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Discussion Starter · #1 ·
Hi,


I have 72/80V 12" forklift drivemotor for my first EV project. Thinking that i run 96V ? Which is suitable and deasent prize controller?


I can also buy one off them if here is for sale? Needs to be shipping...


Thanks
Jani
 

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Hi Jani

You will need at least 150v to get useful performance in a car

In the forklift full speed will be about 1400 rpm - going up to 96 volts may get you up to 2000 rpm
Not enough in a car
 

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Discussion Starter · #3 ·
Hi,


I have gearbox...and iam going to take easy start. Just getting my staff works...


Maybe later think about top speeds and other...


There is many controllers, thats why aim asking...


Thanks.
 

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Hi Jani

You will need at least 150v to get useful performance in a car

In the forklift full speed will be about 1400 rpm - going up to 96 volts may get you up to 2000 rpm
Not enough in a car

Being a 12" motor I might have to agree with you but I did a VW Ghia Conversion with a 9" GE motor and 96 volts and it would do nearly 80 mph. Not what I would call blazing acceleration to that speed but it would do up to 65 mph like any decent vehicle and did pretty darn good up to about 45. I used my stock transmission and I did shift. My only complaint was range and those heavy lead acid batteries.
 

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Hi OneGreenEV

It was the voltage in the forklift that worried me - if it was using 72v to produce power at (guess) 1400 rpm - then 96v would only be a couple more rpm

Your 9 inch motor would be using 36v? to produce power at 1400 rpm - so your 96 volts would be producing the same torque at - 3700 rpm ??
 

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Hi OneGreenEV

It was the voltage in the forklift that worried me - if it was using 72v to produce power at (guess) 1400 rpm - then 96v would only be a couple more rpm

Your 9 inch motor would be using 36v? to produce power at 1400 rpm - so your 96 volts would be producing the same torque at - 3700 rpm ??
Ahh! Thanks for the education. Love learning new things. Makes perfect sense.
 

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Discussion Starter · #7 · (Edited)
So if i had 48V allmost same size motor it would be better with 96V? Even 48V motor has less torgue...when you look motor ínformation plate?


Jani
 

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I have a 48 volt motor
When I used it with 144 volts it was good

I did a bit of battery re-arrangement and ended up with more batteries but only 130 volts

With 130 volts I was voltage limited to 100 kph - it would take off like a scalded rat and then simply stop accelerating

They put me next to a Ferrari on a drag strip - I beat it off the line
Then it went howling past me - I stopped accelerating after about 200 meters

I'm now using 340 volts - but most people do think that is a wee bit extreme

96 volts is a bit too low for a car

The issue is the gear ratio - in most cars top gear is about 4:1 overall - so with normal car type wheels you need about 4000 rpm
 

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Discussion Starter · #9 ·
I can change my motor if i like 72/80V to 48V...Should i do that?


Is there major different if 72/80 V motor type plate has RATING: 60 min
and 48V motor have RATING: 5 min


72/80V has 10.6Kw and 48V has 10Kw


Thanks!
 

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I can change my motor if i like 72/80V to 48V...Should i do that?


Is there major different if 72/80 V motor type plate has RATING: 60 min
and 48V motor have RATING: 5 min


72/80V has 10.6Kw and 48V has 10Kw


Thanks!
OK the 48 volt motor is only rated for 5 minutes the other is one hour rated

To be quite honest neither is that good for a car

The 48v one will be easy to get to the right rpm and will work with about 144 volts
BUT it's not rated very high and will probably overheat

The 72 volt one will not overheat BUT you will probably need a much higher voltage - 200 volts??

You need to post lots of pictures of both motors for people to have a look at

You need the overall size, pictures of the brushes and the commutator and pictures of the drive end - both ends would be best

And pictures of the labels
 

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Just four brushes - NOT a good sign

I would put that to one side and keep looking - it may be usable but you should be able to find something better
 

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Discussion Starter · #15 ·
Is there forklifs brand and model, where is suitable motor?

And if i found 48v rating 60 min motor, is it ok? Even four brushes?
 

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Is there forklifs brand and model, where is suitable motor?

And if i found 48v rating 60 min motor, is it ok? Even four brushes?
Hi
You are looking for a much longer commutator with four PAIRS of brushes

I have a Hitachi forklift motor - they seem to be the most common here
 

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And if i found 48v rating 60 min motor, is it ok? Even four brushes?
The voltage matters less than the power (kilowatts).

An industrial motor will be rated for minimal airflow since they're normally running indoors buried in machines, so a motor with a 60min rating of 11kw might be able to put out 15-20kw for an hour with appropriate cooling, but the duty cycle for cars normally looks like accelerating for 30 seconds, then several minutes of cruising. This means the motors might be able to handle 40kw for short sprints, whereas cruising at 70mph/110kmh in a relatively aerodynamic modern car should only need 15kw.
 

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Discussion Starter · #19 ·
Hi again...


If i keep motor that i have now...


Is there any calculation metod or good quesses that how much more rpms motor will take 120V?
 

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Hi again...


If i keep motor that i have now...


Is there any calculation metod or good quesses that how much more rpms motor will take 120V?
The motor - in the forklift - will be able to draw full power
So at 1400 rpm and 80v it will produce 10 kW - that is about 125 amps

Now we come to the guesswork
Lets estimate that the motor will produce 60 volts of "Back EMF"

So it's about linear so spinning up to 4200 rpm at the same current will produce three times the back EMF - 180 v - so you will need 200 v to run up to that sort of speed
 
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