Amount energy wasted during Regen?

[theaveng]

Over on Prius Chat some industrious owners calculated 22% of regen braking energy is wasted as battery electrical-to-chemical conversion heat. Add in heat losses from the motor and DC-AC electronics & total loss is somewhere around 30% (possibly as high as 40%).

Anyway: Has anyone ever measured regen losses in the Leaf? I would think it would be as simple as accelerating to 30, then regen braking to 0, and measuring the power flow. The difference would represent the % loss.

 

[Boourns]

This is a source of vociferous debate. Some people say it's around 50%. Others say it can't be more than 30%. There are some pretty good threads on the topic:

http://www.mynissanleaf.com/viewtopic.php?f=31&t=13584" onclick="window.open(this.href);return false;
http://www.mynissanleaf.com/viewtopic.php?f=27&t=5508" onclick="window.open(this.href);return false;
http://www.mynissanleaf.com/viewtopic.php?f=31&t=5509&start=32&hilit=drivetrain+efficiency+graph" onclick="window.open(this.href);return false;

 

[Nubo]

Go to evtv.me

In this week's show (Oct 25) there's a segment where one EV motor is used to drive another into regen and these things are measured. Remember to add charging losses for regen in a vehicle since the captured energy is being used to charge the pack.

 

[EVDRIVER]

Go to evtv.me

In this week's show (Oct 25) there's a segment where one EV motor is used to drive another into regen and these things are measured. Remember to add charging losses for regen in a vehicle since the captured energy is being used to charge the pack.

Insight from the same folks that concluded that regen was useless in an EV and then retracted it. :roll:

 

[Nubo]

Go to evtv.me

In this week's show (Oct 25) there's a segment where one EV motor is used to drive another into regen and these things are measured. Remember to add charging losses for regen in a vehicle since the captured energy is being used to charge the pack.

Insight from the same folks that concluded that regen was useless in an EV and then retracted it. :roll:

Be that as it may, they were testing real machines in the real world, and so it was a good example pertaining to the thread.

 

[johnrhansen]

kind of un

scientific but I go down a hill everyday and I get at the most 1 percent on the way down back into the battery but when I go up the hill I use 3 percent of the charge

 

[theaveng]

Nissan says about 40% is recovered and 60% of kinetic energy lost...... which makes sense since most of the energy is wasted as air friction passing over the car. If the Leaf operated in a vacuum, it could theoretically coast at 60 mph forever with very little KE loss.