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What the Volt's gas engine can't do is completely recharge the battery pack to its full capacity. Rather, when load conditions are light the gas engine will send surplus electrons to the battery pack, which will also be receiving extra charge from regenerative braking, as well. That sounds about right to us, as we've always been told that constantly charging a battery to its maximum will shorten its life, as the optimum charge range is usually between 20 and 80 percent, not completely drained and not completely charged. GM is determining right now just how much it wants to let the gas engine charge the Volt's battery pack, but rest comfortably knowing that your future Volt won't be carrying around 400 lbs. of uselessness when the charge runs out.
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I think it will be wise to sit tight and see in November 2010 rather than being armchair critics or fanatics. Many things shall and will change be it good or bad between now and then.

At least it is good to know emotions (both positive and negative) are running high on this vehicle.

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  • 2 months later...
An extra helping of crow for GXT.

Really? Why? I'm not sure what I wrote that you are referring to. Are you blaming me for believing the now-incorrect GM PR? I think this just confirms what I've been saying, that GM is making up a lot of this stuff on the fly. Yes, crow for me.

I never understood what the fuss was about here. Why would you want the gas engine to recharge the batteries? It just means you are using gas to recharge the batteries instead of electricity through the plug. Doesn't that defeat the point of the Volt? Isn't the goal to have the engine run as little as possible? If this was so desirable why not get rid of the plug entirely?

But for some reason people are spazzing out because the Volt wasn't going to do something you didn't want it to do anyways. And now people are happy because it does something you wouldn't want it to do. And apparently I'm supposed to eat crow about something.

And yes, when the charge runs out the battery is still pretty very nearly 400lbs of uselessness (keep in mind that the usable capacity of the battery to begin with is only 50% so the battery is always at least 200lbs of uselessness). Because contrary to this article GM has confirmed that charging the batteries with the gas engine is undesirable.

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Because contrary to this article GM has confirmed that charging the batteries with the gas engine is undesirable.

Why is it undesirable if you can design the charging system to operate at a constant, optimal RPM for gas engine efficiency?

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Really? Why? I'm not sure what I wrote that you are referring to. Are you blaming me for believing the now-incorrect GM PR? I think this just confirms what I've been saying, that GM is making up a lot of this stuff on the fly. Yes, crow for me.

I never understood what the fuss was about here. Why would you want the gas engine to recharge the batteries? It just means you are using gas to recharge the batteries instead of electricity through the plug. Doesn't that defeat the point of the Volt? Isn't the goal to have the engine run as little as possible? If this was so desirable why not get rid of the plug entirely?

But for some reason people are spazzing out because the Volt wasn't going to do something you didn't want it to do anyways. And now people are happy because it does something you wouldn't want it to do. And apparently I'm supposed to eat crow about something.

And yes, when the charge runs out the battery is still pretty very nearly 400lbs of uselessness (keep in mind that the usable capacity of the battery to begin with is only 50% so the battery is always at least 200lbs of uselessness). Because contrary to this article GM has confirmed that charging the batteries with the gas engine is undesirable.

What part of "range extender" do you not understand?

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Why is it undesirable if you can design the charging system to operate at a constant, optimal RPM for gas engine efficiency?

Forget it, AAS: he totally misses the point. In his efforts to trash everything about the Volt (fear, perhaps?) he misses the point entirely. The 2-mode systems and the 'Synergy Drive' are overly complex. Why would you want 2 sets of drive systems? Why would you want a transmission (even a CVT) that continuously makes compromises between putting torque to the wheels and optimal fuel efficiency?

Perhaps the day will come when the Volt can run 300 miles on a single charge, but until that day arrives a small, efficient gas engine that operates only at one particular RPM as necessary is a beautiful compromise, to give those 30% of the driving public the ability to go beyond the 40 mile range that has been set as a target for the electric only mode.

Those with axes to grind are always shown naked in the face of facts.

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People were complaining about the styling, but this is not the car's worth.

It got plenty of attention at LAIAS, and I personally think it looks awesome, so I'm not worried. If the Prius sells on fuel economy alone, this machine should move units like the second coming.

