be.

 

[SoonerAviator]

Correct - I probably burn a grand total of 100 gallons or so per year, and that's gasoline. Diesel is likely to be less.

The issue is that it's easy to calculate savings from fuel, and really hard to calculate savings from maintenance. I don't think a lot of people know what they spend on maintenance, in either time or money, unless they're a working farm with good accounting practices, and those folks aren't likely to be interested in a subcompact utility tractor. If someone can't see that they're going to spend the same or less money, it's going to be harder for them to take the leap to switch to electric.

I'm just not sure that buys you much. One thing that keeps me from buying a modern zero turn is that I wish they still had zero turns with the mower deck out in front rather than pretty much underneath you - I have a lot of conifers on my property that I need to mow under the edges of, and that either means getting scratched up or wearing clothes that are far too warm for the weather. If I could have a zero turn with a front mount deck, I'd be all over it.

Now, if we can figure out omniwheels that work for turf and dirt, we could really do some interesting stuff... However, IMO the "weird" needs to be separated from the "electric" if it's going to take off. There are some interesting possibilities with a rear-entry operator station and making things balanced, but again, weird. I think the best possibility for success is a tractor that is roughly shaped like current tractors, with batteries in between the frame rails pretty much all the way front to back, plus under the footrests for some extra capacity in the low-CG area. I do think that you'll still need to stack some batteries in the area that now houses the engine, and probably put the control and cooling systems on the top assuming they're lighter and less dense. You could improve visibility over the front, though.

That is easily solved in software. When a wheel slips, you slow it down. Driving the front wheels could be done hydraulically, and I think many/most SCUTs already do it that way, or you could put some motors up there as well.

Yes. However, you also generally have a much larger tractor and more space to put batteries in it. But, the larger the tractor, the less worthwhile an electric version is IMO. Maybe it'll be practical someday, but I wouldn't bet on it in my lifetime. Diesel-electric hybrid is much more likely, but I'm not sure how worthwhile that would be.

You can buy Zero-Turns with front mount decks all day long. Grasshopper is probably one of the most well-known in that space as that has been their design for a long time, and Ferris makes a model or two as well.. Kubota still makes 2 or 3 models, which you see in many golf/park maintenance applications. As much as a "software" fix for slipping wheels sounds good, I'd be very wary of trying to get the electronics doing too much on a tractor-application. A common complaint from owners of modern tractors is the inclusion of more and more electronic gizmos that end up being the source of failures/frustration versus good old mechanical controls. Tractors being used/abused out in the elements tends to be less conducive to the longevity of electronics. There are also instances where I want one wheel to continue forward while I brake or let the other "slip" to help tighten a turn. It's tough to have electronics know which you want to do, where a simple foot pedal can manually trigger than same action.

Also with an EV being battery capacity limited, I'd probably be trying to eliminate as many power conversions as possible; so the more things running an individual electric motor the better, rather than numerous hydraulic pumps and the power losses associated with that.

 

[flyingcheesehead]

You can buy Zero-Turns with front mount decks all day long.

I haven't seen an electric one yet. Everything is mid mount.

As much as a "software" fix for slipping wheels sounds good, I'd be very wary of trying to get the electronics doing too much on a tractor-application.

Um... On an electric tractor it's almost a necessity. Sure, it would be possible to do analog circuits, DC motors, and make it "simple" but it wouldn't be any easier to fix in the field and would be more prone to breaking in the first place. This isn't a hard thing to do - My RWD Tesla works great even in Wisconsin winters, and does not spin tires.

A common complaint from owners of modern tractors is the inclusion of more and more electronic gizmos that end up being the source of failures/frustration versus good old mechanical controls.

A mechanical "differential lock" on an electric tractor would likely make a single motor with a hydrostatic transmission and a traditional diff lock a better option - But that would also make it heavier, more complex and expensive to build, and take up room that could better be used for batteries.

The issue isn't that something is electronic - The issue is that tractor manufacturers are making stuff that breaks. That's because they're a lot better at mechanical stuff than electronic stuff.

Tractors being used/abused out in the elements tends to be less conducive to the longevity of electronics.

Yes, but that's merely a design consideration. The electronics need to be protected from dirt, heat, etc... And so do the batteries.

