[fredvs]

Hello everybody.


I am totally new in retrofit engine to electric.


I have a Mercedes Sprinter 313 4X4 of year 2005 and want to retrofit his engine.
So I search for all infos how to do it.


My first questions:

Can I connect the electric motor directly to the main axis or better to still use the gear box?
On the Sprinter 4X4 there is a extended gear box to switch 2X4 <> 4X4, to use low or high gear and to block differential or no.
The ideal would be to connect the electric motor to that extended gear, without the "traditional" 5 speeds gear box.
But maybe a gear box is necessary otherwise the maximum speed of the vehicle would be to low?

Or is it ok, it would reach 120 km/h with the electric motor connected without the 5 speeds gear box?

Does it exist kits for Mercedes Sprinter or must I build all from scratch?

Do you know if somebody has already done a electric retrofit of a Mercedes Sprinter?

Of course advice on what electric motor to choose, witch battery and electronic parts choose, tips, etc, are more than welcome.

Many thanks.


Fre;D

 

[Tremelune]

It is probably simpler to keep the gearbox and transfer case. The difficult part is joining the Leaf motor to the transmission. There is no kit, and the fit between output shaft and transmission must be very precise.

If you use the Leaf gearbox, you will need to build motor mounts and have custom axles made. You will probably lose 4x4. The driveshaft angles from the Leaf motor to the rear differential will need to be the same.

A highway-capable EV conversion will likely cost USD$10k in parts, depending on many things.

 

[fredvs]

Hello and many thanks for your light.

It is probably simpler to keep the gearbox and transfer case.

Ha ok, because I have seen a retrofit of a VW Van and they dont use the gear box nor the clutch.
The electric motor is directly fixed to the main drive shaft.

And it seems much easier to fix the motor to the drive shaft than to to clutch+gearbox.
But surely I miss something, and the gearbox + the clutch is needed even for a electric engine too.

The difficult part is joining the Leaf motor to the transmission.

Yes, if it not directly to the drive shaft or if it does not exist pre-build kit it would be a other adventure.
But it is doable (maybe).

A highway-capable EV conversion will likely cost USD$10k in parts, depending on many things.

Hum, ok, it is in my budget.



Fre;D

 

[brian_]

Ha ok, because I have seen a retrofit of a VW Van and they dont use the gear box nor the clutch.
The electric motor is directly fixed to the main drive shaft.

And it seems much easier to fix the motor to the drive shaft than to to clutch+gearbox.
But surely I miss something, and the gearbox + the clutch is needed even for a electric engine too.

The problem with connecting the motor directly to the driveshaft is that then the only reduction gearing between the motor and the wheels is whatever is in the final drive in the axle. That's not enough reduction, so the torque to the wheels (the motor torque multiplied by the gear ratio) will be inadequate with any reasonably sized motor. The overall gear ratio (motor speed to wheel speed) in typical EVs ranges from 7:1 to 10:1, but the Sprinter's axle will only have about 4:1, so the torque to the wheels would be about half of what it should be and you would be using only about the lower half of the motor's available speed range.

A clutch is only needed to manually shift gears in a transmission, but if you're not shifting it seems like a waste to carry around the whole transmission and use only one gear ratio.

If you want to retain 4WD (and it seems crazy to convert a Sprinter 4X4 and not use the expensive 4WD system), you need to either have two motors (for the front and the rear), or keep the transfer case (auxiliary gear box). If you keep the transfer case you could use its low range gearing, but there may be a limit on the speed at which you can use that.

If you want a high-torque and relatively low-speed motor to use without the transmission or other reduction gearbox there is the one from Chevrolet Spark EV, which was intended for use with gearing of only about 3.9:1. That's better for this purpose than a typical electric car motor, but is still small for a vehicle as heavy as a Sprinter... and I don't know in what countries the Spark EV was available.

 

[fredvs]

Hello Brian and many thanks for your answer.

The problem with connecting the motor directly to the driveshaft is that then the only reduction gearing between the motor and the wheels is whatever is in the final drive in the axle. That's not enough reduction, so the torque to the wheels (the motor torque multiplied by the gear ratio) will be inadequate with any reasonably sized motor. The overall gear ratio (motor speed to wheel speed) in typical EVs ranges from 7:1 to 10:1, but the Sprinter's axle will only have about 4:1, so the torque to the wheels would be about half of what it should be and you would be using only about the lower half of the motor's available speed range.

Aaargh, ok, I have to forget the direct-connect-to-driveshaft idea.

A clutch is only needed to manually shift gears in a transmission, but if you're not shifting it seems like a waste to carry around the whole transmission and use only one gear ratio.

Yes, it is a manual shift gears 5 speeds.

If you want to retain 4WD (and it seems crazy to convert a Sprinter 4X4 and not use the expensive 4WD system), you need to either have two motors (for the front and the rear), or keep the transfer case (auxiliary gear box). If you keep the transfer case you could use its low range gearing, but there may be a limit on the speed at which you can use that.

Of course I want to retain the 4WD external-extended feature.
But, sorry, I do not understand why 2 motors will be needed.

...there is the one from Chevrolet Spark EV,

Thanks for the note, I will take a look.

Fre;D

 

[brian_]

Of course I want to retain the 4WD external-extended feature.
But, sorry, I do not understand why 2 motors will be needed.

If I understand your plans correctly, you were talking about the possibility of connecting a motor directly to the shaft which goes to the axle. One motor can't be directly connected to two axles, so you would either need two motors (one for the front and one for the rear), or the transfer case (which has one input shaft and two output shafts). It seems that your preference is to keep the transfer case, and that makes sense.

