This Chevrolet Bolt Battery Lost 8% Capacity At 70,000 Miles

NOV 6 2018 BY MARK KANE 55

Chevrolet Bolt EV battery seems to be okay, but perhaps not as robust as one would hope.

All batteries lose capacity over time and use, but the rate of battery degradation becomes less important in long-range EVs.

It seems that’s the case for the Chevrolet Bolt EV, which with its 60-kWh battery, is rated for 238 miles (383 km) EPA. According to News Coulomb’s in-depth analysis after 70,000 miles (112,000 km), its Bolt EV now only has 92% of initial capacity/range. The 8% fade is worth 15-20 miles of range.

The value of the 8% drop is not precise, but rather estimated based on energy consumed while charging, and at least partially could be the result of a software update done by GM during one of the recall actions. Other factors could be specific driving profile with a lot of DC fast charging.

Regardless, it seems that even after 150,000 miles, the Bolt EV should be able to go 200 miles (320 km) on a charge, which is swell considering that the first-generation EVs (aka Nissan LEAF) were struggling to go 100 miles when new.

“After 70,000 miles, I decided to review the data that I have gathered for nearly two years of driving the Bolt EV. Based on my estimates, my Bolt EV has lost a noticeable amount of battery capacity. To estimate the amount of degradation, I compared kWh used versus the battery percentage displayed at the station, and I was able to create a timeline of total estimated battery capacity.

0:47 Methodology

3:41 Degradation

4:44 Software Update affected capacity?

7:45 What can other EV owners expect?

9:30 Does DC fast charging contribute?

10:35 Does that much degradation actually matter?

13:03 My Recommendations

15:04 Closing”

Categories: Chevrolet

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55 Comments on "This Chevrolet Bolt Battery Lost 8% Capacity At 70,000 Miles"

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I assume hes fast charging once or twice a week at least?

He is using fast chargers fairly frequently and doing relatively deep discharges. So this might not be worst case but it isn’t normal driving. Most people will do fewer miles per year and use fast chargers less while discharging the battery less aggressively, so they will probably have less loss when they get to 70k miles.
His 70,000+ miles in just under 2 years is almost 3 times the amount of miles an average driver would have put on the car.
(13k miles per year is average).

LiIon degrade just by sitting. It’s not clear how much of his degradation was due to charge cycles or time. If much of his degradation was due to time, people may find less capacity at 70K miles even if that’s after 7 years.

I think this is why he’s asking for data from other people. If other Bolts with fewer (or more!) miles at same number of time has similar degradation, that would point to more time related degradation.

I understand that different pack chemistries degrade due to time while others tend to degrade due to high rates of charging and discharging. I have a Volt and I haven’t seen any degradation in my LG Chem pack in 5+ years but that is in part due to the relatively conservative use of pack capacity. From what I have heard, Bolt LG Chem packs are impacted/degraded by relatively high rates of DC fast charging, but not unduly so. I don’t think the Bolt has been around long enough for people to see much in the way of battery capacity degradation over time. Some, but not a lot.
It seems like this Bolt has just been driving more, and fast charging more, than a typical Bolt. So if we are seeing 8% loss in less than 2 years the likely culprit is DC fast charging and relatively frequent deep discharging.
Just my two cents.

I doubt it’s much to do with DCFC. Remember, Bolt DCFC rate is under 1C (about 0.5C at 55%). If that rate causes significant degradation, the battery is even worse than what’s in Nissan Crap (aka Leaf). Given that SparkEV with 2.6C charging did so well (10% loss after about 100K miles equivalent on Bolt), I suspect GM engineers picked the chemistry that wouldn’t be so affected by DCFC.

Far more likely, if it is an issue, is that NC regularly drive down to practically empty. I saw one video of him driving in middle of nowhere DCFC when he only less than 10 miles charge remaining.

No link to the source?

It’s the video itself :).

lol thanks.. didn’t realize the picture at the top is actually a video.. was looking for a link

GM went cheap with the interior and the suspension.
I’m just hoping this report is not another confirmation of how GM has build this car.
Hopefully, future cars will have this resolved.

Didn’t Tesla have a Battery Consortium that solved Battery Degradation?
Was not the solution, a literal solution, released to All Members of the Consortium?

“Didn’t Tesla have a Battery Consortium that solved Battery Degradation?
Was not the solution, a literal solution, released to All Members of the Consortium?”

That is got to be the dumbest comment ever by a Tesla fan boi on inside EV this year…

I thought he’s i3 fan boi?

Either way it’s dumb fanboy stuff.

I am just over 30k over 1.5 years and I estimate that I am down a little, 1-3kw. Hard to tell with how gm reports capacity. But looking at how much I use and how much is left, the capacity is not 60 anymore.

