General Motors Exec: Less Than 2 Problems Per Million Chevy Volt Cells Produced

OCT 27 2015 BY ERIC LOVEDAY 86

First Gen Chevy Volt Battery Pack

First Gen Chevy Volt Battery Pack

During the recent 2016 Chevrolet Volt ride and drive event in California, Larry Nitz, General Motors’ vice president of electrification, commented on the durability of the battery cells in the original first-generation Chevy Volt.

According to Nitz, the cells have been nearly flawless.  Nitz confirmed what we already know from real-world experiences, there’s virtually no loss of range on Volts, even high-mileage ones.

But it’s this comment from Nitz that really caught our attention:

“We’ve seen what I would call pharmaceutical levels of quality in cell production. Of the more than 20 million cells that have been produced for the first generation Chevy Volt, we’ve seen less than 2 problems per million cells produced.”

So, assuming ~20 million cells produced, there’s been only ~40 problematic cells.  That’s extraordinary!

Validation Testing Of Volt Battery Cells Happens In Warren, MI

Validation Testing Of Volt Battery Cells Happens In Warren, MI

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86 Comments on "General Motors Exec: Less Than 2 Problems Per Million Chevy Volt Cells Produced"

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The Volt cells and pack seem to have been over engineered in a very good way. There are cars that have 200k+ miles and no range degradation. Perhaps it will be more of a calendar life issue, but even there, it has been 5 years now and the packs seem to be as good as new.
These packs may end up lasting (staying above 75% of original AER) for 10-15 years.
Ok, probably 8-12 but that is still pretty good. If replacement batteries really are going to cost less than $3000, that is a heck of a bargain. I can envision 15-20 year old Volts all over the place in 2030.

I think you’re right Ziv. The design of the Volt allows it to function well inside the high and low capacity of the battery has both extended the life of the battery and removed the chemistry degradation from sight of the normal driver. The other reason why I agree with your 10-15 year assessment is that range is not depleted over the life of the Volt. Yes, you may end up getting less AER, but that does not limit range which will keep a lot of old battery packs running in a Volt. Same phenomena has already happened with the hybrid Prius. Many drivers keep going on their battery if the health of the battery is deemed good even if the MPG has suffered. My daughter drove a Prius with 180K miles on the original battery before she ultimately upgraded to a Volt.

I got 1 million volts cells but a defect ain’t one.

+1

I have to disagree with this statement (in fact, I’d call it misleading):

“there’s virtually no loss of range on Volts, even high-mileage ones.”

The Volt has reserved battery capacity, so unless these cells are made out of kittens and rainbows, there will be a loss, it’s the nature of the beast.

It just isn’t as obvious to the typical driver.

Would love to see actual stats tho.

There was a lot of speculation that the Volt would open the charge window as the pack aged but I can’t recall ever reading a first person confirmation.

Replying to myself: I should add that the evidence certainly points to it. I would think calendar aging should be obvious by now, even given the life of temperate luxury the Volt’s battery enjoys.

maybe they got VW to write the software?

While it is true that ALL batteries – even the legendary Volt’s battery – degrade over time, the statement that you quote specifically talks about vehicle range and NOT battery capacity. Whatever the cause – be it opening the charge window, little to no battery degradation, or “kittens and rainbows” – the fact is that Volts have virtually no loss of electric driving range.

That’s like putting a 3000 mAHr battery in an iPhone and labeling it with 2000 mAHr and keeping the SoC in the Goldie locks range. After 3 years it’s “look the iPhone has 7 hours of use just like new”. Yet after 3 years and however many charge cycles, that 3000 mAhr is now a 2200 mAhr.
Except that the end user doesn’t know as we’ve told them it’s a 2000 mAHr battery.

It shows the conservative nature of the engineers at GM. They chose to pay for more unused capacity by keeping that charge windows smaller. This is not entirely a bad thing, particularly as the cost of batteries decreases.

And what’s not clear is whether or not they’ve really had to open up the capacity. Calendar-based degradation is drastically reduced by avoiding the fully charged and fully discharged extremes as they’ve done in the Volt.

