Don Terrill’s Speed-Talk

Posted: **Wed Jul 24, 2019 7:55 pm**

Three questions on Electric Motor efficiency and regen capability.

1. What is the typical efficiency of the electric motor? You put 100kW of energy in, how much is actually moving the car? (95kW 95% ??)

2. Same question on regen. 100kW of braking, how much makes it back to the battery? (95kW 95% ??)

3. Can it absorb the same amount of energy as it puts out? Does 100kW motor have 100kW of braking ability? Or is it less or more (50kW,150kW)

Just curious

Posted: **Thu Jul 25, 2019 4:02 pm**

I don't know how much loss ,but some of the older electric cars I worked on used motor cooling for cabin heating

Posted: **Thu Jul 25, 2019 10:01 pm**

emsvitil wrote: ↑Wed Jul 24, 2019 7:55 pm Three questions on Electric Motor efficiency and regen capability.

1. What is the typical efficiency of the electric motor? You put 100kW of energy in, how much is actually moving the car? (95kW 95% ??)
https://www.engineeringtoolbox.com/elec ... d_655.html

2. Same question on regen. 100kW of braking, how much makes it back to the battery? (95kW 95% ??)
You only get to use one axle set for regeneration on a typical EV so in terms of kinetic energy recovery, it is around 55%. If you only look at kW out vs kW in, you recover around 25%. https://www.proev.com/LLPgs/LLei0005.htm

3. Can it absorb the same amount of energy as it puts out? Does 100kW motor have 100kW of braking ability? Or is it less or more (50kW,150kW)
Google is your friend.
Just curious

Posted: **Sun Aug 11, 2019 6:57 pm**

I remember seeing a drag test of a tesla where they did all the math and it ran something like mid 12's which is pretty impressive for a 100k car (

) and figured out with its regen breaking it could do that EXACT same time for about 170 runs?

Correct me if I'm wrong

Don Terrill’s Speed-Talk

Electric Motor efficiency and regen capability.

Electric Motor efficiency and regen capability.

Re: Electric Motor efficiency and regen capability.

Re: Electric Motor efficiency and regen capability.

Re: Electric Motor efficiency and regen capability.