There are also instances where I want one wheel to continue forward while I brake or let the other "slip" to help tighten a turn. It's tough to have electronics know which you want to do, where a simple foot pedal can manually trigger than same action.

Why couldn't you do the same thing with electronics? Two "brake" pedals that can stop the motor on that side and let you turn in place if you want, probably linked to a mechanical brake further down in their travel. That's pretty trivial to implement in the grand scheme of things. Why would it be tough for electronics to know what you want to do?

Also with an EV being battery capacity limited, I'd probably be trying to eliminate as many power conversions as possible; so the more things running an individual electric motor the better, rather than numerous hydraulic pumps and the power losses associated with that.

True. I mainly look at hydraulics as a way to make v1 easier to implement. Sure, you could make a front end loader with linear actuators, but it's a bunch easier to use an off the shelf hydraulic one. Same with driving front wheels, lifting attachments, etc.

It's hard enough to pioneer things like this - That's why Tesla started by just converting Lotus Elise gliders for the original Tesla Roadster, and the clean-sheet Model S was the second product. I would imagine that if Eclipse had decided to use off-the-shelf avionics and build methods instead of trying to do their own thing and get friction stir welding approved, they may have been more successful at getting their jet to market.

 

[SoonerAviator]

I haven't seen an electric one yet. Everything is mid mount.

Sorry, didn't realize you were also referring to having an EV mower/tractor, just that you wanted a front-mount deck.

Um... On an electric tractor it's almost a necessity. Sure, it would be possible to do analog circuits, DC motors, and make it "simple" but it wouldn't be any easier to fix in the field and would be more prone to breaking in the first place. This isn't a hard thing to do - My RWD Tesla works great even in Wisconsin winters, and does not spin tires.

I wasn't implying that the whole thing be devoid of all electronics, just that it would probably be best to keep it to a minimum for basic controllers. Tractors are generally very simple machines, so adding failure points and making repair diagnosis more complex probably isn't in the best interest of the consumer.

A mechanical "differential lock" on an electric tractor would likely make a single motor with a hydrostatic transmission and a traditional diff lock a better option - But that would also make it heavier, more complex and expensive to build, and take up room that could better be used for batteries.

Again, I'm just talking about a diff lock "pedal" which allows the user to select when you need both wheels locked/engaged rather than using computer logic to guess when you want it. It need not be paired with a differential like on a standard tractor.

Why couldn't you do the same thing with electronics? Two "brake" pedals that can stop the motor on that side and let you turn in place if you want, probably linked to a mechanical brake further down in their travel. That's pretty trivial to implement in the grand scheme of things. Why would it be tough for electronics to know what you want to do?

Same reason that EVs aren't all that common in off-roading. I believe there are times when you are doing things with a tractor that are varied and the "computer logic" wouldn't be able to discern what you wanted it to do. Think traction control on a car when you're trying to get un-stuck or get up a snow-covered hill: normally it's trying to stop wheel spin, but in that situation I WANT wheelspin. So then you have to disable it. Yes, then they made "snow mode" for some cars, but even then it may not behave how you want it to. Same goes for a tractor when you're trying to make a tight turn, you want the inside wheel to "freewheel" while the outside wheel continues to drive. Oops, now the outside wheel is slipping and I need to engage the inside wheel briefly to get it moving again . . . tractor work is different from driving a Tesla down the road. There are just a lot of situations with different implements, turns/reverse operation, front tires lifted in the air, etc. that would make it difficult to program for every scenario and not have the program logic stepping all over itself. That's just my opinion on it, maybe I'm wrong. I just feel the environment for automation is much tougher in this application where you're doing so many different tasks. I do feel that there are some things that could be added to a tractor with EV-motors that aren't easily doable these days: like skid-steer mode to allow 360-spins and pivots which most tractors can't do unless it's some oddball model.

True. I mainly look at hydraulics as a way to make v1 easier to implement. Sure, you could make a front end loader with linear actuators, but it's a bunch easier to use an off the shelf hydraulic one. Same with driving front wheels, lifting attachments, etc.

I think hydraulics would still need to be reserved for lifting applications for sure, especially because that power draw would be mostly momentary high-power draw events, even if frequent, where something like spinning a PTO would generally be continuous and a much better application for a dedicated motor to minimize power losses.