Time spent at those extremes is where most of the time-based aging/wearing down of a battery comes from.

..and to expand, the selection of a maximal 65% DOD, or depth of discharge, has always been considered a conservative choice next to later PHEVs. Did we ever discover the ~10kwh discharge window begins and ends? Could it be 80% full and 15% from the original 16kwh?

I wish Apple did that with the iPhone. Over the life of the iPhone, I can easily plan my usage and charging based on a constant X-hours-of-use battery life. Apple could allow the user to tap into the reserve in case of urgent-need/emergency only after the user clicks on a disclaimer stating that using the reserve decreases battery life.

Is there an app that would limit charging to 80% of capacity if I should desire to do that daily with my iPhone of Android phone?

I’ve been limiting my iPhone’s charge to 80% for years. It’s quite simple, really; just unplug it. It charges at about 1% per minute, so I just plug it in in the morning for X minutes to replenish from (80-X)% before I leave for work. Very minimal effort, but is has a noticeable pay off. My wife’s iPhone showed signs of an aging battery after a couple of months. Mine is well over a year with no noticeable loss.

I do that with just about all my rechargable battery devices and most of them are lithium ion based which has shown a good result.

I’ve done that with my iPhone 6, I’ve only had it about a year so I don’t know how it’s benefitting the battery yet. I’m planning on keeping the phone for a long time so I hope this will help keep the battery healthy.

Not very convenient to have to monitor a phone battery charge. For $10 I replaced my battery in my old Samsung Note 2 and kept on going strong, even though I didn’t have a problem. I can charge it while I sleep with no concern.
Now a $3000 replacement for a Volt is a different story, they have to narrow the charge window so we can drive them to infinity. Actually not a great repeat sales plan, but we will take it.

Brian said:

“While it is true that ALL batteries – even the legendary Volt’s battery – degrade over time, the statement that you quote specifically talks about vehicle range and NOT battery capacity… the fact is that Volts have virtually no loss of electric driving range.”

Thank you.

It is not at all “misleading” to note that GM has engineered the Volt so well that, in most cases, there is no loss of EV range even with loss of battery capacity over time.

In fact, it is grossly unfair to GM to characterize this as “misleading”. GM deserves much praise for its superior engineering — in fact, I’d go so far as to say the astonishingly good engineering — of its first PHEV.

It would be wonderful if other PEV manufacturers also engineered their cars with a reserve in the battery pack, so that owners didn’t have to worry about loss of range as the years pass. Far from “misleading”, this should become the industry standard!

