Motor power

Do It Yourself (DIY)
1

Many conversions I’ve read about talk about how fewer gears are needed with an EV motor – often just two.

But,

electric motors are most efficient at the upper end of their speed rating. If you run an electric motor at the same speed as you do your gas engine its hp and efficiency are going to suck as well as pull a lot of amps.

Could a less powerful motor, one that might require more gears, still effectively power the EV, or is the gearing thing not related to motor power in the way I’m thinking?

EDIT: Granted, an EV motor running from 1,000 to 5,000 rpms would fall into the “same speed as you do your gas engine” category. What if the EV motor output was altered via a fixed gear ratio before it reached the transmission, so that the operating range of the manual transmission were more in line with the efficient range of the EV motor?

What I’m getting at is this: Is there any benefit to building a set-up that would go through 1st through 5th gear – could the motor be smaller, thereby saving on the amp requirement?

2

You’re still going to need power to keep you at speed and help you up the hills. Sure you could use a smaller motor but you may end up crawling around with everyone swearing at you as they blow by. If you use a small motor and overwork it you’ll pull more amperage than it is rated for and it will heat up and eventually the insulation will melt. Then you’ll need a new motor along with all the parts that fried when your motor shorted out.

To maximize motor efficiency use the gear that allows you to spin the motor at it’s most efficient RPM. Electric motors have balls of torque from a dead stop which is why you don’t need many gears. You will pull less amps if you run through all your gears but it’ll be slower off the line than a 2nd gear or 3rd gear start. Sometimes it’s all about smoking the dude in the Camaro off the light.

3

If you use a small motor and overwork it you’ll pull more amperage than it is rated for and it will heat up and eventually the insulation will melt. Then you’ll need a new motor along with all the parts that fried when your motor shorted out.

Point well taken.

Sometimes it’s all about smoking the dude in the Camaro off the light.

Doesn’t do me much good if I run out of juice in mid-commute

4

Just do it at lunch time when you can go back to the office and plug it in, or do it on a Sunday on the way to church.

5

Lunch time works, but the Camaro boys are still sleeping off Saturday night at church time… :wink:

6

More power means you can go faster, but I would think that having more gears would help save your battery at lower speeds.