Fortunately...Battery degradation has not been a significant issue with the Volt. (Unlike the Nissan Leaf.) Most Volt owners, dating back to 2011 models, have not been reporting significant battery degradation due to the Volt's extremely conservative battery management system.

As far as battery degradation goes... Nobody has really owned a Volt long enough to know. So far it seems likely you will get 10-15 years out of the battery before your range significantly drops.

 

I'm not that worried about it, I'm just curious if the 30% is off the total capacity or the usable capacity.

 

Here is someone who asked the same question. Don't know if it helps.

http://gm-volt.com/forum/archive/index.php/t-10885.html

I suspect that there is some discretion involved. If your dealer and your Volt advisor know you are unhappy with the range... It will probably be replaced or upgraded. However... We have not heard of many Volt owners complaining about reduced capacity.

I recently changed my tire brand and had the short air dam installed. It reduced my range by 2-3 miles average. But the battery charge capacity is about the the same after 2 1/2 years.

 

I think that this question is a lot like the question about "fueling cost":

Most of us went into agonizingly detailed fueling cost analysis before we bought our Volts, somehow convincing ourselves that the volt had to "pay back" some exactingly defined "excess" cost.

After driving our Volt's for a while, we realize that that exercise was a waste of time. If I pull up to a friend's house in a convertible BMW or on a hog, no one asks me if it "paid back". why is this an issue for the Volt?, The Volt ended up costing me less than the cars I was comparing it to, it drives and handles just as well, perhaps lacking a bit of interior refinement and size compared to those cars, but "payback" should have had nothing to do with it.
Similarly the "battery replacement cost" issue is a red herring, (to get back to my point!):
In a BEV, potential battery replacement cost is an issue, because a 60% BEV range is a problem (remember that's "true range" not maximum range) but in an EREV, (PiP, Energi, Volt) an eventual loss of 40% of battery range, after 12 or 15 years, is not a big deal, the car just keeps going anyway, and when the car has 200,000 miles on it and is 12 years old, I'm far more likely to be willing to put an extra 10 gallons of gas into it every month than I will be to spend $2995 for a battery and $1500 for the labor to replace it....

so my bottom line is that the correct response is:
It doesn't matter- battery range degradation will NEVER matter in a volt.

 

My take is it would be on the useable battery range. If I used to get 45-50 in the summer and now at year 8 or 100k miles I can only get 24-30, that's a problem.

 

Since the standard for batteries is that they reach EOL (end of life) when they lose 20% of capacity that would have to be usable. Also note the manual says "up to". This strikes me as CYA language. I wouldn't think of 30% degradation as normal, especially since the same battery is warranted for 10 years and 150K miles in CARB states.

 

There's a video somewhere of Andrew Farrah saying to expect a 10-30% loss of the usable range. Remember, the usable window shrinks as the total battery capacity shrinks.

 

To loose 20-30% of usable range means you've lost 55% of total capacity. At that point the battery is dying very quickly if it is anything like a laptop battery.

 

If you assume the Volt maintains a usable window of about 65% of total battery capacity, the quoted statement is not true. A loss of 20%-30% usable capacity results in a 20%-30% of total capacity. So effectively it does not matter which number you work with for the warranty the loss in terms of percent are the same.

Keep in mind, warranty periods, by design, are set to be significantly shorter than the typical life of the product, otherwise companies would go broke replacing everything they sell under warranty. For example, currently solar panel warranties are generally 80% or better after 25 years, but real world looks like most solar panels will last about 40 years at 80%. So a battery with an 8 year warranty at 70% or better should outperform this in the majority of cases.

 

I'm hoping that in 8-10 years, someone (some aftermarket service) will be able to rebuild Volt batteries with much higher capacity cells and reprogram the car to utilize them.

Heck, if I keep the car long enough for the battery warranty to expire, I'd want to see if there would be a way to open up more of it's capacity. I'd like to increase it to 80% of total capacity if not a bit more. I find in my current driving scenarios, most of the time when I hit the engine, I could have avoided it with maybe 2-3kWh more 'usable' energy.

 

Yes FrayAdjacent, I'm totally with you there. Once the battery is out of warranty, why not at least open it up to the same SOC level as the ELR which is 72% vs the 65% for the Volt. They have been really over-conservative when it comes to the Volt battery. If the 72% is good enough for the ELR, why not the Volt?

I'm at 54K EV miles. I will be out of warranty in less than 2.5 years. I'm maximizing my battery warranty by having virtually no gasoline miles with 139 gas miles to date.