Nobody has been able to prove that GM opens up the window over time. It is only a suspicion by owners or many Volt critics without any understanding of how battery and its charging works. There are currently no “precise” way to accurately measure the capacity loss “without” fully charge and discharge the battery. You can only estimate based on some pre-determined charging curves but that is highly inaccurate. For BEVs, the algorithms are more accurate due to the fact they allow the battery to be fully charged or very close to the max so the amount of capacity can be measured. But for Volt battery that will NEVER gets fully charged, it is impossible for engineers to “accurately” measure the amount of capacity lost. The only possible way that engineers can do is to estimate it based on age and cycles combined with cell voltage during charge for a given amount of energy charged. That is only an estimate at best based on the cell characteristic. The problem with this approach is that if the cells degrade faster, then you don’t open enough windows so people will see the degradation. If the cells degrade slower, then you will actually… Read more »
ModernMarvelFan said: “There are currently no ‘precise’ way to accurately measure the capacity loss ‘without’ fully charge and discharge the battery.” At best this is an overstatement, since no plug-in EV maker designs their PEV to fully charge or fully discharge the battery. All production PEVs are designed to reserve some capacity on top and bottom, to prevent premature aging. So, ModernMarvelFan, whether or not it possible to measure the SoC (State of Charge) “precisely” or not, is rather irrelevant in practice. In practice, every production EV is able to sense its current SoC accurately enough to determine: 1. When the pack is fully charged (or more precisely, as close to fully charged as it’s engineered to be, which may be as low as 90%) 2. When a pack is so depleted that the car displays a “low charge” warning to the driver, and goes into “turtle” mode 3. When a pack reaches the full limit of discharge which it’s engineered to accept, and shuts the car down to prevent permanent damage to the battery pack Furthermore, some EVs clearly are able to discern intermediate levels of charge. For example, the Tesla Superchargers reduce the current fed into a battery… Read more »
PuPu wrote: “At best this is an overstatement, since no plug-in EV maker designs their PEV to fully charge or fully discharge the battery. All production PEVs are designed to reserve some capacity on top and bottom, to prevent premature aging.” But there is a huge difference between charging up to 95-98% than what Volt effectively does up to 75%. The difference in accuracy at those point is signficantly. Also, the curves near the top around 95% is very flat, so a little variance in voltage won’t result in much difference in actual capacity rating where at lower capacity point, the variance is much larger. That is why the I stated that unless Volt allows a “full charge”, you can’t measure it accurately. “So, ModernMarvelFan, whether or not it possible to measure the SoC (State of Charge) “precisely” or not, is rather irrelevant in practice. In practice, every production EV is able to sense its current SoC accurately enough to determine:” Why do I need to repeat myself over and over again on this point that every other EV allows full charge of their battery (as I have explained above to near full voltage mark) where Volt doesn’t, NOT even… Read more »
ModernMarvelFan said: “Why do I need to repeat myself over and over again on this point that every other EV allows full charge of their battery (as I have explained above to near full voltage mark) where Volt doesn’t, NOT even close.” Moving the goal posts? The assertion you have made several times, and this isn’t the first time I’ve taken issue with it, isn’t about whether or not EV makers allow their cars to be charged to “near full voltage”. Your incorrect assertion was that unless the pack is fully charged, it is impossible to determine SoC. Furthermore, you also incorrectly state that it’s impossible for any EV’s power electronics to determine the loss of capacity due to aging. And now that I think about it, I shouldn’t have cited 90% as the lowest maximum charge typically allowed. Both the Leaf and the Model S, in former years, had a standard 80% charge setting. Again, this would be impossible if what you said was true, because this is nowhere near full charge, so it would be impossible to determine that level of charge. You say the Volt is engineered to allow a maximum 75%? Perhaps so, but so far… Read more »
Pu Pu wrote: “Again, this would be impossible if what you said was true, because this is nowhere near full charge, so it would be impossible to determine that level of charge.” Now, let us look at all the stuff you wrote and you still havn’t provide any information on how the engineers can measure it precisely. At the end, you just proved my original assertaion is absolutely correct that NONE OF THE EV MAKER can measure the capacity loss precisely as I have repeatly asserted. Now, the goal post has been moved by you since you claim that “it is close enough” which is NOT what a precision measurement is. Now let us look at the real world data. Why do you hear about Tesla and Nissan make suggestion to owners to allow the car to discharge fully and then slowly charge back to 100% to get a better reading of the range and capacity? (That has been confirmed by many articles posted by various owners) That is clearly the evidence that they don’t measure the capacity accurate. Instead, by discharging it nearly empty and slowly charging it back to “100%”, the onboard charger and recalibrate itself to better… Read more »
BTW, if you or anyone here would care to explain to me how it is done in a detailed electrical engineering point of view, I am all ears. Just saying that “other BEV makers do it so Volt must do it” doesn’t work in logic here as I have explained. Now, let us at it this way if you actually understand electrical engineering. Max Volt cell voltage is about 4.15V. Obvisouly, nobody is even going to get close. Typically the cell is charged up to 3.7V for use. Tell me that how do I measure the amount of capacity lost beyond 3.7V if I never charge beyond that? Near the 3.7V mark, the battery charger is in a constant voltage mode with current decreasing at the voltage gets larger. The charger would have to stop at a pre-determined cell voltage by either measuring the cell voltage or left the charger at 3.7V and allow the current to be zero and then shuts it off. How does SW knows the behavior of the cell pasat 3.7V without getting there? Answer, by predicated model to track the cell vs current charging characteristic based on the model for the cell. There will always… Read more »
ModernMarvelFan said: “Max Volt cell voltage is about 4.15V. Obvisouly, nobody is even going to get close. Typically the cell is charged up to 3.7V for use. Tell me that how do I measure the amount of capacity lost beyond 3.7V if I never charge beyond that?” Obviously somebody has to take some cells and test them to destruction, and yes that will include charging to 100% and discharging them until they’re exhausted, and doing this repeatedly to find the effect of aging. The data is recorded and charts are made. But this is done by the battery manufacturer, who hopefully will make that available to his customers. Those customers who are designing commercially produced EVs will do their own battery testing in their own labs, so the auto maker’s engineers will certainly have plenty of data for comparison. It’s easy to determine current SoC when the batteries are new, simply by accurately measuring voltage. You claimed voltage is “very flat”, but there is sufficient variance that if you can measure the voltage precisely, you can determine SoC. Figuring capacity loss due to aging requires access to more data, but again this data is going to be available to anyone… Read more »