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  • 5 weeks later...
Why is it undesirable if you can design the charging system to operate at a constant, optimal RPM for gas engine efficiency?

That assumes it could ever be as optimal as the plug. And if that is the case then why bother with the plug at all? Just use the engine all the time.

The goal is to use the gas engine to keep you driving until you get to the next plug, not to replace the plug.

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Do tell. What part of "range extender" involves chargine the batteries beyond what is needed to extend the range?

The system will keep the batteries somewhere between 20% and 80% charged. The NAV system is also suppose to be smart enough that it will know when you are headed home and only use the gas engine to charge the batteries enough to get you there.

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The system will keep the batteries somewhere between 20% and 80% charged. The NAV system is also suppose to be smart enough that it will know when you are headed home and only use the gas engine to charge the batteries enough to get you there.

Last told by GM it is actually 80 and 30. The ICE will attempt to maintain the minimum 30% state of charge for two reasons:

1) Deep discharges will shorten the life of the battery.

2) The ICE is unable to produce as much electricity as the electric drive will pull from the batteries. This could cause the car to go into a limp mode if there weren't sufficient reserves. Apparently it is still a possibility if you were going up a large hill, but it isn't overly likely to happen (e.g. 50% charge gets you ~32 miles on a flat highway with no AC. Going up a long incline at high speed with the heat on you could chew through that 30% reserve in perhaps 10 miles).

Last word from GM is that that Nav functionality will not happen. I believe the comment was something along the lines of, "Are you going to risk damaging your extremely expensive battery to save a couple dollars of gas?"

I just re-read my initial post. Perhaps replacing the "Why would you want the gas engine to recharge the batteries?" with the more explicit "Why would you want the gas engine to COMPLETELY recharge the batteries?" makes my meaning more clear.

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Forget it, AAS: he totally misses the point. In his efforts to trash everything about the Volt (fear, perhaps?) he misses the point entirely. The 2-mode systems and the 'Synergy Drive' are overly complex. Why would you want 2 sets of drive systems? Why would you want a transmission (even a CVT) that continuously makes compromises between putting torque to the wheels and optimal fuel efficiency?

I guess that is why the Volt will be so widely available, so inexpensive, so cost effective as compared to the Prius?

On the other hand, some argue that the Volt is an overly complex electric car in that it still needs the gas drivetrain, a plug, etc.

Perhaps the day will come when the Volt can run 300 miles on a single charge, but until that day arrives a small, efficient gas engine that operates only at one particular RPM as necessary is a beautiful compromise, to give those 30% of the driving public the ability to go beyond the 40 mile range that has been set as a target for the electric only mode.

There is no doubt that it is all about compromises and timing. As per the EV1, GM's timing still seems a bit off. The Prius and the Insight are the correct place to be right now. GM lost that battle and they are hoping to distract you with their fancy future-car instead.

Those with axes to grind are always shown naked in the face of facts.

I guess that would explain why you think the relatively available and inexpensive (and more importantly, infinitely more "existing") Prius is the complicated compromise and the Volt isn't.

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"Why would you want the gas engine to COMPLETELY recharge the batteries?" makes my meaning more clear.

I understood your meaning to be just that. The ICE won't completely recharge the batteries. It'll just get them to 80%. I'll concede that I was wrong about the 20% v 30% of the lower threshold, but my point stands.

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I guess that would explain why you think the relatively available and inexpensive (and more importantly, infinitely more "existing") Prius is the complicated compromise and the Volt isn't.

The Pruis is way overly complicated. Just because Toyota made it work doesn't mean it is the right way to go about doing it.

The Insight, and this is assuming the basic layout of the powertrain is the same as the current Civic hybrid, is actually the simplest design of all.

What is interesting about these two different hybrid models is that GM took some basic concepts from each one and assimilated them into their 2-mode hybrid design.

The Volt is still a completely new way of doing things and as such, it's untested. The most similar power train configuration out there would be Diesel-Electric locomotives, but the scale is so different as to not be relevant.

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IMHO that they have been playing with this kind of idea since the late 1930's with EMD makes a difference. It is a difference of scale, but perhaps some of the technology and ideas sury cary over, yes?