One challenge is just terminology: in "connect the electric motor directly to the main axis", the term "main axis" is not clear, presumably resulting from a translation issue. I now realize that the intention was probably "connect the electric motor directly to the input shaft of the extended gearbox"... and at least in North America, that "extended gearbox" is normally called a "transfer case", although that's really not a good term, either.

Two separate motors would be more complicated to control, but would actually solve other problems... such as doubling the power (or drive torque) available.

To get the desired gearing, without keeping the whole 5-speed manual transmission, or using the low range of the transfer case at high speed, one possibility is to put a small single-speed or two-speed reduction gearbox between the motor and the transfer case. This is the approach taken in the F-450 electric conversion which has been discussed recently in other threads, and it is the design used in some factory conversions of trucks.

 

[fredvs]

Hello.


Sorry for the terminology, English is not my mother tongue.
Maybe with a picture it will be more easy.

You may see that there are 3 axies, 1 fixed to the gear box and 2 for transmission, one for front, one for rear.


I have to deeply study your comment but if I understood ok, you advice to use a other

small single-speed or two-speed reduction gearbox between the motor and the transfer case and not use the big 5 gear box.


One question, if I understood ok, the goal is to reduce the speed of the wheels and have a higher speed of the motor to have more power.


Or maybe it is the opposite...????


And if so, would the build in "low gear" of the 4WD box not do the job?


Thanks.


Fre.D

 

[fredvs]

This is the approach taken in the F-450 electric conversion which has been discussed recently in other threads, and it is the design used in some factory conversions of trucks.

Hum sorry for the noise but doing a search in your forum for "F-450 electric conversion"
gives... "No matching...".


Could you give the link of the topic?


Many thanks.


Fre;D

 

[brian_]

Sorry for the terminology, English is not my mother tongue.

I realize that, and I'm not complaining. We'll figure it out

Maybe with a picture it will be more easy.

You may see that there are 3 axies, 1 fixed to the gear box and 2 for transmission, one for front, one for rear.

That explains a lot!

What you have is commonly called a "divorced" transfer case, meaning that it (the transfer case, or extra gearbox) is separate from the transmission, and connected by a shaft with joints. The more common configuration is a "married" transfer case, which is attached directly to the output end of the transmission.

With this divorced setup, you can use the same kind of shaft which normally goes to an axle to connect the motor to the transfer case... but there may still be issues with that connection, since most electric motors used in vehicles are not intended to support one end of a jointed shaft. You can also use a reduction gearbox intended to connect to a common driveshaft, such as the ev-TorqueBox.

The term which I didn't originally understand is "axis"; as I later figured out, you are using that to mean "shaft".

I have to deeply study your comment but if I understood ok, you advice to use a other small single-speed or two-speed reduction gearbox between the motor and the transfer case and not use the big 5 gear box.

One question, if I understood ok, the goal is to reduce the speed of the wheels and have a higher speed of the motor to have more power.

Correct - that's the goal and using a smaller single-speed or two-speed reduction gearbox is what I was suggesting as a possibility... but using the 5-speed transmission works, too.

And if so, would the build in "low gear" of the 4WD box not do the job?

It might, but there are two likely problems:

• the lower gear of the transfer case (4WD box) may not be usable at high speed - I would check the operator's manual for the vehicle, and
• the lower gear of many transfer cases can only be used while in 4WD, but unless the transfer case has a differential in it 4WD cannot be used on a paved road, because it doesn't allow the front and rear wheels to rotate at slightly different speeds as is required in a turn.

This is very dependent on the transfer case design. Do you know the manufacturer and model of the transfer case, or do you have a link to a manual (preferably in English) for the Sprinter 4X4? We did not get the 4X4 in North America in the original version of the Sprinter.

 

[brian_]

Hum sorry for the noise but doing a search in your forum for "F-450 electric conversion"
gives... "No matching...".


Could you give the link of the topic?

This F-450 conversion has been mentioned in more than one discussion in this forum, but it is not being done by a forum member.
This is the YouTube video which shows some of the parts: https://www.youtube.com/watch?v=2v-5GB7i10o
That conversion is being done by SELOC, but their website is useless.

 

[fredvs]

I realize that, and I'm not complaining. We'll figure it out

What you have is commonly called a "divorced" transfer case, meaning that it (the transfer case, or extra gearbox) is separate from the transmission, and connected by a shaft with joints. The more common configuration is a "married" transfer case, which is attached directly to the output end of the transmission.

Ha, ok, it is about love story!
I did not know that my Van was already married!

Yes, semantic may change with language, my mother tongue is French, and, for example, a drive shaft is for us "un arbre de transmission" = "a tree of transmission"...
So many thanks for your light and I will study the ev-TorqueBox.

.

• the lower gear of the transfer case (4WD box) may not be usable at high speed - I would check the operator's manual for the vehicle, and
• the lower gear of many transfer cases can only be used while in 4WD, but unless the transfer case has a differential in it 4WD cannot be used on a paved road, because it doesn't allow the front and rear wheels to rotate at slightly different speeds as is required in a turn.

With the Mercedes Sprinter transfer case (4WD box), you may choose:

- Set to 2x4 (only rear transmission) or 4x4 (rear + front transmission) and this if you have set low or high gear.
- Block or not the differential. Of course if the differential is blocked, it is easy to turn only on sandy road.

Many, many thanks for your explanation, I will check all this, write you later.

Fre;D