“in practice this won’t be 100% accurate; it will be an estimation. This can be seen by the fact that EV owners say that if you fully charge an EV’s battery pack, the car’s own estimate of range on a full charge may change slightly, as the car’s software recalibrates the pack’s capacity.”

That is my point all along. I have wrote repeatly that there is NO way that they can measure the capacity accurately and ONLY by using a prediction model which will not reflect each and every cell as they do vary. By charging it back fully, you can recalibrate the cells so the error gets smaller. But Volt never gets full so the margin of error is far greater.

I guess if you agree with me, then why are we going back and forth on this topic?

PM-PU, please stop acting like a drivers information center. This discussion was going so well. Then your attitude got out and turned this very educational topic into a turd toss. Stop doing this! You, and a couple of others, have spoiled so many of my visits to inside ev’s that I can only stand this site once a week at best, instead of looking forward to it every day.
PLEASE act like a mature adult when you people are here in a public. Thank you.

“Nobody has been able to prove that GM opens up the window over time. It is only a suspicion by owners or many Volt critics without any understanding of how battery and its charging works.”

Actually it was GM engineering that stated they had algorithms that did this, very early on when the Volt first started production.

Do you have any reference links to show that? I have never seen it. But if GM does, then it will be very interesting how they actually do that.

As I said, the only accurate way of doing so is by using “predicated” model based on cell voltage curves vs. capacity, but that is highly unreliable due to the number of cells used in a large pack.

I have been playing with rechargable battery for decades and I haven’t heard any precise ways of doing that at all beside predication model. That works decently for small number of cells in a shorter period of time, but for a large cell packs, it is not accurate.

At the end of the day, we know this for sure. GM engineer can open up buffers all they want. But at around 25% they run out of space to go. So, no Volt has lost 25% of the capacity so far and we know at least few LEAF that has lost more than 3 bars in the real world.

No, I don’t have a link. It was back in 2011 that I read that detail, in an interview on the GM-Volt.com site, IIRC.

I would think the Voltage windows can be opened based on measured energy discharge. They can measure energy taken out of the battery and use that to determine how to vary the voltage start and end points if they decide to slowly increase the buffer.

Edit: I found the link! Or at least a link. I am impressed at my memory, haha. Not sure where/who the info actually came from at GM though…

http://gm-volt.com/2010/10/26/chevrolet-volt-will-utilize-10-4-kwh-of-battery-to-achieve-ev-range/

“As the battery ages and energy storage capacity of the lithium-ion cells degrades, control units will widen the percent state of charge band to continue to deliver the range goal.”

You have a photogenic memory! 😀

Thanks for the links. I am curious on the 10.4kWh number since my Volt never say that since day 1, maybe I had a “bad battery” to start with.

Now, let us assume that is true and GM is doing it by using predication model similar to other EV makers. The following would be intersting point to analyze.

“battery will acutally be kept at a maximum 85% to 90% state of charge.

As the battery ages and energy storage capacity of the lithium-ion cells degrades, control units will widen the percent state of charge band to continue to deliver the range goal.”

So, once you open up the entire band reaching 85% to 90%, the owners will start to see capacity loss. So far, none of the real world owners have reporting such event. Isn’t that a good assumption that none of the Volt has lost more than 15% of the capacity yet? 2 bars on the Nissan LEAF is about 18-19% right?

