Could Chevy Bolt EV Lose 40% Of Its Range In Only 8 Years? Owner’s Manual Raises Questions


While it’s very likely to simply be a matter of the company looking to protect itself from potential lawsuits down the road, the Chevy Bolt EV owner’s manual section on battery degradation and range loss raises some interesting questions.

The owner’s manual (page 322) states that the battery pack capacity could degrade by as much as 40% over the 8-year warranty period. Or by as little as 10% over that same time period. It certainly sounds like this is just a matter of the company protecting itself from being sued, but also seems worth highlighting.

Here’s the full section from the owner’s manual: “Like all batteries, the amount of energy that the high voltage ‘propulsion’ battery can store will decrease with time and miles driven. Depending on use, the battery may degrade as little as 10% to as much as 40% of capacity over the warranty period. If there are questions pertaining to battery capacity, a dealer service technician could determine if the vehicle is within parameters.”

While that figure isn’t likely to relate to many (or probably even more than a few) owners, a 40% decrease would result in quite a dent to the model’s range — from 238 miles per full charge down to ~143 miles. Obviously, battery packs can always be replaced, but that would still be quite a drop, and something to think about if eventual resale is a consideration.

Autoblog notes in its coverage that “since the Bolt EV is the one that GM wants to promote to a much wider audience than the typical EV buyer — we have to wonder if this sort of range decrease will be acceptable to the masses.”

A good point. While I understand the need to cover oneself from lawsuits, the phrasing in the owner’s manual is likely to lead to some people interpreting this as a sign that the Bolt EV battery will degrade rapidly. Going by the way that Chevy Volt plug-in hybrid battery packs have held up to date, though, this is unlikely to be true.

6 thoughts on “Could Chevy Bolt EV Lose 40% Of Its Range In Only 8 Years? Owner’s Manual Raises Questions

  1. I don’t see the problem. The 8 year warranty is good news.
    I would be more interested to know at what level the warranty kicks in.

    1. Warranty on EV batteries are as to manufacturing defects not as to degradation. If a Chevy Cruze manual indicated possible transmission failure by 100,000 miles, would people buy the car?

  2. There are a million trade offs that engineers and integrators make when designing a battery system. They can choose to make a system that gets a seemingly impossible range given the battery factory spec (compared to more conservative OEMs like Tesla). But they are trading off things. Longevity may be among the trade offs.

    Exploding hoverboards and Notes are an extreme example. With BEVs it’s ALL about the wisdom of integration and engineering.

    1. Note sure what the chemistry used in the new bolt lithium batteries. However the Chevrolet Volt batteries I have not seen noticeably degraded mileage. If I’m light footed. I get 40 to 42 in the summer with air AC and know ac running and stop and go traffic On the BWI parkway , I’ve gotten as high as 53 mi going 25 to 35mi per hour. Though in winter at 20f degrees running the heater 27 miles, everyone forgets how much heat it required to heat the cabin , and all that being said, the ice engines used to idle and heat the car up! Vs using your house plug o heat up the car helps as well, so it will be interesting to see other people examples, I know the regen on both the 2017 Volt puts out more Kw then the 1st gen Volt, one we see the Chevrolet Bolt , I heard even more kw regent then the 2nd gen Volt , so I believe most people will be presently surprised, considering Chevrolet is realeasing the car in the winter, so will see improvements in the EMPG , note with drivers keeping there electric cars in the garage do not experience as must winter effect as I see due to that I don’t have a garage!

  3. This news item will come up when EV-noobs do searches. I fear the wording of the headline will invoke misunderstandings more than help them understand about EVs.

    At the beginning, growing up in the late 1950’s, we neighborhood boys would get our first manhood training by hanging out with the men working under the hood of their gas-car (ice, – there were no production EVs back then).Those days of getting stinky, smelly when being with your Dad as he changed the oil was a part of growing up. It was fairly common to think one’s car ownership would be for 8 years (ice were built inefficiently heavy like a WWII tank back then).

    But the length one keeps a car depends on the person, and other factors. My Father kept his car for 8 years but the times were very different back then (there were no cars made for the public during WWII, so you learned to make them last, etc.).

    My Mother went through cars often. Not new ones, but a different car about every two years (almost as often as like the way she went through different purses, clothing, etc.). Her cars did not die, she just ‘felt’ she needed change.

    Someone who bought a ‘new’ washing machine way back then would expect it to last even after the kids had grown. That type of thinking where you pay a lot up front and then get it all back with a long life was fairly typical (and still around in some of the more stodgy regions – old thinking dies hard).

    That 8 year figure may not relate to today, depending on what you are talking about. A washing machine search gives:
    ‘most washing machines will last for approximately 7 years’

    A car search gives:
    ‘drivers keep a new vehicle is 71.4 months — around 6 years’

    A phone search gives:
    ‘an average of a year and a half’

    But know that some might change their phone for the new OS and or features, or for a new higher capacity battery (or bragging rights). Cars today (and washing machines too) have a lot more technology built in (maybe more than we need, but it sells product, moves metal, etc.).

    So today, it isn’t that the car died is the life of ownership. It may be that technology or their family’s needs have moved on (changed).
    So, like the fast turn around in phone sales, cars today will also see buyers doing an upgrade, and not because the pack it dying.

    Battery pack life as described, and commented on, also varies:
    -does the EV’s pack have a good thermal control design (is it designed to keep the pack cool in summer and warm in winter?).

    Looking at the Leaf EV’s original thermal designs and in hot parts of the U.S., caused some pre-aging of the pack (it lost capacity before it should have). Other EVs with good thermal designs do not have that pre-aging issue.

    How much care did the owner take to baby their EV. We all know abuse of a ice shortens its engine, transmission, and more. Some of that also applies to EVs:
    -Did the owner do an excessive amount of L3 DC (quick) charging without also doing some slow charging to re-balance the pack and its guessometer, etc.

    Only time will tell if the Bolt’s pack design will have a life shorter than a Leaf, or longer than a Tesla-3.

    For EV-noobs, when buying an EV, I recommend you only select the model that have at least a 6kW on-board L2 (level-2 j1772) charger, and also have a L3 DC charging ability. When buying a used EV, they will need to go to the seller, have the EV fully charged, and see how many miles it states it has as range (if it is a Leaf how may bars does it show, etc.). That will give you a feel of how healthy that used pack is.

    Lastly, different than when buying a used ice, replacing a pack essentially gives you a new car. But with an old ice, a new engine is good but you may have a worn out transmission, differential, etc. (EVs do not have those). So one could consider adding the low cost of an EV with a tired pack + the cost of replacing the pack and compare that to a higher priced EV with a healthier pack (do the math).
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