[Deanwvu]

Sorry guys,

I know this info is in the forum somewhere already. I read it and forgot it.

It's going to be a 16kwh battery right? How much will be usable again? Somewhere around 50% or 60%? And that portion will get us 40 miles on all electric.


Again, I apologize, I just want to get this info staight so I can calculate my cost per mile when I am all electric in the Volt.

Thanks!

 

[Joshua Bretz]

It's going to be a 16kwh battery right? How much will be usable again? Somewhere around 50% or 60%? And that portion will get us 40 miles on all electric.

I think you got it right. About 8kW per charge, but I think that 40 miles is the end of life range, so probably about 50 miles when the battery is new.

But you know, this range is going to vary dramatically with driving conditions.

 

[JoeReal]

I think it would be nice if EPA should start publishing standards (with various driving profiles) for Electric Cars, and require sticker information such as:
miles per kWH in pure electric mode
mpg while on ICE (maybe better term needed).

That way we can compare various EV's or vehicles that can run in pure electric mode. This would be truly helpful as majority of us would most likely use the first few miles using electricity from recharging overnight, and would like to know if it meets most of our daily commuting needs.

 

[Jason M. Hendler]

Tesla Motors gets 225 miles from their 56 kWh pack for 4.02 miles per kWh.

 

[JoeReal]

Thanks Jason!

Aptera gets 12.5 miles per kWH in pure electric mode.

 

[Jason M. Hendler]

Thanks Jason!

Aptera gets 12.5 miles per kWH in pure electric mode.

Yes, Aptera is going for maximum efficiency - their drag coefficient is 0.14.

 

[Javan]

Yes, Aptera is going for maximum efficiency - their drag coefficient is 0.14.

I believe the Aptera drag coefficient is an even more remarkable 0.11! (Wikipedia) Of course it looks like that most efficient of swimmers (a dolphin), or flyers (a hummingbird), but I like the design. Lowering that coefficient is an amazing challenge to car designers I think. All the best, Jim

 

[Koz]

Lowering the drag is easy if you don't care about the practical applications and performance/safety of the vehicle. Trying to make a 4-5 seater that can carry more than a fanny pack that also has a coefficient below .25 is the challenge, especially when widths and lengths are constrained.

 

[Tom]

It is not a constant - it varies with conditions

I think it would be nice if EPA should start publishing standards (with various driving profiles) for Electric Cars, and require sticker information such as:
miles per kWH in pure electric mode
mpg while on ICE (maybe better term needed).

That way we can compare various EV's or vehicles that can run in pure electric mode. This would be truly helpful as majority of us would most likely use the first few miles using electricity from recharging overnight, and would like to know if it meets most of our daily commuting needs.

The attached plot shows how battery drain, and its effects on AER, varies with driving conditions for the EPA's City Driving Profile. The AER varies with profiles (aggressive driving, temperature, wind, etc.). Refer to post http://www.gm-volt.com/forum/newthread.php?do=postthread&f=3 for an explanation of details for the below plot.

 

[JoeReal]

Another thought would be to rate the ICE in combo with its generator:

how many kWH per gallon.

then if we know how many miles per kWH, we can get a really good idea about overall efficiency depending upon how we use the car.

 

[Joshua Bretz]

Another thought would be to rate the ICE in combo with its generator:

how many kWH per gallon.

then if we know how many miles per kWH, we can get a really good idea about overall efficiency depending upon how we use the car.

I think this is brilliant. If this were incorporated into marketing materials, it would really help people start thinking purely in terms of kW*hrs. That is, the point of the Volt is to shift attention from the gas station to the grid.

 

[Koz]

With EREV's it will be more complicated and there's is no way around it unless you want the ratings to be even less meaningful than they are now. In my estimation there will need to be:
KWh available
miles/KWh EV only city
miles/KWh EV only hwy
miles/gallon Extended mode city
mile/gallon Extended mode hwy

 

[JoeReal]

Since the vehicle is 100% run by electric, you just needed two things:
kWH/mile of the vehicle and
kWH/gallon of the range extender, ICE or fuel cell electric generator.

Then the kWH/mile can of course be subdivided into various driving profile categories such as City Driving, Freeway Driving, Mixed and other profile

BUT the performance of the specific range extender ICE or fuel cell electric generator remain constant regardless of driving profile (excepting perhaps various weather conditions), so its kWH/gallon fuel is very important to know. And you can easily translate the overall performance to mpg.

 

[JoeReal]

Another important thing that must be known is the useful kWH capacity of the battery pack. This is to determine the range between charges should anyone go pure electric mode.

the common denominator of all of these is the kWH unit of expression.

 

[KariK]

I think you got it right. About 8kW per charge, but I think that 40 miles is the end of life range, so probably about 50 miles when the battery is new.

Has GM confirmed that? Because it means even more than 5 miles/kWh! The other possibility that comes to mind is that the Volt gets 40 miles with a 50% cycle (30% to 80%) in the beginning and as the batteries deteriorate, the Volt just uses a bigger percentage! So at the end of ten years the battery can only store 13 kWh and the SOC goes from 25% to 85% (3 kWh to 11 kWh).