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Discussion Starter · #1 · (Edited)
I have a Chins 4x4 UTV that I want to convert to EV. The motor is removed and I have easy access to the Front and Rear Driveshafts. Unfortunately, the transmission is/was part of the engine housing, and all that is gone.

So My option is to find a way to mount one engine to a transaxle that will drive both drive shafts (to allow me access to 4x4 mode), or just remove the front driveshaft and connect to the rear shaft.

Assuming I take the easy route, what is the suggested motor and controller for a 1100lbs unit (dry curb weight), 1400lbs loaded with people. knowing the following:
Max speed we need 15mph
Runtime < 30 minutes
Prefer Lots of Torque over speed

I can make the battery pack (I will use LifePo4 cells) so doesn't matter what motor or control voltage I need.

The splines are as follows:
Front Drive Shaft (see closeup image attached)
The end that slides into the Front Differential has a diameter of 19.5mm (peak of the splines) and it has 19 teeth. The smallest diameter (as measured at the valley of the splines) is 17.5mm (+/- .5mm)
The length of the spline before it hits the snap is 20mm After the snap ring (hidden by the rubber boot) the splines continue another 10mm. The splines themselves appear to be 1mm high

The end of the drive shaft where the drive train will be (i.e. motor or transmission/motor, etc..) the spline portion of the shaft is 25mm long, 19.25mm in diameter, has 19 teeth and the smallest diameter is 17.5mm making the splines themselves 1mm high



Rear Drive Shaft
The end that slides into the Rear Differential has a diameter of 34.5mm (peak of the splines) and it has 26 teeth. The smallest diameter (as measured at the valley of the splines) is 31.5mm (+/- .5mm)
The length of the spline portion of the shaft is 23mm long, The splines themselves appear to be 1.5mm high

The end of the drive shaft where the drive train will be (i.e. motor or transmission/motor, etc..) the length of the spline portion of the shaft is 18mm long, 41.5mm in diameter,has 25 teeth and the smallest diameter of the shaft is 34.5mm making the splines themselves 3.5mm high

Example of the UTV
Tire Wheel Vehicle Car Automotive tire


View of Chassis:
Wheel Tire Automotive tire Motor vehicle Tread
 

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I have a Chins 4x4 UTV that I want to convert to EV. The motor is removed and I have easy access to the Front and Rear Driveshafts. Unfortunately, the transmission is/was part of the engine housing, and all that is gone.

So My option is to find a way to mount one engine to a transaxle that will drive both drive shafts (to allow me access to 4x4 mode), or just remove the front driveshaft and connect to the rear shaft.
You missed the obvious other option, which is to drive the shaft to the front with one motor, and the shaft to the rear with another motor.

Also, while this UTV apparently had everything integrated, I'm pretty sure that there are other UTVs/ATVs that have a separate transfer case to take one transmission output and connect it to both front and rear, probably with a way to disconnect the front when it is not needed - it's likely possible to adapt one of those.
 

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I guess a lot of these decisions would depend on the range of uses that this thing would do. If you are considering abandoning 4WD, is it something you really wouldn't need often enough to justify keeping it?
What level of fabrication and machining are you comfortable with? Do you have reliable resources for that?
Any idea of the axle gear ratios and input directions of the 2 driveshafts?

drive the shaft to the front with one motor, and the shaft to the rear with another motor.
At first thought this may add cost and complexity with (possibly) the extra controller, etc, but it could be an asset for getting home out of the bush if the other axle drive failed. It would keep driveshaft adaptation on the easier side. Might also be a range saver option if you could switch one OFF at flat road cruising.

Also, while this UTV apparently had everything integrated, I'm pretty sure that there are other UTVs/ATVs that have a separate transfer case to take one transmission output and connect it to both front and rear, probably with a way to disconnect the front when it is not needed - it's likely possible to adapt one of those.
If you could find a standalone transfer cases with sealed input and output hubs/shafts this would be the way to go. I am assuming that the quality of the old t-case was not very high after seeing some cratered plastic internals of modern UTV parts a few weeks ago. If you trust the rest of the drivetrain to take higher torque, maybe you could choose a larger t-case to allow for the higher torque levels the EV motor may deliver.

