# [EVDL] Using Forklift Motors



## EVDL List (Jul 27, 2007)

What's wrong with a transmission?

Sent from my iPhone



> "Bill Dennis" <[email protected]> wrote:
> 
> > I know people have used forklift motors for EVs--but are they suitable for
> > only small EVs, or could they be used on something larger? For example,
> ...


----------



## EVDL List (Jul 27, 2007)

For the purposes of my questions, let's assume that the transmission is not
available, for whatever reason.

Thanks.

Bill

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of Mike Golub
Sent: Sunday, April 08, 2012 9:30 AM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Using Forklift Motors

What's wrong with a transmission?

Sent from my iPhone



> "Bill Dennis" <[email protected]> wrote:
> 
> > I know people have used forklift motors for EVs--but are they suitable
> > for only small EVs, or could they be used on something larger? For
> ...


----------



## EVDL List (Jul 27, 2007)

Bill,

More data please:
- what is the application? Drag racer? Freeway car? NEV?
- What type of diff gearing is available? 
You can easily do the math if you take the desired speed
the wheel circumference and the diff ratio, what RPMs
that the motor will run at.
If your forklift motor is designed to run 4000 RPM and
you are lugging it below 1000 then you will have a very
unhappy motor with short (brush) life and disappoining
performance.
If you can get the diff ratio to the point that at the
max desired speed you are at or over the redline of the
motor then you might have a decent performance, if the
power from the forklift motor is adequate.
That also depends on whether there are (steep) inclines
or everything is flat where you are...

As a point of reference, I had a 5000 lbs truck
(batteries and driver included) with 50kW drive from
a 9000 RPM AC motor through a manual gearbox which was
permanently fixed into 2nd gear, so the combination of
wheel size, diff ratio and gearbox allowed the motor
to redline at 9k RPM when the truck reached its max
speed of 72 MPH.
The acceleration was not great at only 50kW but if you
can live with about 30 sec to reach Freeway speed limit
then it was a joy to drive.
The same drivetrain was also used in Prizm sedans
which would top out at 90 MPH at a much brisker accel.

For steady speed 55 MPH you need around 15kW continuous
so don't even attempt something less than 36V 500A
unless you are doing a NEV or a rock crawler with the
emphasis on crawling.

Hope this clarifies,

Cor van de Water
Chief Scientist
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water XoIP: +31877841130
Tel: +1 408 383 7626 Tel: +91 (040)23117400 x203 

-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Bill Dennis
Sent: Sunday, April 08, 2012 9:17 PM
To: 'Electric Vehicle Discussion List'
Subject: Re: [EVDL] Using Forklift Motors

For the purposes of my questions, let's assume that the transmission is
not available, for whatever reason.

Thanks.

Bill

-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Mike Golub
Sent: Sunday, April 08, 2012 9:30 AM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Using Forklift Motors

What's wrong with a transmission?

Sent from my iPhone



> "Bill Dennis" <[email protected]> wrote:
> 
> > I know people have used forklift motors for EVs--but are they suitable
> 
> ...


----------



## EVDL List (Jul 27, 2007)

Thanks, Cor. I'm thinking of a freeway capable car, not a drag racer.
Right now, I have a ford 8.8-inch differential in mind, so a variety of gear
ratios available. Probably 15-inch wheels--so somewhere in the neighborhood
of 800 rev per mile. So at a 5:1 differential ratio, about 4000 RPM on the
motor at 60 mph, and 5000 RPM at 75 mph. With a 4.3:1 ratio, about 4300 RPM
at 75 mph.

Thanks,

Bill 

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of Cor van de Water
Sent: Sunday, April 08, 2012 10:22 AM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Using Forklift Motors

Bill,

More data please:
- what is the application? Drag racer? Freeway car? NEV?
- What type of diff gearing is available? 
You can easily do the math if you take the desired speed the wheel
circumference and the diff ratio, what RPMs that the motor will run at.
If your forklift motor is designed to run 4000 RPM and you are lugging it
below 1000 then you will have a very unhappy motor with short (brush) life
and disappoining performance.
If you can get the diff ratio to the point that at the max desired speed you
are at or over the redline of the motor then you might have a decent
performance, if the power from the forklift motor is adequate.
That also depends on whether there are (steep) inclines or everything is
flat where you are...

As a point of reference, I had a 5000 lbs truck (batteries and driver
included) with 50kW drive from a 9000 RPM AC motor through a manual gearbox
which was permanently fixed into 2nd gear, so the combination of wheel size,
diff ratio and gearbox allowed the motor to redline at 9k RPM when the truck
reached its max speed of 72 MPH.
The acceleration was not great at only 50kW but if you can live with about
30 sec to reach Freeway speed limit then it was a joy to drive.
The same drivetrain was also used in Prizm sedans which would top out at 90
MPH at a much brisker accel.

For steady speed 55 MPH you need around 15kW continuous so don't even
attempt something less than 36V 500A unless you are doing a NEV or a rock
crawler with the emphasis on crawling.

