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There's an interesting discussion in the comments section of this article:

http://www.hybridcars.com/zero-battery-degradation-replacements-giving-chevy-volts-an-edge/

The idea is that our batteries are really degrading but we can't notice it because software is adjusting its algorithms with age and using more of the battery's real capacity as it degrades. They left a cushion that will take the hit first before we really notice this degradation.

I'm interested in hearing the opinions of some of the experts on this forum, is this really true?

Here are some quotes:

"Because the Volt doesn't fully use the battery, Chevy can likely have software that adjusts the "max" capacity of the battery when the battery starts degrading so to the consumer, it doesn't look like the battery is degrading because they're still getting the full charge that they normally expect.
The Volt doesn't use some "magical" battery technology that doesn't degrade. By its very nature, every type of rechargeable battery degrades over time. Chevy just has the option to hide it when it's happening."

"t's not a theory, it's well know how the Volt/Prius/etc hide the battery capacity because they only charge to 80%. That means you can have 20% capacity loss and you'll never know the difference. There are owners of hybrids that have battery replaced due to capacity issues, you just don't hear about them that much since they can use gas to cover issue up."

"Let's say the capacity of the Volt's battery is 100 units of energy. When you plug the car in and charge it fully, the car tells you the battery is fully charged, but in reality it has just charged it with 80 units. 80 units is the advertised battery capacity, so everyone is happy.
Now, over time, the battery does degrade (slowly, because of the active temperature maintenance). Years later, the actual capacity might be 81 units, but the car still charges to 80 units and everyone is still happy because the battery is performing exactly like it did when it was new."
 

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Someone would have noticed by now with a diagnostic. Also, some batteries would have degraded enough to start reporting diminished capacity. This conspiracy theory is a candidate for snopes.

Newer builds such as ELR use the exact same battery with greater useable capacity. However, none of those have failed either.
 

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It's not so much hiding as a consequence of limiting the max state of charge. In general the performance of batteries doesn't change much with degradation, so you won't notice as long as degradation is less than the upper restricted part. But, limiting the max state of charge itself limits degradation. That's part of the reason that Prius batteries have been reliable almost everywhere. So, really, you don't notice degradation because there really isn't much degradation.

GM took a conservative approach, but has gradually been pushing up the maximum state of charge as they have become more confident of stability. But, aside from the ELR, every time GM has upped the max SoC, they've also increased battery capacity, which means that they've kept the percentage increase down.

The battery also has a TMS, which is a key factor in limiting degradation, and the charging rate is low, with only regen and mountain mode, limited use cases, pushing the rate high.
 

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Of course G.M. is not deceiving us. G.M. reported out that there have been zero battery pack replacements due to battery degradation (not that there has been zero degradation). Nissan cannot make this claim about the Leaf.

The rate of actual degradation is discussed in this post which cites testing performed by the Idaho National Laboratory:
http://gm-volt.com/forum/showthread.php?240322-Idaho-National-Laboratory-publishes-Gen1-Battery-Pack-Laboratory-End-of-Test-Results&p=3356418#post3356418

Following this established metric, we could roughly calculate our Volts should experience 25% capacity loss occuring at 25 / .0000726 = @350k miles and would this mean it is possible the battery pack in our Gen1 Volts will only be able to get 50% or half their original range clear out at an amazing @650k miles 50 / .0000726 = 688,705 miles
In my case, this means that after driving the car every day for 15 to 20 years, the electric range on my 2012 Volt will have dropped from 38 miles to 30 miles. Pretty great.
 

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Batteries are like tires. Putting miles on tires gradually wears them out. Same thing for Amp-hour throughput on batteries. Every battery ever built, in the past, present, or future, will start wearing out with its first Ah. People need to get over it. Batteries, like tires, are still extraordinary useful.

The fact that GM does not use the full capacity of the Volt's battery results in no noticeable loss of EV miles, at least for the first several years. This is not "deception," this is GM providing a quality product. My 2011 and 2014 Volts have been the best cars I have ever owned, by far. A durable, dependable, battery design is part of that positive experience.

GSP
 

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While I understand the OP's point, I'm not sure it really matters. In my case I bought a car with the understanding that it would be capable of "X" miles on an electric charge. If the capability stays at "X" then I know what to plan for and I feel that I got my money's worth regardless of the method by which "X" miles is achieved. (and BTW, a lot of laptops do precisely the same thing).

