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Discussion Starter · #1 · (Edited)
Hi!

Im trying to acquire as much information as I can before undertaking My electric car conversion, and what I value above any other parameters Is acceleration for this project. Ideally, it would be between 3-4 seconds to get from 0-60 Mph.

How important is a motor in terms of acceleration? If I can supply high current and voltage up to my desired top speed, Are most forklift drive motors going to give me similar acceleration when compared to something like a Warp-9, or other 'high end" EV conversion motor?

For acceleration, If my motor isn't able to get up to 4k RPM but can generate significant torque, Will it still be able to get to good top speeds? (given sufficient current to maintain torque) As far as I know, in ICE cars most motors never go to such high RPMs but can still go fast, but I might be wrong.

Is the most critical component for EV acceleration the battery/supplying power?

Basically, my question is if all of my components were good but not excellent, What would generally be the best thing to upgrade to be able to accelerate faster?

Thanks!
 

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For acceleration, If my motor isn't able to get up to 4k RPM but can generate significant torque, Will it still be able to get to good top speeds? (given sufficient current to maintain torque) As far as I know, in ICE cars most motors never go to such high RPMs but can still go fast, but I might be wrong.
Engines are generally kept at the lowest speed at which they are capable of producing the power required of them, because that it best for efficiency, wear, and noise. Since most of the time a car is not accelerating very hard compared to what it can do (because the accelerator pedal is not pushed to the floor), most of the time the engine in a car is running slowly, relative to the high speed at which it can produce maximum power. In normal driving, most car engines probably don't exceed 4,000 RPM on most drives , except during brief spurts of acceleration, simply because they don't need to.

In general, bigger engines are limited to lower speeds than smaller ones, and diesel engines are limited to lower speeds than gasoline engines of the same size, but there is lots of variation due to specific application and design considerations. There probably isn't an engine (of any size or type) in any car which can't handle at least 4,000 RPM and most need to run substantially faster than that to produce their maximum rated power.

Similarly, larger electric motors are limited to lower speeds than smaller motors, and different types of motors have different speed capabilities (brushed DC motors cannot handle the high speed that a similarly sized brushless AC motor can)... but again, those are only general trends rather than anything that could be blindly applied to a specific motor.
 

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Every component which handles the power used to drive the car must be adequate for the job. That means the battery, controller, motor, transmission, and axles... but not (for instance) the charger or DC-to-DC converter.

You can use the biggest battery ever put in an EV but if you only have a little motor suitable for a scooter, you will only either have poor performance or you'll blow up the motor. You can use the most powerful motor ever put in an EV but if have only small battery you'll destroy the battery trying to run the motor to its full capability. You can have a whole EV supercar battery and motor, but if the controller connecting them can only handle the power of a golf cart you'll have to settle for performance like a golf cart, or blow up the controller.

As with almost any aspect of life and technology, the key is balance. Each component has a capability; you can choose which one you want to push harder than it is supposed to be, if you can accept the resulting loss of lifespan and reliability, but whatever you choose there will be consequences.

A typical DIY EV approach using old brushed DC motors is to push the motor far harder than it was ever intended, on the basis that full power is only needed for a few seconds at a time so the motor will survive long enough, to push the battery a bit harder than was intended because it will work well enough, and to operate the controller within its rated limits because there's no way to avoid those limits (of voltage, current, and power). But you pick the balance, and the specific components which you choose will determine how much you can get away with.
 
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