It's hard enough to pioneer things like this - That's why Tesla started by just converting Lotus Elise gliders for the original Tesla Roadster, and the clean-sheet Model S was the second product. I would imagine that if Eclipse had decided to use off-the-shelf avionics and build methods instead of trying to do their own thing and get friction stir welding approved, they may have been more successful at getting their jet to market.

One advantage tractor manufacturers would have over Tesla is not needing something "road legal" to start with. I'm sure there are some general safety standards (safety interlocks) that would need to be followed, but the rest would be pretty open-design. Don't need to re-invent the wheel for implements and 3pt items since those are pretty well entrenched in industry standards.

 

[flyingcheesehead]

Again, I'm just talking about a diff lock "pedal" which allows the user to select when you need both wheels locked/engaged rather than using computer logic to guess when you want it. It need not be paired with a differential like on a standard tractor.

Oh, gotcha. Yeah, I wasn't envisioning that being a "button on a screen" kind of thing. It would still be a pedal or other physical control, it just would be implemented electronically instead of mechanically.

Ideally, barring any really good reasons to the contrary, the controls and behavior of the e-tractor would be exactly the same as those on an ICE tractor, aside from the obvious engine stuff like chokes. That's one of the things my first electrified vehicle (Ford Fusion Energi) did really well - It drove exactly like the ICE version of the Fusion, and it drove exactly the same whether the engine was running or not. If you were in D it would coast with a little bit of regen to simulate what coasting in an ICE automatic felt like, used regen for the top part of the brake pedal, and was very smooth about braking so you couldn't tell when it transitioned from regen to adding the physical brake pads. Deceleration was the same at the same pedal position regardless of how it was being accomplished. If you wanted full regen without hitting the brake pedal you shifted into L.

A tractor should be similar. If you have a conversion of an existing tractor, all of the controls should function the same and someone who gets off the ICE tractor onto the e-tractor should be able to operate it comfortably without any instruction or discomfort.

Side note: I have just decided I'm going to call internal combustion engine tractors Ice-T and electric tractors E.T.

Same reason that EVs aren't all that common in off-roading. I believe there are times when you are doing things with a tractor that are varied and the "computer logic" wouldn't be able to discern what you wanted it to do. Think traction control on a car when you're trying to get un-stuck or get up a snow-covered hill: normally it's trying to stop wheel spin, but in that situation I WANT wheelspin. So then you have to disable it. Yes, then they made "snow mode" for some cars, but even then it may not behave how you want it to. Same goes for a tractor when you're trying to make a tight turn, you want the inside wheel to "freewheel" while the outside wheel continues to drive. Oops, now the outside wheel is slipping and I need to engage the inside wheel briefly to get it moving again . . . tractor work is different from driving a Tesla down the road. There are just a lot of situations with different implements, turns/reverse operation, front tires lifted in the air, etc. that would make it difficult to program for every scenario and not have the program logic stepping all over itself. That's just my opinion on it, maybe I'm wrong. I just feel the environment for automation is much tougher in this application where you're doing so many different tasks.

While there are some opportunities to make things work better via a whole bunch of drive modes like some modern cars have, the most important thing is to do what the operator expects. Things like diff lock and limited slip can be switched on and the motors controlled to make the effect the same. As a bonus, just doing what the operator says to do makes it a lot easier to build and program.

One advantage tractor manufacturers would have over Tesla is not needing something "road legal" to start with. I'm sure there are some general safety standards (safety interlocks) that would need to be followed, but the rest would be pretty open-design. Don't need to re-invent the wheel for implements and 3pt items since those are pretty well entrenched in industry standards.

I was thinking a bit about what you could do with a clean sheet design, and one possibility that came to mind is the ability to rotate the entire operator station so that you could better see what's going on with a "rear" (3-point 540PTO) implement. There are a many cases where being able to have the implement in front of you would make it easier to operate, in the case of implements where the tractor is stationary during operation (post hole diggers, stump grinders, etc) there is no good reason to be facing the opposite direction. Or, with something like a tiller, maybe you sit sideways because you can keep a better eye on the tiller itself and then turn your head to look at the direction in which you are traveling slowly.

