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Recently I lost some of my confidence in my Volt when it died on the side of the road. It turned out not to be the traction battery, thank goodness, and I'm back on the road with the Guessometer predicting 43 miles from the battery this warm June morning. But after this breakdown occurred I started reading more posts on this forum and I see that replacing the traction battery can be very, very expensive. My Volt is no longer under warranty due to its age (it's a 2013 put into service Jan. 31, 2014), although it only has 63,000 miles on it -- most of those miles on electric. So lately I've been wondering -- why do some Volt traction batteries seem (from accounts I read on this forum) to fail or die "early"? Were/are they defective, i.e., improperly constructed, or was it something in their treatment, something in the way they were driven, or were the conditions/temperatures somehow destructive? Do we have any actual figures as to the percentage of Volts that have suffered traction battery failure and how old or how many miles those batteries had on them when they failed? Are there any good statistics about this or is all the information anecdotal? And, is there some indicated point at which I should sell or trade in my Volt, while its battery is still (apparently) in good shape?
 

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This is getting to be a very common subject of discussion. Probably battery state of charge and temperature are important. My 2011 with 168,500 on the odometer is fine. It’s always plugged in, and lives in a temperature controlled garage no colder than 45 winter no warmer than 70 summer. However I’m sure there are many which are aging and fine stored outside and charged less frequently. Avoiding being parked in super hot has been discussed before. So don’t park in 90+ temps with zero charge and not plugged in.
 

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My used 2012 was a Southern car so I’m assuming it was used as a daily commuter and left outside work in a hot parking lot without a charge. The HV battery failed at around 76,000 miles. I have no idea how the previous owner drove it or stored it, but the “left outside with zero charge” is my best guess. Probably best to keep these things charged when storing the car if possible and avoid extreme temperatures.
 

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Why do some engines fail early and some don't? Or transmissions? It's often not knowable. And don't forget that software also plays a part in this... there was a recall to update software because it wasn't properly balancing cells. So many Volts spent years with possibly un-balanced cells, which to me is likely the greatest risk for pack failure out there (that we know about). And even if you updated your software, a lot damage could have already been done and it's just a matter of time (I could almost see a class-action due to this, though it would probably be hard to prove).

But the generic answer is: the worst things for packs are being at high states of charge and high temperatures. So if you lived in AZ and would park a near-fully charged Volt outside all the time, that would be bad (see all the Leafs with huge degradation in AZ). Though range loss isn't necessarily the same as pack failure. Batteries are complicated... we really need a service that can analyze a pack and just replace a handful of marginal cells... like a little pack overhaul, for a reasonable price.
 

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Some of the earlier gen 1's had faulty temp sensors, and since the sensor are embedded inside the battery, the whole section has to be replaced. When that happens you'll get the 'battery too cold, plug-in to warm' message, even if it's 80 degrees outside.

I'm assuming OP is talking about cell failures though. I have no idea why that happens, other than the things that have already been mentioned.
 

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... we really need a service that can analyze a pack and just replace a handful of marginal cells... like a little pack overhaul, for a reasonable price.
Exactly! The Volt pack was never intended to be serviced at the cell level. Knowledge gained from others on this forum and elsewhere indicates that if one cell in a pack drops out, the controller shuts the whole pack down, likely to prevent a runaway event leading to fire.
gm's new Ultium battery platform was engineered precisely to be easily serviced. A module or cell can be isolated electronically to allow the rest of the pack to remain in service. The only drawback would be a slight decrease in overall range. This service should be quick and inexpensive and likely proprietary.
something in the way they were driven
Very likely as a thing can only handle so much abuse. Imagine the strain on a cell with repeated excessive draws at low state of charge. This is why buying used is risky. Very difficult to determine pending failure with EV's. With ICE, you can use your senses to determine the health of an engine in minutes. Vibration, smoke, clacking etc...these conditions are just not present on electric drivetrains.
 

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gm's new Ultium battery platform was engineered precisely to be easily serviced. A module or cell can be isolated electronically to allow the rest of the pack to remain in service. The only drawback would be a slight decrease in overall range. This service should be quick and inexpensive and likely proprietary.
The potential is there. Ultrium modules seem to be 12.5kwh of pounch cells, and at least the modules are interchangable and usable in multiple configurations, and a typical skateboard can contain between four and eight modules. How this is LIKELY to work from a service standpoint is that when a cell fails, the module drops out of use (not the cell) even thought that could cut up to 1/4th the range, and the owner puts in for service. Service dept orders a refurbished module, drops the skateboard, swaps modules, and sends the one with the failed cell back for refurbishing, which replaces the bad cell and any others below a quality threshold for refurb modules, and puts it back in the pool. I'm guessing, but I'd expect this kind of service to be more along the lines of $1000 per module all in instead of $10,000, and take more like two hours of labor than two days.
 

