[Northern448]

Just wanted to update the limited progress over the past few weeks. For the cabling between the battery bank and motor controller I purchased some Anderson power product connector components online (terminals, housings, and weatherproof casing) and picked up some 1/0 awg welding cable locally. The three cable assemblies I needed to make were battery bank to tractor (source), front of tractor to motor controller (load), and rear of tractor to motor controller (load). I used the SB series Anderson connectors (175A version).

Push wires through weatherproof casing and crimp terminals:

Put terminals into housing:

Push housing into weatherproof casing:

I used glue walled heat shrink for a better seal and visual indication of +/- leads:

The idea being if the battery box is connected at the back, the front connector can be capped off and vice versa. I'm working on some brackets to secure these connectors to the front and rear of tractor.

 

[Northern448]

Just some finishing up of the body work while I wait on parts for the charging system. Finally got the decals on!

 

[Harry]

Northern448, I think your paint scheme with the orange and black colors! Interesting build your in the process of creating! Good luck!

Keep the Peace
Harry

 

[67halfcab]

It will be interesting to see how bad the parasitic losses will be by using the electric motor to drive the hydraulic drive system vs a direct drive electric system. Circulating fluid with the pump while not moving (idling) would be my concern with losses.

while idling, other than for cooling the oil, why would you need to keep circulating the oil? Hydrostatic units stop flow when idle so I don’t see much need to keep it moving other than a little cooling. I would see this as a bonus for ev, the hydraulic pump isn’t generating more heat (unnecessarily) while sitting idle and your parasitic loss would be zero.

 

[a66coup289]

while idling, other than for cooling the oil, why would you need to keep circulating the oil? Hydrostatic units stop flow when idle so I don’t see much need to keep it moving other than a little cooling. I would see this as a bonus for ev, the hydraulic pump isn’t generating more heat (unnecessarily) while sitting idle and your parasitic loss would be zero.

The drive system on our tractors is hydraulic, NOT hydrostatic. In our systems the pump circulates a fixed amount of fluid on each revolution. Fluid does not stop, but is only re-directed via the valves. As such, any energy needed for the pump to idle and push fluid through any non-drive circuit is what I am considering parasitic. As long as the motor is spinning, the pump is spinning and thus losses exist.

A good description of the difference between the two systems can be found here:

Hydrostatic vs Hydraulic drive? Re... - Yesterday's Tractors

In reference to the Case 222 post below. What is the difference between the two types of drive? I thought they were the same thing?

www.yesterdaystractors.com

Even with a hydrostatic system the charge pump is always moving some oil for cooling, thus some loss. For that matter, spinning the fan to move air over the cooling radiator consumes energy.

 

[Jancoe]

Seems someone did this to a case already. Not much info in the article but figured I'd share what I found.

Electric Riding Mower Conversion – Mother Earth News

With a little work and some parts from a salvage yard, learn electric riding mower conversion from a used lawn tractor to run on electricity.

www.motherearthnews.com

Sent from my SM-G975U using Tapatalk

 

[67halfcab]

The drive system on our tractors is hydraulic, NOT hydrostatic. In our systems the pump circulates a fixed amount of fluid on each revolution. Fluid does not stop, but is only re-directed via the valves. As such, any energy needed for the pump to idle and push fluid through any non-drive circuit is what I am considering parasitic. As long as the motor is spinning, the pump is spinning and thus losses exist.

A good description of the difference between the two systems can be found here:

Hydrostatic vs Hydraulic drive? Re... - Yesterday's Tractors

In reference to the Case 222 post below. What is the difference between the two types of drive? I thought they were the same thing?

www.yesterdaystractors.com

Even with a hydrostatic system the charge pump is always moving some oil for cooling, thus some loss. For that matter, spinning the fan to move air over the cooling radiator consumes energy.

I understand ours tractors are hydraulic and not hydrostatic and since we have gas engines running all the time, fluid never stops. But in an electric setup you have better control so lower the motor speed or stop it when not needed. Your loss would be minimal at best. I still see this as a win for efficiency. Even running a small fan on the radiator would be minimal.

 

[a66coup289]

I understand ours tractors are hydraulic and not hydrostatic and since we have gas engines running all the time, fluid never stops. But in an electric setup you have better control so lower the motor speed or stop it when not needed. Your loss would be minimal at best. I still see this as a win for efficiency. Even running a small fan on the radiator would be minimal.

Based on the above it would be far more efficient to simply ditch the hydraulics and go direct drive electric. Under the above scenario one would need to throttle the electric motor to reduce flow in the system but that would be no less cumbersome than working the throttle to "hypermile" a gasoline engine while still controlling motion with the hydraulic valve. A 7 1/2" electric cooling fan draws about 5.5 amps at 12v. That's somewhere between 2 - 2.5% of the OP's storage capacity.