ModernMarvelFan said:

“I have been playing with rechargable battery for decades and I haven’t heard any precise ways of doing that at all beside predication model. That works decently for small number of cells in a shorter period of time, but for a large cell packs, it is not accurate.”

This is one of the reasons that li-ion battery packs need a BMS (Battery Management System); to keep the cells balanced so they will all have the same voltage. Battery pack makers also carefully choose cells so their voltages exactly match. That’s why you can’t replace some of the cells in a pack with new cells.

But sure, if the pack gets out of balance, then it will become impossible to accurately determine SoC from the voltage.

“Battery pack makers also carefully choose cells so their voltages exactly match. That’s why you can’t replace some of the cells in a pack with new cells.”

Yes, I would agree that is the intent. But in reality, there is no way you can guarantee that every cell ages similarly. They don’t. They can be very close. BMS can measure the voltage and try to adjust but only to certain point. When they don’t behave similarly as predicated, the error will be even larger from the predication model which would result in even poor capacity estimate as you stated.

I have never read anything from GM stating it either. Do you have a reference?

Yes, link provided above.

Glad you found the link. PUPU and MMF have split that hair about as many times as you can.

Bill,

It still doesn’t show how GM does it. It is just a confirmation (assume the source is accurate) that GM does some kind of “capacity compensation”. But that still doesn’t show how they do it accurately. As I stated before, that is the ONLY way of doing it so far by using predication model and hope all your cells match them over time. But if the models are off, then the owners will likely see more range or less range depending on the direction of error.

My original statement was still correct. “Nobody knows how to make the capacity loss measurement accurately without fully charging and discharging them”. They all appear to use “predication model” which is ONLY an estimate. The closer you charge to 100%, the better you can recalibrate that model. Volt never gets close therefore, it doesn’t get the potential accuracy that others do.

My ROadster kept a running tab in the logs of the battery capacity. Was updated with every recharge.

Was there a bit of guesswork involved? Yes, but since the number was ‘revised’ at every charge, I had no problem believing it was a pretty good guess.

That I would believe.

As I said before, those BEVs would get a better recalibration each time as you may or may not reach “100% full charge”.

But in the Volt, you never reach the full mark so its predication would be potentially farther off.

Or GM got a real good manufacturing process control and somehow every cell are pretty much dead on with their models. Maybe that is the case with 2ppm failure rate. But I would hardly believe that is the case.

Either, as long as nobody notices any decrease in range, it would still mean that nobody has lost more than 15% of the range yet. That is an accomplishment by itself.

They talk about defect , not about degradation that is normal . Even then the degradation is still on the good side compare at some other.

Good news maybe now GM will begin production of more BEV models and not have constant recalls on their ICE vehicles.

When BEVs will be mainstream, car companies will try to be cheapter than everyone else as well. This again will go at the expense of quality.

Yes, there was just another one issued, actually a re-recall. A problem with a cracked seal which could leak oil onto the exhaust system and cause a fire. GM recommends not to park in a garage but outside. Something like 1300 hundred fires 250 of which were in vehicles that were already recalled and supposedly fixed.

For cars built pre-GM bankruptcy, pre 2004 models.

I read the same story as you do.

It is just a reflection of the poor quality or design of GM products that are pre-Volt era or pre-bankruptcy era.

The fact that you along with other haters who choose to bring it up on a Volt related topic clearly shows your motive and bias.

Yes, you are on the Volt hater list.

LG Chem is owning the battery industry right now.

I tip my hat to GM. Very good work General Motors.

The cells are made by LG Chem, so very good work, LG Chem!

GM’s engineers are the ones that chose to not fully charge or discharge their batteries, much more conservative than any other automaker.

So the original sentiment stands… Good work, GM.

Although I read your comment after other comments about battery pack life, so if you’re talking about cell defects, then absolutely yes, good work LG.

😉

Wonder had GM have chosen the LG Chen cells for the Spark EV from the beginning if we would have seen a lot more of it. Understandably GM wanted to hedge bets and sure enough one of the cell makers A123 went belly up.