Another option I will throw in to be critiqued : Small IRS differential (possibly LSD if required) as the transfer case with the motor on top/ behind/whatever, using a beefy timing belt (or 2 or 3 normal sized). Pick a common cog sizing and you have a lifetime supply of scrapyard pulleys of different sizes to tune or change your motor:drive ratio as desired.

Also with a UTV with a low daily "yard" range requirement, you could keep the onboard battery small to start and build a utility trailer with a battery floor for range extension later on.

Good luck!
 

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Discussion Starter · #6 ·
You missed the obvious other option, which is to drive the shaft to the front with one motor, and the shaft to the rear with another motor.

Also, while this UTV apparently had everything integrated, I'm pretty sure that there are other UTVs/ATVs that have a separate transfer case to take one transmission output and connect it to both front and rear, probably with a way to disconnect the front when it is not needed - it's likely possible to adapt one of those.
I thought about that, wasn't sure how that would be possible to sync the two so that one is not fighting the other. I have the ability to disable the front differential via a solenoid.
 

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Discussion Starter · #7 ·
You missed the obvious other option, which is to drive the shaft to the front with one motor, and the shaft to the rear with another motor.

Also, while this UTV apparently had everything integrated, I'm pretty sure that there are other UTVs/ATVs that have a separate transfer case to take one transmission output and connect it to both front and rear, probably with a way to disconnect the front when it is not needed - it's likely possible to adapt one of those.
If there are, I haven't found it =o)
 

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Discussion Starter · #8 ·
I guess a lot of these decisions would depend on the range of uses that this thing would do. If you are considering abandoning 4WD, is it something you really wouldn't need often enough to justify keeping it?
What level of fabrication and machining are you comfortable with? Do you have reliable resources for that?
Any idea of the axle gear ratios and input directions of the 2 driveshafts?
I can calculate the gear ratio, sure. I am sure I can get most parts off the shelf, the bigger challenge is going to be motor couplers to the bizarre spline I see on the front and rear drive shaft.

At first thought this may add cost and complexity with (possibly) the extra controller, etc, but it could be an asset for getting home out of the bush if the other axle drive failed. It would keep driveshaft adaptation on the easier side. Might also be a range saver option if you could switch one OFF at flat road cruising.
Correct, and I can easily disengage the front differential via a switch.


If you could find a standalone transfer cases with sealed input and output hubs/shafts this would be the way to go. I am assuming that the quality of the old t-case was not very high after seeing some cratered plastic internals of modern UTV parts a few weeks ago. If you trust the rest of the drivetrain to take higher torque, maybe you could choose a larger t-case to allow for the higher torque levels the EV motor may deliver.
Correct, no luck going that direction. I at this point was just focused on a direct motor connection to the rear drive shaft. Need high torque low speed. Its for pulling a seed spreader nothing else.

Another option I will throw in to be critiqued : Small IRS differential (possibly LSD if required) as the transfer case with the motor on top/ behind/whatever, using a beefy timing belt (or 2 or 3 normal sized). Pick a common cog sizing and you have a lifetime supply of scrapyard pulleys of different sizes to tune or change your motor:drive ratio as desired.
So no way to couple the motor direct and have the motor controller manage the torque/speed?

Also with a UTV with a low daily "yard" range requirement, you could keep the onboard battery small to start and build a utility trailer with a battery floor for range extension later on.

Good luck!
 

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Discussion Starter · #10 ·
You missed the obvious other option, which is to drive the shaft to the front with one motor, and the shaft to the rear with another motor.

Also, while this UTV apparently had everything integrated, I'm pretty sure that there are other UTVs/ATVs that have a separate transfer case to take one transmission output and connect it to both front and rear, probably with a way to disconnect the front when it is not needed - it's likely possible to adapt one of those.