Hope this clarifies,

Cor van de Water
Chief Scientist
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water XoIP: +31877841130
Tel: +1 408 383 7626 Tel: +91 (040)23117400 x203 

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of Bill Dennis
Sent: Sunday, April 08, 2012 9:17 PM
To: 'Electric Vehicle Discussion List'
Subject: Re: [EVDL] Using Forklift Motors

For the purposes of my questions, let's assume that the transmission is not
available, for whatever reason.

Thanks.

Bill

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of Mike Golub
Sent: Sunday, April 08, 2012 9:30 AM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Using Forklift Motors

What's wrong with a transmission?

Sent from my iPhone



> "Bill Dennis" <[email protected]> wrote:
> 
> > I know people have used forklift motors for EVs--but are they suitable
> 
> ...


----------



## EVDL List (Jul 27, 2007)

In a message dated 4/8/2012 10:02:12 AM US Mountain Standard Time, 
[email protected] writes: 
> I drive my S 10 pretty much every day now that I have over a 100 mile 
> range. At one point a couple years ago my useful range was only 28 miles. At 
> that point I was using a 13 inch forklift motor (36 volt) which was very 
> freeway capable. I drove (and raced) the truck 4000 miles with that motor 
> before selling it to a fellow racer.
> So after a couple mods. I have had great luck with forklift motors.
> 
> Dennis Berube



> 
> Thanks, Cor. I'm thinking of a freeway capable car, not a drag racer.
> Right now, I have a ford 8.8-inch differential in mind, so a variety of 
> gear
> ratios available. Probably 15-inch wheels--so somewhere in the 
> neighborhood
> of 800 rev per mile. So at a 5:1 differential ratio, about 4000 RPM on 
> the
> motor at 60 mph, and 5000 RPM at 75 mph. With a 4.3:1 ratio, about 4300 
> RPM
> at 75 mph.
> 
> Thanks,
> 
> Bill 
> 
> -----Original Message-----
> From: [email protected] [mailto:[email protected]] On 
> Behalf
> Of Cor van de Water
> Sent: Sunday, April 08, 2012 10:22 AM
> To: Electric Vehicle Discussion List
> Subject: Re: [EVDL] Using Forklift Motors
> 
> Bill,
> 
> More data please:
> - what is the application? Drag racer? Freeway car? NEV?
> - What type of diff gearing is available? 
> You can easily do the math if you take the desired speed the wheel
> circumference and the diff ratio, what RPMs that the motor will run at.
> If your forklift motor is designed to run 4000 RPM and you are lugging it
> below 1000 then you will have a very unhappy motor with short (brush) life
> and disappoining performance.
> If you can get the diff ratio to the point that at the max desired speed 
> you
> are at or over the redline of the motor then you might have a decent
> performance, if the power from the forklift motor is adequate.
> That also depends on whether there are (steep) inclines or everything is
> flat where you are...
> 
> As a point of reference, I had a 5000 lbs truck (batteries and driver
> included) with 50kW drive from a 9000 RPM AC motor through a manual 
> gearbox
> which was permanently fixed into 2nd gear, so the combination of wheel 
> size,
> diff ratio and gearbox allowed the motor to redline at 9k RPM when the 
> truck
> reached its max speed of 72 MPH.
> The acceleration was not great at only 50kW but if you can live with about
> 30 sec to reach Freeway speed limit then it was a joy to drive.
> The same drivetrain was also used in Prizm sedans which would top out at 
> 90
> MPH at a much brisker accel.
> 
> For steady speed 55 MPH you need around 15kW continuous so don't even
> attempt something less than 36V 500A unless you are doing a NEV or a rock
> crawler with the emphasis on crawling.
> 
> Hope this clarifies,
> 
> Cor van de Water
> Chief Scientist
> Proxim Wireless Corporation http://www.proxim.com
> Email: [email protected] Private: http://www.cvandewater.com
> Skype: cor_van_de_water XoIP: +31877841130
> Tel: +1 408 383 7626 Tel: +91 (040)23117400 x203 
> 
> -----Original Message-----
> From: [email protected] [mailto:[email protected]] On 
> Behalf
> Of Bill Dennis
> Sent: Sunday, April 08, 2012 9:17 PM
> To: 'Electric Vehicle Discussion List'
> Subject: Re: [EVDL] Using Forklift Motors
> 
> For the purposes of my questions, let's assume that the transmission is 
> not
> available, for whatever reason.
> 
> Thanks.
> 
> Bill
> 
> -----Original Message-----
> From: xx[email protected] [mailto:[email protected]] On 
> Behalf
> Of Mike Golub
> Sent: Sunday, April 08, 2012 9:30 AM
> To: Electric Vehicle Discussion List
> Subject: Re: [EVDL] Using Forklift Motors
> 
> What's wrong with a transmission?
> 
> Sent from my iPhone
> 
>


> "Bill Dennis" <[email protected]> wrote:
> >
> > >I know people have used forklift motors for EVs--but are they suitable
> >
> ...


----------