Happens all the time …People in the background do all the work, while the People in the lime Light take all the credit….way to go GM!

A lot of you may want to learn what statical analysis is really about.

Of the statement produced,
– are all 20 million cells produced, used in the Volt? Or a certain %?
– What is virtual, i.e. what criteria are you defining virtual, for saying no loss?
– How do you define problem, i.e. that a problem is “a problem of certain type” or a problem is ANY problem?
– Do you start tracking problem only when it is placed and used in the Volt, or even during the manufacturing process?

These are just some of the real investigations on what really behind corporation speaks. I know – cause I used to do the same job 😉

Capacity loss is different from defect.

2ppm is impressive while electronic industry is running at 5ppm to 7ppm.

This is talking about defect.

I’m remember a graph GM unveiled around the time of the Gen 2 launch showing the battery degradation curves of the various Volt batteries. They showed the first batteries (2011-12), the second and third gen (2013-15), and then new battery. Anyone else remember this?

Anyways, I remember the chart showing that the battery for the first iteration would last 8-10 years, but the later iterations were better than that.

No surprise. GM had said that they battery was designed for the life of the car. And they had done extensive testing before releasing to the market. GM set the precedent with the 8year/100K mile battery warranty for the Volt, and others followed suit. Tesla did retroactively apply the warranty to older cars, which was mighty nice of them. Nissan reluctantly increased battery warranty for Leaf but with a boat load of pre-conditions (owners are required to sign a special warranty card for the battery). And older Leaf owners were left out. IN fact, many early Leaf vehicles in hot southern states had significant degradation of battery capacity

Best to fact check before rumbling out all the mumble jumbo you’ve written.

8 yr/100K warranty was standard – at least also for Nissan, since day 1.

What GM didn’t and still doesn’t have, that Nissan has, is what it’s called capacity warranty. It covers all the LEAFs, new and old, as long as it’s within the 5 years period. More importantly, only a small fraction of the early LEAF, which were mostly in the Arizona/New Mexico region had premature degradation, when compared to LEAFs of other regions, which Nissan actually either replaced or bought those LEAFs back.

P.S. The battery is actually from LG Chem, not GM.
P.P.S. No owners needed to sign any special warranty card for the capacity warranty to be effective, which, again, GM doesn’t have.

Nissan only offered the capacity warranty with specific numbers and timeframe after being sued in a class action lawsuit filed on behalf of Leaf owners that were experiencing significant degradation.

From the beginning, GM has offered a (better) battery capacity warranty: no more than 30% degradation during the 8 year/100k miles Voltec warranty. They didn’t need to be threatened by legal action to relent and offer a capacity warranty, like Nissan.

Odds are not a single Volt has had a battery replaced due to capacity loss yet.

*single Volt battery, that is

What you’re also missing is that Nissan allows for quite a lot of battery degradation before warranty coverage will kick in. It’s pretty common for a Leaf with only 30k miles (pretty much a new car by most standards) to have lost 10% of its range. That’s a very big deal when you’re cutting it so close with a 70-odd mile range to begin with. On the other hand, if you have a Volt, you will still have 100% of your range at 30,000 miles. The Volt was built to last as long (or longer) as any modern ICE car. The Leaf was effectively built as a lease-only car.

2012 leased Leaf with 34488 miles has lost 3 bars and has a range of 50 miles,a/c off, driving 5 miles below speed limit in central Florida.

bro1999 is right. You got it precisely backwards. Even now, Nissan’s 70% capacity warranty only extends to 5/50. VW (I recently leased an e-golf) gives 70% to 8/100 but they ladle on some extra cautions that may/may not be enforceable (don’t let it sit at high charge, don’t consecutively DC fast charge it, etc).