Chris

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The biggest difference between Electromotive and the Volt is the battery. In a locomotive the engines never shut off*

*GE has developed a hybrid locomotive and I'm not sure how that technology works yet.

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I understood your meaning to be just that. The ICE won't completely recharge the batteries. It'll just get them to 80%. I'll concede that I was wrong about the 20% v 30% of the lower threshold, but my point stands.

The ICE won't charge the battery to 80%. It will just try to maintain the minimum (30%).

The 80% state of charge is the maximum to which the PLUG will take the batteries.

The question still stands: Why do you want the ICE to charge your battery to 80%? That makes the plug useless.

It might also be worth mentioning that the ICE can only generate under half electricity that the the Volt can put to the ground. Therefore it isn't like the ICE is going to be generating a huge surplus of energy.

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The ICE won't charge the battery to 80%. It will just try to maintain the minimum (30%).

The 80% state of charge is the maximum to which the PLUG will take the batteries.

The question still stands: Why do you want the ICE to charge your battery to 80%? That makes the plug useless.

It might also be worth mentioning that the ICE can only generate under half electricity that the the Volt can put to the ground. Therefore it isn't like the ICE is going to be generating a huge surplus of energy.

If the ICE will only take the batteries to 80%.... and the plug will only take the batteries to 80%... doesn't that make 80% the new 100%?

To your last point, that only matters if you're at full throttle all the time.

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If the ICE will only take the batteries to 80%.... and the plug will only take the batteries to 80%... doesn't that make 80% the new 100%?

The ICE DOESN'T take the batteries to 80%.

I wrote: "The ICE won't charge the battery to 80%. It will just try to maintain the minimum (30%). "

Why are we having such problems communicating here?

The Plug tries to keep the battery 80% charged.

The ICE tries to keep the battery 30% charged.

In general, the Volt tries to keep the battery between 30% and 80% charged.

And the 80/100% distinction is important because, when combined with the 30% minimum, it means that the Volt really is really hauling around twice as much battery as it tries to use.

Edited by GXT
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That assumes it could ever be as optimal as the plug. And if that is the case then why bother with the plug at all? Just use the engine all the time.

The goal is to use the gas engine to keep you driving until you get to the next plug, not to replace the plug.

There doesn't need to be an assumption on the ICE being as optimal as the plug. Designing the ICE charging system to run at an optimal RPM is good/smart Engineering. The whole point of using the plug, besides it possibly being more efficient then the ICE, is that that electricity doesn't have to be produced using petroleum ('foreign oil') based energy sources.

...

And the 80/100% distinction is important because, when combined with the 30% minimum, it means that the Volt really is really hauling around twice as much battery as it tries to use.

It means that there is a FACTOR OF SAFETY! Once again, good Engineering will include a factor of safety (some level of over-Engineering, for the rare occasion that an application demands it).

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There doesn't need to be an assumption on the ICE being as optimal as the plug. Designing the ICE charging system to run at an optimal RPM is good/smart Engineering. The whole point of using the plug, besides it possibly being more efficient then the ICE, is that that electricity doesn't have to be produced using petroleum ('foreign oil') based energy sources.

It means that there is a FACTOR OF SAFETY! Once again, good Engineering will include a factor of safety (some level of over-Engineering, for the rare occasion that an application demands it).

Eh, it's done more because draining the battery below 30% or leaving it 100% charged on a regular basis dramatically shortens the effective life of the battery. It's one of the limitations of the type of battery GM chose to use for this project, but it's still the best compromise of size and power delivery that battery technology allows currently.

-RBB

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There doesn't need to be an assumption on the ICE being as optimal as the plug. Designing the ICE charging system to run at an optimal RPM is good/smart Engineering. The whole point of using the plug, besides it possibly being more efficient then the ICE, is that that electricity doesn't have to be produced using petroleum ('foreign oil') based energy sources.

If that is your goal, again, why would you want to charge the battery with the ICE?

The point of this thread has been questioning why someone was outraged about the ICE not charging the batteries and why anyone should be happy now that they hear it is possible,

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Eh, it's done more because draining the battery below 30% or leaving it 100% charged on a regular basis dramatically shortens the effective life of the battery. It's one of the limitations of the type of battery GM chose to use for this project, but it's still the best compromise of size and power delivery that battery technology allows currently.