Don't get me wrong, I think it's a cool project I just wonder how much will be lost using the standard hydraulic drive system. One will see losses in:

1.) The pump
2.) Friction losses of fluid through the lines and valves
3.) Drive motor
4.) Gears in transaxle
5.) Cooling fan

Yes, all those losses exist with the factory ICE, but they would not exist with a direct drive electric motor.

 

[dundee222]

You still need reduction gears in the transaxle, but everything else is a loss. Although getting enough reduction in the trans for an electric drive motor might prove a challenge.

 

[a66coup289]

You still need reduction gears in the transaxle, but everything else is a loss. Although getting enough reduction in the trans for an electric drive motor might prove a challenge.

DC motors have lots of torque, that's why electric cars are so quick. I would expect them to need LESS gear reduction than an ICE. I could be wrong.

 

[dundee222]

Dc motors have gobs of torque but not compared to the hydraulic motor on a Case transaxle. Would take a very large electric motor to replicate the low end torque of the present drive motor. My buggy has 12 to 1 reduction behind an aftermarket torque motor and that is with 22" tall tires, and while good, still won't pull like my 446, at least continuously.

 

[a66coup289]

Dc motors have gobs of torque but not compared to the hydraulic motor on a Case transaxle. Would take a very large electric motor to replicate the low end torque of the present drive motor. My buggy has 12 to 1 reduction behind an aftermarket torque motor and that is with 22" tall tires, and while good, still won't pull like my 446, at least continuously.

Gotcha. I just looked at the torque specs of the OP's motor and that of a K321 - similar, and not that much. Only 22+/- ft*lbs. Certainly lots of gear reduction needed.

 

[dundee222]

Sorry, I was meaning if one was to use an electric motor directly on the axle in place of the hydraulic one. But you do raise a concern I had too about the motor being used running the pump, but the Kohler had to run the pump AND power the deck or caster off the other end at the same time. Just for reference, my buggy in 6" deep snow this morning was pulling over 200 amps continuously and took 300 at times at 48 volts.

 

[Northern448]

I did give some thought to this at the start of the project; direct drive vs utilizing the existing hydraulic system. There are benefits to a direct setup, including, as you mentioned, reduced system loss. Also a direct drive system would have allowed me to use regenerative braking, improved throttle control, and simplified forward / reverse.

However, in the end the benefits to utilizing the existing hydraulic system won out for me personally; replacing the internal combustion engine with an electric motor is less invasive to the overall design than the required modifications to convert to direct drive. The other factor was maintaining the hydraulic PTO for use with the hydraulic tiller.

I’m working on ways to maximize battery runtime including turning off the motor when stationary and implementing a “smart” hydraulic cooling fan (turns on based on temperature). However, with the system voltage being 48Vdc the 17W cooling fan draws less than an amp. But het, this is a learn as you go project…

 

[Northern448]

Oh and I forgot to mention if you're missing the cap on the steering wheel, nothing beats the cap off a good can of Wilson's one shot...

 

[Woody184]

Just getting ready to paint my Case 224 would you share the exact orange color. Love it. Also are the tires Hi-run. Haven’t mounted mine, looking good

 

[wendell]

It seems to me that you could spin down the electric motor when pressure is not needed. This ignores cooling, so you'd have to experiment with that. As I read it, the page in the link below indicates that this can be done by placing pressure switches on the high side and low side of the pump, and comparing their output. You'd vary the motor speed to keep those pressures as close as possible.

StackPath

 

[Northern448]

Just getting ready to paint my Case 224 would you share the exact orange color. Love it. Also are the tires Hi-run. Haven’t mounted mine, looking good

The paint is Dupli-Color DE1607 engine enamel (chevy orange-red), another member recommended this and here in Canada it's available at Canadian Tire...

Rear tires with: BKT model: TR144 and the front tires with Carlisle Super Lug model: 5100969

 

[Northern448]

It seems to me that you could spin down the electric motor when pressure is not needed. This ignores cooling, so you'd have to experiment with that. As I read it, the page in the link below indicates that this can be done by placing pressure switches on the high side and low side of the pump, and comparing their output. You'd vary the motor speed to keep those pressures as close as possible.

StackPath

Makes sense however in this particuar application I want to maintain a constant RPM, you don't want the drive speed to slow down if you shut off the PTO attachment. That's the idea behide the temperature based fan control.

 

[dundee222]

Your oil cooler fan draw is negligible. Even if you forgot it on for a day or 2, it isn't going to affect runtime. If you were basing runtime on mileage, you would need a tape measure to see the difference. LOL