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Thinking there will a whole new set of dashboard icons for us to enjoy. The "check engine" light seems so yesterday. How about a "check battery" or "service has been scheduled" message. Or series of dollar signs will work too, $=1000 $$=2000 $?!*&=you don't wanna know. Exciting tech though. To focus on the service end of things will keep gm's cars rolling along for years, and the service techs employed. These $10G Volt pack stories are scrarry.
 

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-- why do some Volt traction batteries seem (from accounts I read on this forum) to fail or die "early"? Were/are they defective, i.e., improperly constructed, or was it something in their treatment, something in the way they were driven, or were the conditions/temperatures somehow destructive?
Unless you live in the desert, I doubt there is anything an owner can do other than charge to full daily (including time to rebalance the cells), and leave it plugged in whenever possible. It's simply the state of battery technology and manufacturing. A microscopic defect in a cell, like a section of a hard drive, will grow over time.

Do we have any actual figures as to the percentage of Volts that have suffered traction battery failure and how old or how many miles those batteries had on them when they failed? Are there any good statistics about this or is all the information anecdotal?
Only GM knows, and they collect detailed information as it helps with their analysis. However they are not sharing.

And, is there some indicated point at which I should sell or trade in my Volt, while its battery is still (apparently) in good shape?
Once the value falls below the repair cost, just know the vehicle will be financially totaled (junkyard value). Although all cars are depreciating assets, once you reach this point it's unlikely putting in a another used battery will make sense in the long-term ownership scheme of things given the high cost. Either accept the risk, or sell at that point and put the money into the next vehicle.


Thinking there will a whole new set of dashboard icons for us to enjoy. The "check engine" light seems so yesterday. How about a "check battery" or "service has been scheduled" message. Or series of dollar signs will work too, $=1000 $$=2000 $?!*&=you don't wanna know. Exciting tech though. To focus on the service end of things will keep gm's cars rolling along for years, and the service techs employed. These $10G Volt pack stories are scrarry.
And the problem also is this cost isn't for new packs, they're used/refurbished. A new pack with a new 8 year/100,000 mile warranty would be different.
 
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The problem is those of us that bought a used vehicle without knowing how much abuse the pack has taken will have to either pony up for a battery or junk the vehicle. I bought mine for $10k, spent another $10k 6 months later when the battery failed, and now my CVT is getting repaired for another $2k. For those who took out loans on the vehicle and now have a $500 paperweight, that’s even more painful. I agree it’s not like an ICE car where you can tell if an engine or trans was abused, this thing drove until (1) the battery just flat went out and (2) the CVT wouldn’t move one day when I put it into “D”. And no, trading it in was not an option. Nobody would take it for even 1/10th of what I have in it.
 

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The problem is those of us that bought a used vehicle without knowing how much abuse the pack has taken will have to either pony up for a battery or junk the vehicle. I bought mine for $10k, spent another $10k 6 months later when the battery failed, and now my CVT is getting repaired for another $2k. For those who took out loans on the vehicle and now have a $500 paperweight, that’s even more painful. I agree it’s not like an ICE car where you can tell if an engine or trans was abused, this thing drove until (1) the battery just flat went out and (2) the CVT wouldn’t move one day when I put it into “D”. And no, trading it in was not an option. Nobody would take it for even 1/10th of what I have in it.
If I was in your shoes, I'd repair the Drive Unit also as long as the tech has a positive opinion on the outcome, which it sounds like he does. For all the money you have in it currently, you really need to get a few years use out of it. Where I would have diverged would have been the battery replacement.

As for mine, I'll be hitting 90k miles in the early Fall, and the warrantee will be going soon after that. I've settled on rolling the dice and holding on to mine for while, pending nothing substantial happens. I'd like not to have a car payment for a few years. Hopefully the battery chemistry in the Gen2's will be more reliable.
 

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100k miles on my 2011, it's still doing fine. Kept in the garage, plugged. As noted by flyingsherpa, heat not cold is going to prematurely age any battery, car or not. Plugged in, the Volt can cool it's battery.
 