But, IMO, this stuff needs to come later. Step 1 should be an electrified tractor that is otherwise quite traditional in looks and function. Once you get the "electrified" part out of the way and prove its worth, then you can clean-sheet something that is a re-think based on not having the limitations of an Ice-T.

 

[StraightnLevel]

I love the idea, but I have a hard time believing that it can be practical. With ~30 acres, I would surmise that there is no current battery tech with anywhere near enough energy density to complete a day's mowing at my place....

 

[SoonerAviator]

I love the idea, but I have a hard time believing that it can be practical. With ~30 acres, I would surmise that there is no current battery tech with anywhere near enough energy density to complete a day's mowing at my place....

I agree, there's some issues depending on the application. Although, I was mainly talking about compact tractors in my initial response. Most people aren't using a 20HP tractor to cut 30 acres unless they just love doing it slowly, lol. I'd think 30 acres with a rotary cutter is going to need something in the 35HP+ range so you can at least turn a 7' implement if not even bigger tractors to run a 10'-er. Tractors in those larger sizes (Kubota L/MX-series, JD 2/3-series) are going to need too much battery draw to do the extended work times they are likely to need. Trimming up 5-10 acres with a 5' cutter might be doable on a charge.

 

[flyingcheesehead]

I love the idea, but I have a hard time believing that it can be practical. With ~30 acres, I would surmise that there is no current battery tech with anywhere near enough energy density to complete a day's mowing at my place....

What are you currently using for it? Probably bigger than I'm using but that also means more space for more batteries... And a lot of $$$.

Otherwise, the battery weight box concept would work, or some sort of fast charging. Something for this application is unlikely to happen in the next 5 years.

 

[StraightnLevel]

What are you currently using for it? Probably bigger than I'm using but that also means more space for more batteries... And a lot of $$$.

Otherwise, the battery weight box concept would work, or some sort of fast charging. Something for this application is unlikely to happen in the next 5 years.

JD X485. I can go 3-4 hours on a single tank of gas, and it covers snow-blowing duty, as well.

I don't see a technology path to batteries getting this sort of job done. The energy density just isn't there, and none of the current investigations will give the order of magnitude improvement that would be necessary to fully replace hydrocarbon fuels.

Put another way, the ICE engine isn't the environmental problem. The problem is what you put into the tank, and where it came from.

In the end, I believe that our focus has been mis-directed as a society. The energy conversion is not the problem that contributes to atmospheric carbon content. It is the SOURCE of the energy that is the problem. Burning green net-zero ethanol or methanol adds no new carbon to the atmosphere, nor does synthetic gasoline, nor bio-diesel (when processing energy is garnered from renewable sources).

Batteries are nothing more than an energy storage vehicle, and hydrocarbon fuels are no different - but hydrocarbons are FAR more energy dense and efficient over the full cycle. Address the underlying energy source so that it is something other than dead dinoasaurs, and hydrocarbons once again become the best solution for transportation over long distances or where weight is a constrained metric.

 

[flyingcheesehead]

JD X485. I can go 3-4 hours on a single tank of gas, and it covers snow-blowing duty, as well.

Wow! That must take forever... I was doing some back-of-the-napkin math the other day and figured a 60-inch deck would take a minimum of 16 hours (assuming 3 mph mowing speed). Hopefully you've got the 62" deck on it at least?

I don't see a technology path to batteries getting this sort of job done. The energy density just isn't there, and none of the current investigations will give the order of magnitude improvement that would be necessary to fully replace hydrocarbon fuels.

The technology path is to be able to swap batteries and keep going. Not that difficult.

In the end, I believe that our focus has been mis-directed as a society. The energy conversion is not the problem that contributes to atmospheric carbon content. It is the SOURCE of the energy that is the problem. Burning green net-zero ethanol or methanol adds no new carbon to the atmosphere, nor does synthetic gasoline, nor bio-diesel (when processing energy is garnered from renewable sources).

Batteries are nothing more than an energy storage vehicle, and hydrocarbon fuels are no different -

With you so far...

but hydrocarbons are FAR more energy dense and efficient over the full cycle.