-RBB

But then you have to question if the purpose of the battery for makes sense.

This is what was a bit maddening about all these claims that GM had done some sort of technological leap over Toyota. There are limitations and compromises to the Volt and the Prius. The reality is that the Volt needs an extra large battery to achieve some bone-head~80%-of-commuter's-range target and then needs to use a more expensive and less available li-ion batteries to make it possible and then needs to haul around way more of these expensive and in limited supply batteries yet to accommodate some of the limitations of the li-ion battery as well as your design.

That means expensive and low supply. But then they say it will be a relatively inexpensive mass-market Chevy. Is there any wonder I questioned the feasibility of this and how much GM had thought it through and/or was blowing PR smoke?

I guess when you can just sell cars at huge loses and your government pays for it you can do that kind of thing. But don't pretend that it is some sort of technological advantage that is holding everyone else back.

(On a related note, the E-FLEX Cadillac concept looks very nice and putting E-FLEX in a limited availability and high cost vehicle rings a lot more true to reality.)

Edited by GXT
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But then you have to question if the purpose of the battery for makes sense.

Of course it makes sense. Internal combustion engines are only about 20% efficient, yet you don't see anyone questioning its use. No it's not perfect, but it's better than what's available today.

This is what was a bit maddening about all these claims that GM had done some sort of technological leap over Toyota.

They have made a technological leap. The Volt is an electric vehicle that uses an ICE to extend the battery's range. The Prius is primarily motivated by the engine, and uses the electric motor for assistance in acceleration and for short-duration, low(ish) speed, low-stress cruising. The LiIon battery, imperfect though it is, has far greater capacity than the NiMH batteries in the current Prius.

There are limitations and compromises to the Volt and the Prius.

Agreed.

The reality is that the Volt needs an extra large battery to achieve some bone-head~80%-of-commuter's-range target and then needs to use a more expensive and less available li-ion batteries to make it possible and then needs to haul around way more of these expensive and in limited supply batteries yet to accommodate some of the limitations of the li-ion battery as well as your design.

Again, the battery is bigger (Prius Battery = 99 lbs, Volt Battery = 375 lbs) because it's expected to discharge more energy over a much longer period of time. A NiMH battery pack expected to power the same vehicle would be even heavier.

That means expensive and low supply. But then they say it will be a relatively inexpensive mass-market Chevy. Is there any wonder I questioned the feasibility of this and how much GM had thought it through and/or was blowing PR smoke?

They're expensive and in low supply because the demand was not there. Ramp up demand and you have impetus to create LiIon battery arrays in higher volumes. Higher volumes bring lower prices.

I guess when you can just sell cars at huge loses and your government pays for it you can do that kind of thing.

It's good thing Toyota's never gotten any help from the Japanese government, then.

But don't pretend that it is some sort of technological advantage that is holding everyone else back.

They drove the market for a plug-in hybrid with LiIon batteries when other manufacturers sait it wouldn't be feasible. That's not taking a technological advantage?

-RBB

Edited by RBB
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Of course it makes sense. Internal combustion engines are only about 20% efficient, yet you don't see anyone questioning its use. No it's not perfect, but it's better than what's available today.

GM does have everyone comparing something that they haven't delivered and won't deliver for a couple of years to what is available today. They also have everyone ignoring the limitations and the downsides of what they may deliver. These are all neat PR tricks more than technological marvel.

But when you actually consider REALITY and not just the positive, I'm not sure it actually IS better than what is available today.

Compare it to the Insight, for example. It will be on sale in just a couple of months. According to the European tests it will get ~10% better city fuel economy than the current Prius. It will sell for sub $20,000 and I assume Honda will still make a profit. They plan to sell 250,000 per year.

It won't be as flashy, but the amount of fuel saved by the Insight due to unit volume will dwarf that of the Volt. Honda plans to have sold 500,000 of them by the time GM has made 10,000 Volts at the end of 2010 (if they hit their own targets). By the end of 2015 GM plans to have sold 200,000 Volts. Honda plans to have sold 1,750,000 Insights.

