What a Joke!

[cfg83]

Hello -

Here I am defending GM again, go figure. I don't think of the Volt as a pure electric. It is a hybrid with a flexible drivetrain model. If the batteries get better, the all electric range goes up. If clean diesels make a splash in the US, it could have really great MPG. Notice this :

... General Motors has unveiled the Chevrolet Volt concept, the company's first plug-in hybrid vehicle, at the 2007 North American International Auto Show in Detroit ...

This is the "plug-in Prius" engineering model that the Prius "Electro-gearheads" have already proven can net 100 MPG.

However, from what I have read, Toyota will beat them to it and make a plug-in Prius before the Volt sees the lightbulbs of American car showrooms.

It definitely ain't the next EV1.

CarloSW2

[JanGeo]

I think the point is that it IS an all electric vehicle with an on board generator and NOT a series or parallel hybrid. Thus it is flexible in that any power source could provide the long range electric energy. Imagine an option of purchasing it without the ice.

[omgwtfbyobbq]

Your the owner's choice of battery capacity/ICE size? How could would doubling the EV range, and quartering the generator output for the same price be?

[JanGeo]

Well it would mean half the constant speed of 70mph if 1/4 the power ICE after 2 x 80 miles if traveling at 70mph since the 70mph speed was at 50% ice run time. If you were traveling at a lower speed then you could travel even further before you would have to slow down.

[omgwtfbyobbq]

It may be easier. Just allow the genset to rev higher and make more power, even if BSFC drops. I mean, I'd rather have a genset tuned for minimal BSFC at 55-60mph, the ability to make enough power to go 70-80mph, and more batteries, compared to something masquerading as a "performance" automobile.

[JanGeo]

You may not have that option - usually you ARE running at Peak Power if you are using a 1/4 HP rated generator - then again how often do you travel that far without slowing down. You can't have it both ways! Pushing the generator harder shortens its life, puts more demand on the fuel usage and creates more heat. That is the point of having one big enough to do the job - don't start falling into the American Car rut Need more power to Move more iron to burn more gas vicious circle.

On the other hand in the Winter time running an ICE to create some heat would be a good idea. My xB, now that it is that much more efficient, barely keeps me warm and if I crank up the heater fan the engine temp drops even while driving.

[The Toecutter]

Cars usually need about 1KWH per 5 miles so a 20KWH battery pack would be needed to go 40 miles. I just noticed that there is almost no travel room for the tires into the fenders and if the front wheels are turned . . . even less. 2777 Lithium cells weighting 444 lbs would be about a 20kwh battery pack and cost about $7000 with current pricing.

At 1 kWh every 5 miles, that would be an 8 kWh pack for 40 miles range, not a 20 kWh one. A 20 kWh pack would send it 100 miles at .2 kWh/mile. This 8 kWh pack would weigh ~180 lbs.

[omgwtfbyobbq]

Originally Posted by JanGeo

You may not have that option - usually you ARE running at Peak Power if you are using a 1/4 HP rated generator - then again how often do you travel that far without slowing down. You can't have it both ways!

I can if I'm not going to cruise down the freeway at 70mph. I don't mind putting around at 55mph, so if I can save money on the genset and add more batteries, while having the same or better efficiency at 55mph, even if I don't get the same efficiency at 70mph because the smaller genset needs to spin at 3,000+rpm, I wouldn't mind. I'd have farther all electric range, and a bigger battery buffer for the need to climb hills/accelerate quickly, and get the same or better mileage at the speeds I normally travel.

[JanGeo]

Originally Posted by The Toecutter

At 1 kWh every 5 miles, that would be an 8 kWh pack for 40 miles range, not a 20 kWh one. A 20 kWh pack would send it 100 miles at .2 kWh/mile. This 8 kWh pack would weigh ~180 lbs.

RIGHT - back to school for me - but factor in some DOD so they last more than 300 cycles and enough cells to output the peak watts.

I keep thinking about EEStor and their 15kwh cap pack and how that would take me 450-500 miles on my scooter with the same weight that I have now with the lead batteries . . .

[The Toecutter]

Current 18650 size Li Ions just aren't suitable for PHEVs. Even if you get 2,000 cycles out at 50% DoD for a pack that goes 40 miles at that percentage discharge, that's only 80,000 miles like. For 40 miles range at 50% discharge, now there's the 16 kWh pack, at $700/kWh, that's $11,200. For only 80,000 miles life, that's a huge operating cost.

Altairnanobatteries could really change this dramatically.

However, for a pure BEV with 250 miles range, a 500 cycle to 100% DoD, 50 kWh Li Ion pack is much more viable. Worst case scenario is 125,000 miles pack life, but in theory, assuming 2,000 cycles at 50% discharge, that's 250,000 miles pack life(not factoring in shelf life). Most people don;t drive 125 miles a day, so it would last a bit longer(in theory, but shelf life isn't factored).



In automotive volume, Li Ion would be $250/kWh, which would make both concepts cost effective. However, the pure BEV would be much more viable to consumers due to its pack life. You don't want to be replacing a pack during the vehicle's lifetime unless it is at most a few thousand dollars.

GM is pursuing one of the worst routes for a vehicle with this PHEV. If it wants to do a PHEV, it should be using Ovonic NiMH, which has much longer cycle life at deep discharge than 18650 size Li Ion. For 18650 size Li Ion, a pure EV is a much better fit, and is viable.

Or better yet, use Altairnano batteries if the technology really meets the hype.