And that's where you lost me. Their energy density is indeed fantastic, but obviously there are other issues to deal with; efficiency over the full cycle is debatable when you figure in the costs (monetary and energy) to extract and transport the oil, refine it into the right products, transport it again, dispense it, transport it again, and finally burn it.

Address the underlying energy source so that it is something other than dead dinoasaurs, and hydrocarbons once again become the best solution for transportation over long distances or where weight is a constrained metric.

The true underlying energy source for ALL of our energy is the sun. Petroleum products and coal are merely a way to release solar energy that was stored in them millions of years ago.

If we can create gasoline or diesel by capturing carbon from the atmosphere so that we aren't upsetting the carbon cycle by releasing all of this ancient carbon in a short time frame, great! However, if you look at the amount of energy THAT takes, it makes batteries start to look good again.

In fact, the amount of electrical power required by a refinery to create that gas or diesel is significant, even if it's coming from traditional fossil fuel sources.

But, whether or not our motivations are environmental, using electricity for our motive power gives the maximum possible versatility in energy sources. If the tractor is electric, it can be powered by solar, wind, coal, gasoline, diesel (bio or otherwise), jet fuel, geothermal, nuclear, natural gas, hydroelectric, or freaking hamster wheels... And more importantly, whatever comes next that we haven't heard of or even thought of yet.

 

[Jim Rosenow]

......and...we've come full circle! "The true underlying energy source of ALL of our energy is the sun"- flyingcheesehead.

Hence my quest to use our massive solar panel summertime over-production to mow the yard . The energy and resources needed to produce the panels are spent cost. Now the goal is to maximize gain. ;-)

Jim

 

[StraightnLevel]

Wow! That must take forever... I was doing some back-of-the-napkin math the other day and figured a 60-inch deck would take a minimum of 16 hours (assuming 3 mph mowing speed). Hopefully you've got the 62" deck on it at least?

It's faster than that. I can get everything done in a [long] day. Much of the land only gets mown a few times each year, in any case.

And that's where you lost me. Their energy density is indeed fantastic, but obviously there are other issues to deal with; efficiency over the full cycle is debatable when you figure in the costs (monetary and energy) to extract and transport the oil, refine it into the right products, transport it again, dispense it, transport it again, and finally burn it.

With all due respect, much of what you said here is irrelevant as it only applies to fossil-derived hydrocarbons - and that's why I believe that it's wrong-headed to allow it to drive our policy.

Ethanol, bio-diesel and synthetic fuels have a completely different - and far smaller - environmental footprint from fossil fuels. Europe is WAY ahead of us in developing net-zero replacement fuels, but even so we (the US) have capacity to generate more than 23 billion gallons of biofuels annually. [https://www.eia.gov/todayinenergy/detail.php?id=60281]

Meanwhile, Europe and South America are industrializing synthetic gasoline, which is a drop-in net-zero replacement fuel for every gasoline-powered car on the road today. Multiple production plants are up and running, and F1 will be using 100% net-zero gasoline from 2026 forward.

Stellantis & Aramco's eFuel Breakthrough - Green Hydrogen News

Stellantis, one of the automotive giants, has announced that 24 engine families in European vehicles sold since 2014, totaling a staggering 28 million vehicles, are now compatible with advanced drop-in eFuel.

energynews.biz

MSN

Petronor begins a green era in the Port of Bilbao with a synthetic fuel plant

Petronor inaugurates a new era of synthetic fuels in Bilbao, marking a milestone in sustainability and innovation.

bilbaohiria.com

HyCOgen FT Cans Aramco Repsol - matthey.com

matthey.com

The problem is that our governments see everything through the hyper-simplistic lens of fossil fuel powered ICEs vs. EVs powered by solar electricity. Neither view is accurate, and decisions made on that basis are inherently flawed. Yes, there is a place for EVs, but they cannot and will not solve every transportation challenge that our world presents, nor are they always the more environmentally friendly solution. The energy density just isn't there and never will be - the laws of physics and chemistry aren't going to change. However, net-zero hydrocarbon fuels are going to be more expensive than fossil-derived fuels for at least another decade, so while they will present an option we're likely to end up with transportation fuel choices driven by need for that higher energy density (long-range hauling, air transport, etc.) rather than cost.