Chevrolet Anticipates Up To 40 Percent Capacity Loss For 2017 Bolt EV Battery Over Eight Years20
Let’s preface this story with a disclosure: battery degradation is not anything new. As Autoblog points out in its report, the Nissan Leaf, Tesla Model S and other vehicles all suffer from loss of battery capacity.
But, according to the 2017 Chevrolet Bolt EV‘s owner’s manual, the brand is preparing owners to accept the fact their vehicles may lose up to 40 percent of its capacity over eight years. That equals out to 143 miles of range should the worst-case scenario come true.
Per the Bolt EV’s 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.
So, yes, in the year 2025, your new Bolt EV may not be chugging along to 238 miles of range. However, with the way battery and propulsion technology is moving, who knows what kind of solutions will be available to remedy the problem.
It is worth noting not one Chevrolet Volt battery has been replaced for degradation but were also talking about a full-fledged EV here rather than a PHEV.
- Sweepstakes Of The Month: Win a 2023 Corvette Z06 Convertible. Details here.
GM is only hedging their bet here as 40% is worst case where a customer may be charging it on the fastest settings every time and running it down to nothing on ever run.
Generally they will not be seeing this. All EV cars have the possibility of degrade under some use and charging conditions.
I think if you will get the rest of the manual it will offer the recommended conditions or actions to extend the life of the battery too.
Hedging bets is one thing, but asking owners to accept losses like these isn’t a viable strategy IMHO.
Nissan were confident that their battery technology was good, but real life taught them otherwise. Having seen the cost and disruption to Nissan’s EV program and the consumer backlash GM are understandably cautious. Despite all the testing LG and GM have done on these new batteries, they can’t be sure that real life won’t treat them well. As for guidelines on charging/driving behavior to extend battery life, that’s nice but no guarantee, LEAF drivers followed the guidelines and still had unacceptable loss of capacity.
I get the caution, but to offload all that risk onto the owner is really bad news for the Bolt program.
I would wager since I have yet to read the owners manual here yet but much like the Volt and other EV cars they will recommend the way to charge and use the batter to maximize the life of the battery that in most cases will degrade it 10%.
But like most other rechargeable batteries you can do a hell of a lot of damage if you do not follow the recommended practices and charge at a high speed often and also run them down farther than you should
We see it with cell phones, we see it with cameras, lap tops pads, drones and even other cars.
If there is a way to abuse something and even if you warn people they will still do it. With EV high rates of recharging takes away batter life as it has been a simple fact not only with nicad but also lithium.
Also factor in in 8 years the performance of a Bolt may be like driving a Model T as technology is growing at a fast rate. Just look a the smart phone. Would you want an 8 year old Samsung or I phone?
This car is a different game and I would say it will be shocking if more than 2% of all the Bolts see a decline of 40%. If they do see more I can see GM stepping in for public relations sake and either replacing them and or at least picking up a good part of the bill.
GM is wanting to grow this segment so they will go out of their way to make these cars a positive experience.
But with the warning it may help keep people better to the charging program that keeps the battery viable and it also give the right to refuse service in cases of where abuse are clear.
This is a slow growth segment and a segment that is not going to be profitable at the entry level for a while but with regulations by federal and even states like California they have to grow no matter if they like it or not.
This is just another the sky is falling deal where people are not understanding the whole deal before they pass judgment.
It is always better to under promise and over deliver. GM is going to see a decent number of these for being a EV but it will never be of the volume of a Cruze as if they are losing money there is an optimum number they would like to meet then move to a next gen that will be a better car and one that will draw closer to profits and higher volumes.
It is great GM provides this information (everyone else is afraid to). This is solely for planning purposes, if I have a 80 mile round trip commute, after 8 years the Bolt will still work for that with only home charging, even worst case. Even for extremely cold temps.
This degradation is exactly the reason why 200+ mile capacity batteries are necessary for EVs. As a customer I want to know what to expect, but I imagine most will be closer to 10 or 20% after 8 years/100,000.
Me? If I get one I will probably use the Hill Top mode so it doesn’t charge the battery fully (reserves it for Regen) to extend the life some.
If battery degredation to this degre affected *just* range I get yor point. However a battery that goes below 70% of original capacity is considered by most as being at end of life. This is becuase several other factors make the battery less useful.
1. Speed of recharging is compromised with a degraded battery due to higher resistance in the battery pack. Reduced range increases the likelihood you’ll need to recharge on the road, so slower recharging isn’t a welcome characteristic. Double trouble.
2. Regenerative braking effect is also compromised for the same reasons thereby reducing the car’s efficiency. Range is now compromised due to both lower overall capacity and due to poorer efficiency. This regenerative braking effect can decrease efficiency by 20%. Once again it’s double trouble.
You realize that GM is being forward and stating in front what they guarantee, this is not offloading risk to the consumer, it is protecting them (and clarifying what to expect). 70% is arbitrary.
It is true that internal resistance increases with age, but where are you going with your argument? Are you trying to argue that all EVs are bad?