Basically its this beast I am converting to EV
Tire Wheel Vehicle Car Automotive tire


Project Type: Chins 700 4x4
No Load Weight: 1100 lbs.
Full Load Weight: 1500 lbs.
Drive Wheel Diameter: 12 in.
Rolling Tire Radius: 6 in.
Quantity Per Year: 10 or less
Comments: Converting this from ICE to Electric. Need motor, controller and pedal. Click here to see project Pictures

Mechanical Design
Output Shaft Type: Splined
Splined A: 41.5mm
Splined B: 34.5mm
Splined C: 18mm
Splined Teeth: 26
Differential/Transmission & Axle Gear Ratio: no transmission
Differential/Transmission & Axle Efficiancy:
Comments:
The motor will drive the rear driveshaft which is directly coupled to the rear differential unit.


Performance Requirements
H.P. Required: apx 35
RPM Required: unknown
Maximum No Load Speed: 15 MPH
Maximum Full Load Speed: 15 MPH
Minimum Vehicle Speed Up 5 % Grade: 10 MPH
Comments: I will build the battery pack once we know what you need from you motor and controller wise

Electrical Requirements
Controller Type:
Volts:
48 volts
Maximum Current: 600 Amps
Battery Type: LifePo4
Battery Amp Hours: 205
Duty Cycle: 50%
Vehicle Range: 1 hour per day
Comments: Can be anything here, need to get your thoughts on motor and controller
 

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I thought about that, wasn't sure how that would be possible to sync the two so that one is not fighting the other. I have the ability to disable the front differential via a solenoid.
They don't have to fight because they don't need to run at the same speed. At the simplest level, you can feed the same accelerator pedal to both motor controllers.
 

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"So no way to couple the motor direct and have the motor controller manage the torque/speed?"

I'm not necessarily saying there is no way to do that, but you will need to find a motor that matches closely enough to the torque needed taking off from a stop (with trailer load), as well as its best efficiency at normal seed spreading speed. Sometimes finding the cheaper and readily available motor and adapting your gearing to suit the previous requirements is "easier" in the long run if you run into unexpected performance issues...
Still, a motor direct to the rear driveshaft is your easiest way forward if you can nail the motor specs.
 

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The timing belt trick could still work for attaching to rear differential. Run the driveshaft into a bearing and put a pulley on the end.
Not the simplest option off the bat, but just throwing around ideas.

In regards to motor/controller choice, doesn't sound like you will need regen, DC motor should likely cover your needs and probably cheapest.
 

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Discussion Starter · #15 ·
They don't have to fight because they don't need to run at the same speed. At the simplest level, you can feed the same accelerator pedal to both motor controllers.
I ran across this on Aliexpress, wonder if that's a viable option?



Expensive but looks like it has all the parts I need ? Appears to have a transmission, pedal, controller, etc.. only real challenge then is mating up the drive shafts to the front and rear differential
 

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Discussion Starter · #16 ·
The timing belt trick could still work for attaching to rear differential. Put the driveshaft into a bearing and put a pulley on the end.
Not the simplest option off the bat, but just throwing around ideas.

In regards to motor/controller choice, doesn't sound like you will need regen, DC motor should likely cover your needs and probably cheapest.
Thanks, that's what I am not sure of... do I need a DC motor for this weight/torque or am I better off with an AC Motor?
 

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My experience with DC is having more torque from 0RPM than comparible AC size.

Edit/addition:
...but with only 15mph top speed, AC may still do the trick with correct gearing. I will keep emphasizing that point.
 

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Discussion Starter · #20 ·
He never said that.

You're looking for a free lunch and Mother Nature doesn't even make sandwiches for you.
I'm not trying to say anything. Trying to learn from those who know. I haven't mentioned anything about budget, etc..

My advice is quit trying to play chef on your comments if you have nothing related to the topic to discuss.
 
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