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While there has been some increase in the chatter regarding battery failure, the number of replacements due to battery degradation still appears quite low. As of 2019, GM confirmed that "so far, these cases account for less than .01% of plug-ins sold by the automaker."

 

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While there has been some increase in the chatter regarding battery failure, the number of replacements due to battery degradation still appears quite low. As of 2019, GM confirmed that "so far, these cases account for less than .01% of plug-ins sold by the automaker."

That would be correct, IMO, if you are playing a game of semantics. There has to be other Volts out there where the pack just flat out failed, one day, due to issues “other than battery degradation.” Most 3rd party warranty companies call this failure “excessive wear and tear” but don’t cover it. And of course, they deny the warranty even though we know it’s basically the same thing.
 

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I believe that an owner of a Volt can view the health of his battery by using an OBDII scanner and the MyGreenVolt app with the 99 cent add-on. The voltage of each individual cell is shown. If one (or more cells) is weak, the inability to hold a charge is graphically shown and enumerated.

OBDIIs can be inexpensive. This one works for me with the MyGreenVolt app:
https://www.amazon.com/Vgate-Elm327...MVI8/ref=dp_prsubs_1?pd_rd_i=B01FU5MVI8&psc=1
 
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Discussion Starter · #16 ·
I believe that an owner of a Volt can view the health of his battery by using an OBDII scanner and the MyGreenVolt app with the 99 cent add-on. The voltage of each individual cell is shown. If one (or more cells) is weak, the inability to hold a charge is graphically shown and enumerated.

OBDIIs can be inexpensive. This one works for me with the MyGreenVolt app:
https://www.amazon.com/Vgate-Elm327...MVI8/ref=dp_prsubs_1?pd_rd_i=B01FU5MVI8&psc=1
...How do you USE this information?
 
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...How do you USE this information?
A new battery will have cell voltage at 4.1V +.030V, -.005V. (Mine, with ~141k miles on the odometer, charge to ~4.059 V with .023V spread between high and low cells.)

In my experience, when the system switches to Charge Sustaining mode, the cells will have a voltage at ~3.5ish V. If one of the cells is consistently below that voltage, voila, there is a suspect cell. Keep an eye on it. If it gets worse, it’s time for remedial action at the dealer’s service department. Also, that cell may not hold the charge when the battery has been recharged.

Bear in mind that the data must be taken just at the point where the system switches from CD mode to CS mode. Similarly, data must be taken as soon as possible after unplugging the EVSE and starting the car.
 

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That would be correct, IMO, if you are playing a game of semantics. There has to be other Volts out there where the pack just flat out failed, one day, due to issues “other than battery degradation.” Most 3rd party warranty companies call this failure “excessive wear and tear” but don’t cover it. And of course, they deny the warranty even though we know it’s basically the same thing.
OK, let's arbitrarily double it. Now we are at less than 0.02% battery replacement due to complete failure or degradation. Still a very, very low number. Most would say insignificant, unless it happened to them. If the battery outright died before the warranty ended, it's a free replacement so not really an issue. Still, no one want to be one of the 0.01% with a complete failure or severe degradation after warranty expires.
 

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OK, let's arbitrarily double it. Now we are at less than 0.02% battery replacement due to complete failure or degradation. Still a very, very low number. Most would say insignificant, unless it happened to them. If the battery outright died before the warranty ended, it's a free replacement so not really an issue. Still, no one want to be one of the 0.01% with a complete failure or severe degradation after warranty expires.
However we don't actually have the data on the non-degradation related failures. Whether it's 1%, 5%, etc we don't know. A failure is a failure, regardless if it's within warranty or not. If the total number of failures is so insignificant, then GM should just publish the data as it would be in their best interest from a PR perspective.
 

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However we don't actually have the data on the non-degradation related failures. Whether it's 1%, 5%, etc we don't know. A failure is a failure, regardless if it's within warranty or not. If the total number of failures is so insignificant, then GM should just publish the data as it would be in their best interest from a PR perspective.
I don't think they want to because there must be a bunch of non-degradation related failures and they don't want to skew the numbers. The real number of battery failures HAS to be greater than 0.01%, common sense dictates that as time progresses batteries will wear out over time and fail. Whether or not they are actually considered "degradation," it doesn't matter - a dead car that can't be driven on the HV battery to me is a degraded battery, IMO.
 
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