Cobos

I think this is actually a big point. People (people as in Joe public) probably wont see this themselves until they've had the car for a few years. But when you've got a range extender unless you drive exactly the same route every day for like 10 years you wouldn't notice as for every month after a certain period the RE starts up another 100 yards closer to your house... It's the same thing that happens to ICE cars now, they get crappier and crappier mileage as they age and as you put mileage on your oil change f. inst.

Cobos

vfx

What about the readout? There are many Prius drivers that slavenly look the numbers and adjust their driving for max mpg. The battery loss AND the ICE degradation will surely be noted.

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The world loves to be deceived.

Cobos

Readouts.... I remember the time when we had a odometer, a speedometer and a fuel gauge and we were happy. Oh wait...that is what my car got :) As I'm driving around in such an old car I tend to forget the newer cars has a lot better instrumentation than my old trusty one. I suppose that will show everyone what the status on the battery is...

Cobos

TEG

So, why does Fisker require you to start the ICE to get full power output from the eMotor?

Tesla is talking about Whitestar having even more eMotor power than the Roadster, yet they are talking about a REEV version with a much smaller (and less expensive) battery pack. I do think that battery power output capability could be an issue here.

Tesla is trying to use inexpensive commodity laptop cells (in large quantities). Sure you could get expensive cells with higher "power density", but they are trying to find solutions that use more "run of the mill" batteries.

I don't think my idea of running the ICE while the pack still has a lot of charge left is unfounded. I think we might see more applications designed to work that way. Letting the pack run to near empty before starting the ICE sounds good from a marketing standpoint, and works in an "ideal world" situation where people don't ever drive more than 40 miles between plugs, but I don't think that will work for everyone.

Does the mainstream want a "mock EV" that lugs around a big ICE generator for those days when you go over your BEV limit, or do they want a well engineered Hybrid that does use some gas, but with significant battery assist, and plug in capability they get effectively over 100 MPG?
I guess we will see which wins... The series PHEV Volt or the next gen PHEV Prius. If people only ever drive short distances, and always plug in long enough then the Volt may be the winner. If people do drive more than 40 miles frequently, or neglect to plug in sometimes then the Prius approach may end up with the higher effective MPG numbers.

AGR

A mid size family sedan with all the technolgy and safety features that customers expect with usually an aluminum ICE weighs over 3,000 lbs. with a carrying capacity of lets say 1,500 lbs for a GVM of 4,500 lbs.

This same mis size sedan fully electric would easely weigh an additional 1,000 lbs to accomodate the weight of a battery pack for a reasonable range for a GVW of 5,500 lbs which is getting into large sedan or pick up territory.

The Tesla Roadster starts out as a small very light ICE powered Elise, and turns into a very heavy Tesla Roadster(compared to the Elise). Putting an addtional 1,000 lbs (batteries) in a Camry would create several challenges.

The compromise is a battery pack and a small range extender.

TEG, has described a few scenarios of how it could work.

Also keeping in mind that most elctronics in modern cars have a genuine distaste for voltage fluctuations, they love to run on the alternator at 13.5 volts.

mt2

TEG, you make a very good point. Elsewhere, we discussed what happens to an engine and it's gas if you only run it once or twice a year.

I think my ideal situation would be an engine that produces only as much as or less than the power needed to sustain the vehicle at highway speeds. Suppose, for instance, that the genset kicks in when the battery is at 60% capacity. The battery would continue to drain if I was doing highway driving, but the range for the remaining 60% could be nearly indefinite depending on how I drive. Assuming I have to get off the highway once in a while to eat and use the restroom, regen would help extend the range further.

In that type of scenario, it would be possible to run the batteries to empty - especially as they age. But that would be really rare and a driver would have a lot more time to find a place to charge up. If I could get 400 to 500 miles before the batteries are drained, I could plan my road trips around that.

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Mark Tomlinson
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mt2

Oh, by the way, that would truly make the vehicle a Range Extended Electric Vehicle. I would expect a series hybrid to continue to run as long as there is gas in it. But a REEV doesn't get indefinite range; it just gets extended range.

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Mark Tomlinson
"I am not a trouble maker; I'm a catalyst for change."

Kardax

Everything Fisker says is subject to change. They don't even have a driveable prototype yet.

