# Brand new lift motor for $310??



## jgerig42 (1 mo ago)

Hey all - I'm super new and just googling motor options and I came across this listing






Drive Motor Dc 48v 4kw 3000rpm Dc Series Motor Zq48-4.0-c - Buy Dc Motor Kit,Brushed Motor,Golf Cart Motor 48v Product on Alibaba.com


Drive Motor Dc 48v 4kw 3000rpm Dc Series Motor Zq48-4.0-c - Buy Dc Motor Kit,Brushed Motor,Golf Cart Motor 48v Product on Alibaba.com



www.alibaba.com





Am I ignorant? Is this too good to be true? Or is this a bad option for reasons I don't yet know?


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## remy_martian (Feb 4, 2019)

Motor options for what?

4kW might work ok in a gokart, minibike, or push lawnmower.


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## jgerig42 (1 mo ago)

Yeah.. I just saw that the thing only weighs 50lbs andI've read that 100-150lbs is recommended
My bad


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## jgerig42 (1 mo ago)

Most forklift motors are 48V but when used for an EV (a light pickup in my case) you would run 72-144V through them. If you increase the voltage to increase the power, correct?
How do you calculate what the new kW or hp rating under the new voltage?


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## remy_martian (Feb 4, 2019)

Forklift motors are industrial machines, not scary edge barely making spec Chinesium knockoffs. If it's on Alibaba, it might do half the quoted spec in my opinion.

I bought some "99.9%" soft copper pipe (Chinese origin) one time...couldn't solder it because it had so much filler in it. It's a wonder they can send rockets up without the bolts breaking off.

You need to be careful about heat generation in "overclocking" a forklift in a daily driver. A fused winding or plasma-gouged commutator at a track won't get you fired for not showing up.


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## jgerig42 (1 mo ago)

Good advice


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## MattsAwesomeStuff (Aug 10, 2017)

jgerig42 said:


> How do you calculate what the new kW or hp rating under the new voltage?


You don't.

It's not a hard limit like the melting point of water or the force required to break a steel rod.

A "rating" is just someone saying "I have X amount of confidence it will survive in these fixed circumstances, for Y amount of time." If you're more paranoid or need more safety margin, or have less favorable circumstances, you'd lower your rating.

A blender motor is rated for 2hp... in blender use. Take the same motor and have it power a moped, it'll melt before your first mile trying to sustain 2hp.

You don't really know enough to re-rate anything from any calculation, so, you're just going to make some guesses.

Your guesses are based on 15+ years of people using forklift motors in EVs and seeing that they seem to hold up just fine.

Some combination of the average power draw from driving not being dissimilar from a forklift's original continuous rating, and it having large thermal mass to allow for a few seconds of higher power to accelerate, and having added airflow due to a moving vehicle, etc let you know you can do it.

General rule of thumb is that bigger is better, and you do know how big a forklift motor is, so, you can roughly guess what it's capable of by its size. It's so well established at this point you don't need to do any math, you just know if it's the right size, it's fine in a car.


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## jgerig42 (1 mo ago)

MattsAwesomeStuff said:


> You don't.
> 
> It's not a hard limit like the melting point of water or the force required to break a steel rod.
> 
> ...


This is an awesome answer! Thanks for taking the time!


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