#### motomoto

##### 1 kW

- Joined
- Jun 28, 2010

- Messages
- 458

getting every ounce of acceleration out of their bikes. I mean, they are in the area of the power band that

makes the most horsepower. Which means they are in the proper gear for the speed they are traveling.

On ES we have a lot of 'Gurus' informing us that a gearbox is never needed, and all that extra useless weight

should be used for magnets and copper and battery.

So I want to look at 2 different aspects of this scenario. One is fastest possible acceleration and the other

is efficiency.

First efficiency. I will use arbitrary numbers. Lets say you have a motor that makes the most horsepower

at 8,000 rpm. It will rev more but the torque is dropping. The highest area on the horsepower curve is

between 6,000 and 9,000 rpm. I am going to leave voltage out of this example and look at amperage

because amperage produces torque and torque times rpm equals horsepower. To make this example

simple, lets say that at 100 amps the motor makes 10 horsepower at 1,000 rpm. At 2,000 rpm it make

20 horsepower and so on until the torque starts to drop off. For my 100 amps I want to be efficient,

so why would I run the motor at any rpm other than 6,000 to 9,000? At 1,000 rpm you are only getting

10 hp. At 8,000 you are getting 80 hp for your 100 amps.

Now on to power. Accelerating in high gear is slow. Torque from an electric motor is tremendous. High

numbers all the way across the graph. Terrific. But come on, not having it in the right rev range, so much

for your acceleration and lap times.

All the 'gurus' will say you just have to have this huge motor in your vehicle that breaks the tire loose at any rpm.

Well that is great, but then you've got the waste of amps thing going and not getting the most horsepower for the amps

you are putting into the motor. To me throwing a bunch of amps at a low rpm is a waste and is slow even though it

feels 'torquey'