Regen braking helps some in town, but it is always better to not use regen braking (since it isn’t 100% efficient) and avoid changing speeds instead. Not practical in the city, but regen braking mostly benefits highly aggressive drivers accelerating more than they need to.
Overall, the Bolt EV is showing figures of what I would expect for a BEV. Even if it loses 20% efficiency, it might go from 119 MPGe down to 95 MPGe, still plenty good (Similar to a new Tesla actually).
Where I am going with my argument is that worn out batteries need to be replaced. If GM are asking consumers to accept 40% degradation within the 100,000 mile warranty period, then the Bolt is bad. Not EV’s in general.
There is a service in LA that provides chauffeured rides to Las Vegas and back in a Tesla. The car put 200,000 miles on in just over one year. It lost 6% of its rated capacity. Tesla replaced the battery at no charge not because it was worn out but because the distance to empty gauge became unreliable and rather than ask their customer to wait for a free software fix, they swapped the battery. Compare that level of service to GM’s you need to be willing to accept 40% degradation in 100,000 miles.
Nissan have lost the confidence of their early adopters due to high unwarranted battery degradation. If the Bolt ends up with the same issues they will lose consumer confidence and future sales rapidly.
Failure to stand behind your product is not the same as saying EV’s are bad.
You realize Tesla provides no guarantee on capacity? Only electronic failures, and they will replace with a battery at least the same capacity as the worn unit? GM would have replaced that one too.
The referenced Model S chart doesn’t account for age (which causes capacity loss as much as cycling does). My guess is the Bolt EV will be comparable to the Tesla for loss. How many 8 year old model S cars are on the road to compare to?
This guy for example has lost 7% in 34k miles with his Tesla.
I imagine, based on past experience of LG in the Spark EV and Volt that the Bolt EV will do just fine. It has a much better thermal management system then the Leaf.
I like that GM puts a range as to what to expect so it can be planned for.
We can trade articles showing one car vs another car until the cows come home.
A study of several hundred Tesla is more instructive.
90% at 130,000 miles is typical for Tesla’s is the wild across hundreds of cars. You can see several outliers on the chart referred to below, so there will always be glowing or horror stories, but the average is pretty darned good.
I understand there is no warranty with Tesla for degradation. When I bought my 2011 LEAF I signed paperwork acknowledging no warranty for degradation. The difference between Tesla and the rest is they stand behind their product, swapping batteries as necessary without having to be sued into a retroactive warranty by their customers.
Based on Volt and Spark EV performance, I imagine the Bolt EV will be closer to the Tesla. That is of course speculation at this point, but Bolt EV and Spark EV have done well. Leaf skipped the liquid cooling which could pose a huge problem during quick charge or high ambient temps.
That seems about right, the active temperature management is a key factor.
Shame the same confidence in the technology isn’t reflected in the GM manual for the Bolt.
JP, to impact charge and regen rates internal resistance doesn’t just have to rise but rise enough to impact the charge rates due to either pack or cell voltage approaching a threshold. Household L2 charging will never see a degradation because if it did the vehicle would be unable to move itself up hills and the likes long before that happens. At the peak 80kW DC charge rate, that is only about 1.25C, which is nothing for this battery chemistry. Consider a Spark at 50kW easily accepts charge at about 4.5C. So, I’d say that the only thing the car will see is a loss of capacity if, and only if, it degrades passed the buffer SOC we all use in our vehicles to protect against capacity driven performance loss with some wiggle room for resistance based consumption increases . That buffer, BTW, is likely a big part of why no Volt packs have yet to be replaced. There is room for degradation built into the system on purpose.
That’s all well and good on paper.
I’m speaking from experience with a LEAF. Rapid charging when in good shape took 18 minutes to 80%. With a 45% worn battery it took 35 minutes. Note that 35 minutes to add almost half the amount of electricity. That’s a steep price to pay. So really it was 4 times slower.
All we can do is napkin calculations for the Bolt since there is no real world experience we have access to.
With a heavily degraded battery regen and charge rates will suffer. How much? We’ll see.
This might explain why the GM numbers for 80 kw charging seem so low, maybe they account for worst case degradation? They claim 30 minutes for 90 miles which is closer to 40 kw average. My bet is after some degradation that would be about right.
Yes. EV Manufacturers tend to cite worst case scenarios for charging EV’s. I have no idea why. EV manufacturers are more than happy to cite “typical” driving range for their vehicles, not worst case.
Potential buyers fret over recharging times as well as driving range.
The inconsistency in how range and recharge times are cited has always puzzled me.
Should this be a surprise to anyone who has owned a modern cell phone for more than a year ?. Electric cars for this very reason aren’t viable. I really don’t see why anyone would buy one.
Your car has a battery. Might as well write the whole thing off too because the battery is only good for 2 years, right?
You can replace a “car battery” for $50-200. It is an insignificant cost when factored over 2 (realistically 3-4) years. OTOH, replacing a $5500-20,000 battery, even after 8 years, amounts to a significant expenditure.
The high voltage battery should last the life of the car, so same as replacing engine or something.
Who keeps a car for 8 years anyway?