It's sort of like how most fuel gauges don't immediately start counting down after you fill your car because consumers started complaining that their car never registered "full" so auto manufacturers re-mapped the gauges to hoover at "F" for a bit before they started dropping down. Auto manufacturers have always had to play with things like this in order to satisfy public perceptions and expectations.

As long as I can make my work commute that's good enough for me.
 

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http://www.androidauthority.com/interview-chevrolet-volt-battery-619915/

Andrew Farah, the Volt's chief engineer, stated that the Gen 2 Volt's battery could take 6,000 full charge cycles before showing any kind of significant degradation (statistically significance, mind you, which is a lot smaller than what most people would think "significant" means).

To put that into context, if you fully discharged and re-charged the battery every day, 365 days a year, it would take *16* years of driving to observe any kind of significant degradation. The Gen 2 Volt's battery has a higher depth of discharge than the Gen 1 (~75% versus 65%).

If any degradation hiding via buffer tricks was going on, I would think it would surface much earlier that *16* years.
 

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I think it has always been obvious that the charge cushion would mask degeneration. Chevy never deceived anyone about that. They made the cushion information fully available from the beginning. Anyone who thought the battery would never degrade was just naive and has apparently never owned a rechargeable device like a cell phone. The claim made in the article holds the same logic as claiming that their Dodge Charger is deceptively hiding the fact that the engine is slowly wearing out over the course of a couple hundred thousand miles by providing an abundance of horsepower that masks the effect.

IMO, chevy was basically forced to design the charging parameters this way by government regulations in California that require Chevy to warranty the battery for 150,000 miles. When have you ever before heard of anything in a car warrantied that long?
 

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When have you ever before heard of anything in a car warrantied that long?
Nothing surprises me about the Republic of Kalifornia. :p
 

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IMO, chevy was basically forced to design the charging parameters this way by government regulations in California that require Chevy to warranty the battery for 150,000 miles. When have you ever before heard of anything in a car warrantied that long?
Chevrolet could have purchased ZEV credits instead...

Strictly, the warranty is on the emissions control system, which has to be 15 years, or 10 for a storage device. The idea is to make sure that these things are working for the life of the car, so that they can have long-term benefit. Having a warranty means that it either has to last, or it has to be very cheap to replace. It's always worth remembering that the ZEV mandate is there because most of the products on sale are known to be harmful.
 

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this thread could have been started back in 2008, given the original post. People refuse to believe the reality of modern lithium battery chemistry: a cell cycled through its full range, typically from 3.0 volts to 4.2 volts, will typically get 1000 charge cycles down to the 80% of its capacity threshold, That is if the first cycle from 4.2 volts to 3.0 volts provide 10 watt hours of energy, the 1000th cycle will provide 8 watt hours. But that same cell, cycled instead from 3.1 volts to 4.2 volts will have a 10,000 cycle life to 80%: that is, if it provides 9 watt-hours at its first cycle from 4.1 to 3.1 volts, then at 10,000 cycles it will provide 7.2 watt hours. after 10,000 cycles. (this is example information only, the volt's cells have different threshold levels)

Besides - in the volt it doesn't matter- Right now, with 58,500 miles on my 3 year old volt, I get 30-35 highway electric miles with the AC running before it switches over. (45 around town) If in 6 more years, with 160,000 miles on my then 9 year old volt, I am instead only getting 20-25 miles on that charge before it switches over, I'm still better off than I would be in any 9 year old BEV or in a lesser plug in car. I'm not going to replace the battery then, because I don't need to... I can drive without any charge at all!!!.. I have seen no evidence of degradation in my battery, but it doesn't matter- even when it does finally degrade, I will still get more electric miles than I would in any other 2013 plug-in hybrid when it was brand new...
 

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Chevrolet could have purchased ZEV credits instead...

Strictly, the warranty is on the emissions control system, which has to be 15 years, or 10 for a storage device. The idea is to make sure that these things are working for the life of the car, so that they can have long-term benefit. Having a warranty means that it either has to last, or it has to be very cheap to replace. It's always worth remembering that the ZEV mandate is there because most of the products on sale are known to be harmful.
Those long warranties for emission controls are based on manufacturers trying to cheat. So VW at one time found their cat convertors wouldnt work well past 30k and the cars failed emissions. So rather than redesign the emission controls, they just called for a maintenance replacement of the cat at 30k, costing about 1k. That is what a lot of the OEMs did. any part not going the distance became maintenance items, often very expensive. Often ignored by the owner. The way to stop this was to make the so-called maintenance pieces part of the warranty.
 

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... I'm interested in hearing the opinions of some of the experts on this forum, is this really true?

