How much power is actually regenerated coasting or going downhill?

[VoltSoundz]

Does anyone know how much power is regenerated coasting or going downhill? I think the digital readout inside the car is misleading, because when you are driving up a hill, your remaining miles start disappearing very fast.. because I think the computer is trying to calculate how many more miles you could drive if you kept going uphill the whole way. But then when you start cruising downhill, you get many of those miles back... but how many are from regeneration and how many are from the computer correcting itself now that it knows you will not be driving 30 miles uphill! Anyone have stats?

Once I drove uphill for 10 miles. The car said it used 20 miles worth of charge. When I cruised back down the same hill, I got 10 of those miles back, plus the 10 downhill miles used nothing. So in the end it appears that I went 20 miles on 10 miles worth of charge.

Thoughts?

[DonC]

Regen on the Volt is 30%-35% efficient. Freewheeling is 100% efficient.

[yoyodyn]

I had a similar question for someone. How much of an incline would be required for the Volt to maintain to increase speed using just the "L" gear and no brake pedal? And also, how much energy would that give you per mile?

[petefoss]

Regen on the Volt is 30%-35% efficient. Freewheeling is 100% efficient.

Got a reference for that 30-35% estimate?

[AndrewW]

Regen on the Volt is 30%-35% efficient. Freewheeling is 100% efficient.

I am not following you in regards to freewheeling?

[voltage692]

Didn't the guy on Speedmakers say the brake regen was up to 70% efficient?

[dannyrrr]

This weekend I went down a 5000 ft mountain to sea level and i was at 7 bars and ended up charging all the way back to full...It was cool watching the mileage go back up, it actually said 50 miles (i knew that wouldn't happen as i was going to hit the freeway) but seeing it recharge was pretty neat.

[DonC]

I am not following you in regards to freewheeling?

Regen takes kinetic energy and turns it into chemical energy. Freewheeling doesn't involve conversion, so no losses. It just allows the potential energy to convert into kinetic energy to overcome losses.

[DonC]

Got a reference for that 30-35% estimate?

It's not an estimate but unfortunately the site won't let me post a link. It's the Mickey Bly interview with Greentech Today, November 23rd 2010. The regen discussion starts at 16:00.

[DonC]

I had a similar question for someone. How much of an incline would be required for the Volt to maintain to increase speed using just the "L" gear and no brake pedal? And also, how much energy would that give you per mile?

Only the vertical drop matters. The energy released in Wh would be given by mgh/3600. Just divide by 1000 to get kWh.