All of your statements about firing up the ICE before battery depletion assume a low-power battery (commodity laptop cells in particular). These cannot survive the heavy cycling of a PHEV usage profile. They can't be used in WhiteStar. Tesla must use a high-power, high-durability design like A123 or AltairNano (although it may not come from either of those companies).

Since Tesla must go with such a battery design, there is no need to run the ICE except when the battery is critically low.

It's going to come down to three factors: cost, range, and gasoline availability. The company that delivers the best balance of cost and range will be at an advantage. Any threat of a gasoline shortage will tip the balance in favor of range. A vehicle that has excellent performance (as WhiteStar is apparently pursuing) can justify a higher price, too.

-Ryan

stopcrazypp

For comparisons sake, in 100k miles (the proposed warranty on the battery) the Volt would fully charge 1750 times (since it lasts 40 miles until it reaches 30% charge). This would be true if the generator always went through the battery and you travelled the 40 miles in EV and the rest with the generator. This would also be true if you travelled exclusively on the battery regardless of the generator. So to allow the possibility of people who would travel exclusively on the battery, the battery will HAVE to last 1750 charges regardless if the generator bypassed the motor. So I guess you are right, Kardax, it doesn't really matter so much to the manufacturer whether the charge can go directly to the motor since the battery will need to last that long anyways.

However, if you were a person who travels more than 140 miles before you can charge, then the pack would only need to last 500 charges (typical commodity battery life) to last 100k miles, if the system can bypass the battery (an extension of this is that you can make an EV on commodity li-ion cells last 100k miles if the pack can travel 140 miles from full to completely drained). It is easy to see the implementation has a huge impact on battery life, but since the current cells supposedly last 7000 charges, it seems to make the argument moot.

I wonder what the advantages in performance each configuration will have. If the generator went directly to the motor with no battery assist, you would need a pretty strong generator to provide some decent performance, so I guess that would not be optimal. What I still don't know is if the performance will be better if the generator went exclusively through the battery (what you are proposing is the better solution) or if there was a mix (what TEG is proposing).

BTW the Volt was originally designed to fire the ICE up at 30% (don't know if they changed it though), so it's incorrect to say "there is no need to run the ICE except when the battery is critically low." I think if they want to keep decent performance and not just highway cruising, they will need to fire early and have a buffer regardless of how power dense the battery is (as you also can run into the problem of the charge depleting more quickly than you are charging the battery if there is no buffer). Though I'm not sure if the decision is based on preserving battery life (as it's bad to run li-ion fully down) or to preserve performance. I mean, since they have a generator on board anyway, it would be stupid to let the battery run down to critical levels and engage limp mode when you can fire it up early and prevent any negative effect on performance.

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TEG

Some of the talk about "charge to 80%" and "draw to 30%" could be based on the idea that battery life is substantially shortened if you try to push it to the limits. As Tesla mentioned, they plan to offer the option of a "less than totally full" recharge to help save the battery life. When Volt says they plan to fire the ICE at 30% they may mean that they have to do that to get expected battery lifespan. That lower 30% may be intended to never be used unless it was a dire emergency (such as you ran out of gasoline too).

Because of this there could be some "numbers games" played.
Someone could publish range numbers based on situations where you are "abusing" the batteries. In practice, most batteries don't like to be cycled between 0% and 100%. The Prius batteries are kept in a "happy range" to avoid early failure as well.

So, the firmware to control ICE behavior isn't just designed to maximize BEV only range, or improve performance, but it also needs to be designed to protect the batteries within some limits.

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The whole REEV thing brings up some debate... What qualifies to be called a REEV?

Is it just if the motive force is 100% electric motor? So what if you just take a Ford F150, and replace the transmission with a DC generator hooked directly to a DC motor. Then it is a 100% electric motor driven vehicle (although 100% powered by an ICE generator). I assume that this would not be called a REEV. But what if you put in a very small buffer battery that could give you 1 mile of electric motion with the ICE turned off. Would that be a REEV? I suppose so.

Customers are going to have to research their PHEVs to find what suits their driving habits.

Do you want a vehicle with a 10 mile battery pack, and large ICE?
How about a 40 mile battery pack and medium sized ICE?
How about an 120 mile battery pack with a very small ICE?