Here are some quotes:

"Because the Volt doesn't fully use the battery, Chevy can likely have software that adjusts the "max" capacity of the battery when the battery starts degrading so to the consumer, it doesn't look like the battery is degrading because they're still getting the full charge that they normally expect.
The Volt doesn't use some "magical" battery technology that doesn't degrade. By its very nature, every type of rechargeable battery degrades over time. Chevy just has the option to hide it when it's happening."

"t's not a theory, it's well know how the Volt/Prius/etc hide the battery capacity because they only charge to 80%. That means you can have 20% capacity loss and you'll never know the difference. There are owners of hybrids that have battery replaced due to capacity issues, you just don't hear about them that much since they can use gas to cover issue up."

"Let's say the capacity of the Volt's battery is 100 units of energy. When you plug the car in and charge it fully, the car tells you the battery is fully charged, but in reality it has just charged it with 80 units. 80 units is the advertised battery capacity, so everyone is happy.
Now, over time, the battery does degrade (slowly, because of the active temperature maintenance). Years later, the actual capacity might be 81 units, but the car still charges to 80 units and everyone is still happy because the battery is performing exactly like it did when it was new."
None of the above are true. Why ? Here is what I understand about the Volt battery:
- the battery charge never goes bellow 20 % and never goes up of 90% which lets you roughly 70% usable power.
- the cells of the battery are all charged or depleted as a whole (within the limits 20-90%) so any degradation will be surely seen, because then the cells would be charged 20-85% or 15 - 85% or whatever.
- but because the battery is never totally discharged and never fully charged, the degradation is very slow. It has nothing to do with the "buffer" being used before any degradation shows up.
 

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GM has officially stated that they do NOT widen the SoC to mask degradation. But of course there is still some degradation... if you read your warranty, IIRC you are allowed up to 20% degradation before a warranty claim can be made. So at 80k miles, if your gen1 went from 38 miles AER to less than 30, then you might have a case. All the press release is saying is that they haven't had any like that. It's a certainty that there are early / high mileage Volts with measurable (a few miles) degradation, but they just haven't hit 20%. Or if they have, they are out of warranty anyway. But we all know they designed it well (thermal management, SoC limits) to minimize the degradation, unlike Nissan.
 

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In my mind this thread is just a bunch of arm flailing by a mental midget that doesn't like being wrong.
He figures he has a something to prove na, nah na na nah.


My volts range and capacity have slowly grown, from about 10.2 on the guess o metter and 42 miles range to nearly 60 all summer long and 10.4-10.8.

I had never seen more than 10.3 for a long long time until relatively recently.

The amount of capacity loss on a volt is so small that it is laughable to be worried about, we aren't driving a leaf that looses 50% of its battery capacity in 120,000 miles.
 

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Living here in Oregon our 2016 Volt is covered with a 150,000 mile battery warranty because we are a C.A.R.B. State;, California Air Research Board, standards. So is our 2010 Prius, which is pretty close now to that 150,000 mile figure. Just to let those who want to know, know, our Prius still appears to have no battery degradation since we purchased new in May 2009, also still has the factory 12 volt battery which is still functions like new.

I believe the weather here in Northwestern Oregon is responsible. Temps seldom get above 80 degrees in summer or under 30 degrees winter, during the year. Some days temp may only fluctuate 5 degrees or so from the low to high.
 

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Chevy isn't hiding battery degradation, they designed the car to accommodate known battery behavior. Owners will not experience loss in driving range over the design life of the vehicle. Pretty smart design if you ask me.
 

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There's an interesting discussion in the comments section of this article:

http://www.hybridcars.com/zero-battery-degradation-replacements-giving-chevy-volts-an-edge/

The idea is that our batteries are really degrading but we can't notice it because software is adjusting its algorithms with age and using more of the battery's real capacity as it degrades. They left a cushion that will take the hit first before we really notice this degradation.

I'm interested in hearing the opinions of some of the experts on this forum, is this really true?

Here are some quotes:

"Because the Volt doesn't fully use the battery, Chevy can likely have software that adjusts the "max" capacity of the battery when the battery starts degrading so to the consumer, it doesn't look like the battery is degrading because they're still getting the full charge that they normally expect."

GM has officially stated that they do NOT widen the SoC to mask degradation...
This has been rehashed in the past:
http://gm-volt.com/forum/showthread.php?39489-Only-getting-about-9.6kWh-from-a-charge-with-18°C-outside-and-battery-at-24°C&p=597881#post597881
 
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