The BS Volt hater Londo Bell is back to spew BS again. “Best to fact check before rumbling out all the mumble jumbo you’ve written.” You should have done the same before you accuse of others. “8 yr/100K warranty was standard – at least also for Nissan, since day 1.” That is defect warranty and GM has 10year/150K miles warranty in California with AT-PZEV designation. “What GM didn’t and still doesn’t have, that Nissan has, is what it’s called capacity warranty. It covers all the LEAFs, new and old, as long as it’s within the 5 years period. ” Here is direct quote from GM warranty page: “Depending on use, the battery may degrade as little as 10 percent to as much as 30 percent of capacity over the warranty period. A dealer service technician will determine if the battery energy capacity (kWh storage) is within the proper limit, given the age and mileage of the vehicle” As much as 30%. If it is greater than 30%, GM will fix it. But since we haven’t notice any real world degradation in range, it hasn’t been a problem to call on unlike the LEAF capacity loss. Furthermore, Nissan didn’t offer any… Read more »

Bob Lutz always said the 2011 VOlt, since it had an 8 year, 100,000 mile warranty on the battery, had to effectively be a 10 year, 150,000 mile battery.

Besides LG’s excellent quality control (and apparently GM’s careful final assembly), it looks like the 2011 volt’s battery is indeed beefy enough to handle 150,000 miles.

For all my griping about the Volt, it’s been pretty bulletproof in the three years I’ve had it, and it’s built like a tank. It went toe to toe with a big Caddy and the mass kept the Caddy at bay. When my son starts to drive it’s definitely the car he’s getting.

Somebody needs to find a hack to open up the “usable” SOC.
🙂

Anonymous, you watched too much YouTube videos of people hacking into the BMW i3 Rex to make it functional. Hacking into the Chevy Volt would be a horrible idea. The designers of this vehicle did a great job. Leave well-enough alone!

Indeed.

GM, like Tesla, chose to design its battery pack to “baby” the cells, to ensure long life. Hacking the pack so you can use greater DoD would mean the pack would age faster… so you would lose capacity and range faster. Is that really what you want?

There’s also the matter of voiding the warranty, which that hack would certainly do.

I read some place, if you use the fast charge too often it can cause battery degradation. That’s probably why GM didn’t make the 2016 Chevy Volt quick charge capable.

The Chevy Spark EV has DC fast charging, and GM has stated that you can fast charge it as often as you like without degradation.

Also, tests have been run on the Leaf, with one car only being fast charged, and a second car only being charged with the on-board charger. They were both driven under the same conditions on a test track for 60,000 miles (IIRC) with no difference in capacity loss.

GSP

http://www.truedelta.com/Nissan-LEAF/reliability-968/vs-Volt-1048

I’m surprised the Volt numbers are as good as they are. I was expecting reliability worse than the Leaf.

As is it appears to be a wash on reliability.

Why would that be? Because its engines?

Keep in mind that engines on the Volt is rarely used so it will reduce wear and tear related problem signficantly. Even if Volt has 100K miles, using today’s Volt owner’s average, only 33K or so miles are gas miles. How often do you have poroblem with 33K miles engines these days?

Also, GM was really focused on “not to screw up” the Volt too much, especially with all the political spot light on it, so that helps a little bit as well.

Doug (dhanson865) said:

“I’m surprised the Volt numbers are as good as they are. I was expecting reliability worse than the Leaf.”

Good heavens, why expect that? GM designed their EV battery pack properly, with a liquid-based thermal management system to keep the battery from getting too hot or too cold. Contrariwise, Nissan took the cheap way out, making no effort at all to prevent the Leaf’s pack from getting — and more importantly staying — too hot or too cold.

It’s hardly surprising that the Leaf has had problems with premature aging of battery packs.

GM’s Voltec drivetrain has turned out to be everything I was hoping for.

And it keeps getting better every year.

Now I wonder what the performance benchmarks will be for the Gen3 version.

That is amazing QA. Well done LG Chem & GM.

My FORD Focus EV battery pack has also had ZERO degradation in over 3 HOT summers in the Phoenix AZ area. I only have 21K miles on it but the battery with liquid cooling and 90% max charge limit built in is great.