Now consider:

If an average American drives 15,000 miles per year then a car that gets 25 MPG would use 600 gallons.

The Insight should get around 48 MPG. That is 312.5 gallons used and a savings of 287.5 gallons over the 25MPG car.

Let's assume a Volt drives about 12,000 of those miles gas-free. Let's even assume it gets 50 MPG when on gas. That is 60 gallons used and a savings of 540 gallons over the 25MPG car.

See the problem yet? The Volt saves less than twice as much fuel as the Insight but uses perhaps 10 - 12 times the battery capacity to do it.

By 2015 the Insight will have saved ~2,000,000,000 gallons of fuel as compared to the 25MPG vehicle. By that time the Volt will have saved ~325,000,000, or only 16% of what the Insight has saved. And I think I am presenting pretty much the best case situation for the Volt given that I don't think most owners will experience 50MPG or 12,0000 miles electric.

They have made a technological leap. The Volt is an electric vehicle that uses an ICE to extend the battery's range. The Prius is primarily motivated by the engine, and uses the electric motor for assistance in acceleration and for short-duration, low(ish) speed, low-stress cruising. The LiIon battery, imperfect though it is, has far greater capacity than the NiMH batteries in the current Prius.

That isn't a technological leap. If there is a technological leap (and it hasn't happened yet), it will be on the part of whoever makes the electric storage cost effect, compact, light, and quick to charge. It is all relatively trivial save the battery, and GM is just buying that from someone else. How hard it is to build a Volt? Just take the Prius, add a bigger electric engine, buy a bigger li-ion battery, and remove the gearing that allows the engine to turn the wheels. Of course you also have to cut production, double the price, and still sell at a loss.

Again, the battery is bigger (Prius Battery = 99 lbs, Volt Battery = 375 lbs) because it's expected to discharge more energy over a much longer period of time. A NiMH battery pack expected to power the same vehicle would be even heavier.

I'm not attempting to debate the ultimate merits of NiMH vs Li-Ion. What I am questioning is the timing and how it is being used.

They drove the market for a plug-in hybrid with LiIon batteries when other manufacturers sait it wouldn't be feasible. That's not taking a technological advantage?

First off, who said it "wouldn't be feasible"? If you said "not feasible now" I and Toyota would agree. So would GM... they don't use Li-ion in their current hybrids either. If you said "bad idea" I and Honda would also agree based on the reasoning above. The reality is that Toyota has a mass-market product they have to sell shortly and at a profit whereas GM isn't constrained by any of those items. It is all about timing. By the time the Volt comes out things may have changed.

As for driving the market, what they've actually done is cause chaos. Most everyone is tripping over themselves trying to follow GM right off the cliff. It is a brilliant tactic and we see it all the time when a company is not currently competitive. Distract when you can’t deliver.

Cost-effective mass-market hybrids are what the automakers should be putting their money into. By focusing on the Volt instead of their own inexpensive mass-market hybrid GM will have effectively cost 1,675,000,000 gallons of fuel from their own fleet 2015 (as per the numbers above). If you assume that they have distracted even 2 other automakers in the same way, that is over 5,000,000,000 gallons of US-security-depriving fuel that GM and the Volt will have consumed.

Edited by GXT
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Looks like things are even more in the Insight's favour now that some more stats have come out.

Although the predicted EPA rating is "only" 40/43, people seem to be getting 60 MPG fairly easily.

ABG: 63.4:

http://www.autoblog.com/2009/01/11/abg-fir...sight-63-4-mpg/

Jeff from VTEC.NET was at an event and managed in the low 70s and everyone else at the drive got in the 60’s.

http://www.vtec.net/forums/one-message?mes..._item_id=808664

C&D drove as tough as they could (which I imagine was still a fairly underwhelming event) and they still got low 40s.

Not only that, the battery pack is on 0.58KWh. No mention of weight/volume, but they did manage to put it between the wheels and get a 40/60 split seat.

So the average Insight will use 55% more fuel than the Volt (under pretty much best-case conditions for the Volt), but the Volt's battery requires ~2700% more capacity than the Insight's!

Edited by GXT
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