As a fellow Note deuce owner, I discovered accidentally a strangeness in that battery:

I too bought a replacement battery, but we have three of them and my daughter’s was Much worse than mine, so I took my ‘slow-first-charge’ new battery back out of mine for her to use, and I reverted to my 29-month old one. I then USB (i.e., SLOW) charged it back up and whatdya’ know? the battery life returned to the 12++hrs that I have enjoyed these many months.
(Still on that ‘dangerous’ 4.4.2 OS with few Google apps running, if anyone cares)

I hafta’ wonder if the ‘slow’ charge on the Volt has had a positive result for those batteries as well, does a high C rate degrade the batteries quicker? (studies, I mean) or has that been looked at. I’ll guess that the kneejerk reply would be the Tesla (Bjorn is 90% SC or thereabouts) but their battery is unique to them.. just wondering..

Phr3d asked:

“…does a high C rate degrade the batteries quicker?”

The short answer is “yes”. This is clearly shown in lab tests; consistently charging and/or discharging the batteries at a high rate causes them to age faster.

But the real question is this: Just how much effect does faster charging of the pack affect battery life? In general, EV makers say that an occasional fast charge won’t noticeably impact battery life. Some say that it’s only when you repeatedly charge/discharge the pack faster than normal, that premature aging happens.

Now, I’ve seen some claims from Model S owners who have used the Supercharger system heavily, and claim that they haven’t experienced premature aging. But one should be skeptical of the relevance of anecdotal evidence. And besides, the Volt isn’t the Model S. As they say: “Your mileage may vary”.

Plug in America’s survey of Leaf owners showed no difference in battery capacity loss based on frequency of DC fast charging.

Only hot temperatures and high mileage per year resulted in faster battery degradation.

GSP

Yeah, GM stated even before the 2011 came out that the battery could ‘take’ a 48 amp charge rate, but that it would be left to ‘aftermarket tuners’ to do that.

I guess no one found a business plan. If they did, Clipper Creek would sell alot more of their LCS-60’s.

I don’t think fast charging impact the battery life at all unless you are pushing beyond the acceptable range. Now what is clearly is the fact that heat is public enemy #1. Faster charging will generate far more heat (it varies on chemistry, some generates more heat than others). So, in many of the studies, it would be hard to seperate the two. On cars with better thermal controls, the faster charging don’t seem to be a factor as much. Even even the cooling design and cell design impact that slightly. For example, Volt uses plate to sandwidich the large format cells. It is more complex and more expensive, but it offers the best temperature gradient across the cell since there will be a full contact across and the large format cell are relatively thin. On the design that Tesla uses, the cells are mounted vertically with cooling tubes squeezing the cells on the outside for contacts. (at least from the pictures of the e-Rav4 packs designed by Tesla). Not all the surfaces of the cells are in contact with the cooling tube so there can be a slightly gradient between surfaces. In addition, even if the cells are in… Read more »
Glad to hear that they are reporting only 2 IPPM! That’s great news. Unfortunately, my Volt (MY2012) had nothing but problems. My Volt would not hold a charge. Forget about trying to drive 40 miles on a charge…I was happy when the car would have 5-10 miles on the battery after sitting plugged in all night or for 8 hours during the day while I was at work. I had over 36 open claims with GM & Chevrolet about my VOLT and countless times I took in into the dealership to be “fixed”. The response I always recieved was “no trouble found”. I sent supporting documentation (pictures, copies of electric bill, etc.) to the VOLT team as reference material showing that my VOLT would not charge. Even at work (at a designated VOLT charging station)…my Volt would NOT charge! Even with another Volt owners charging cord my Volt would NOT charge! For an electric vehicle…I put over 650 gallons of gasloine in my car which had about 24,000 when I turned the lease in 3 years later. For my experience, the VOLT did not live up to the hype and expectations. I’m disappointed and saddened that GM could not “fixed”… Read more »

I am sorry to hear that.

I have the exact opposite experience with the Volt which is also a 2012 model. The dealer wasn’t great by GM was very proactive contacting me if there was a problem. Luckily since my car has been away from the dealers, it has been working well.

I am curious about your charging problem which is actually new to hear. Was the car not charging or was it not holding the charge?

If the car is not charging, then the dash board light wouldn’t be green when you plug it in. Dealer should be able to find the problem. If the light is green and battery is not getting charged, then dealer should be able to find the problem as well with the onboard charger or battery system.