You can increase your lifespan, try to use it daly in the 20-80% charge range and save those 100% charges for those long trips out of town. Enjoy your Bolt Excellent news.

Seems perfectly normal and aligned with expectations.
Bjorn got 3% on the model X after 21.8k miles, 6% after 46.6k miles, if we try to deduce the value for 70k miles it will be around 8%.

I don’t think it’s terrible, but makers should announce car life average range and not just “shining new” range.

there is a difference tho .. Bjorn really is fast charging his P90D while a Bolt, at under 50kW, is just “fast charging”

I have 52K on my 3.5 year old model S 70D and am showing 225 miles from the original 240. This is 6% which seems similar to the Bolt’s degradation after 70K and the Model X after 46.6K miles.

my take is exclusively on the “fast charging” Bolt part of the argument .. I don’t disagree with the lost % of any car

Just for the clarification…
I am a subscriber to the News Coulomb channel.

News Coulomb is driving long distances for work in California on daily basis.
1. He is using DC fast chargers for that.
2. He is depleting battery almost to 0% and charging back to 100% due to his long distance rides and not enough chargers on the way.

Though regular folks, i.e. 95% of EV drivers, are charging at home with level 2 chargers.
In such scenario, the battery degradation is almost nonexistent.

This article shall provide these additional details.

He has abused his battery about as much as a “normal” person could during normal driving. Despite the hard usage, his battery has only degraded ~8% (heavy fast charging, charging to 100%, depleting to near 0).
Also, a battery recall update may account for half of the observed degradation, as GM may have reduced the total usable capacity of the battery on the low end. So the real world did may have actually only been 3-4%.

Anyone that has put 70,000+ miles on a BEV in just under 2 years is probably close to the ‘worst case’ scenario for battery longevity. Losing just 8% under those conditions is pretty impressive.
35,000 miles a year is almost 3,000 a month, or around 100 a day.

I often see his video en route to Las Vegas. That might explain so many miles. He must have good investment strategy.

In terms of charge cycles, my SparkEV with 30K miles had almost 100K miles worth with Bolt due to SparkEV being less than 1/3 battery and 2.6C DCFC vs Bolt’s under 1C. Yet the degradation was only about 10% after 3 years.

“Heavy fast charging” is laughable. Bolt’s DCFC is less than 1C, slower than any EV on market today. That is the most gentle “fast charging” of any EV in history.

Faster charging equals less battery life, Gm claims the battery degrades much quicker when the battery is not kept in the 70 degree range. That’s why, when the car is plugged in GM runs heaters and coolers to keep it at this constant temperature.

I can’t help to think maybe cell geometry has something to do with this. The pouch type or prismatic cells are larger and more difficult for temperature control. Also for those who have EV’s and put alot of miles on them, it’s probably best to get one with the biggest battery possible so you can do 300+ miles on charge. Unfortunately the only real option is Tesla and they took away the Model 3 LR RWD.

Presenters … is your outfit more important than the content of your presentation? In other words, if you’re trying to do a serious, important and informative presentation … don’t wear a hat that reminds your audience of the medieval court jester. It detracts from what otherwise might be a good presentation. This is pain and tedious. And goofy. This guy blew a tire his first week of ownership after driving over a pothole. He thought his Bolt was an SUV, got stranded. Keep this in mind. This is grandstanding at its best.

News Coulomb wears many hats – this one is the “The-Guy-Who-Wears-An-Orange-Hat” hat, so what.

What, you want everyone to wear a clown suit when presenting? Get with the program. It’s not 1984 anymore. I personally like the hat. It has that “South Park” vibe.

Eh? The guy reports on his experiences with his Bolt. I think he’s doing it mostly to increase awareness of EVs. I’m not sure what’s grandstanding about it? I doubt he makes much of anything off of his videos, whether measured in time or notoriety.

This seems like a pretty aggressive use profile for the car so I bet most people would see less over a similar mileage.

Hilltop Reserve and less DC charging should give the Bolt batteries a very long life.

Solid results considering the abuse the battery took over this short time frame.

You have to consider how long people hold onto a car. A lot of people keep their cars to 100,000 miles before they’re bored, or attracted to a newer model, or just “feel” they’re unreliable. Some push to 150,000. You’re in pretty rarefied air if you keep your cars to 200,000 miles.

Yet at 200,000 miles, you’d still have over 75% of original capacity, which is to say 160 miles or so. 160 miles meets the daily needs of 99% of the population.

There’s no issue here in a practical sense. If your life depends on getting 238 miles out of the Bolt between charges, then you’re looking at the wrong car for your needs.

Yank the battery and use it for stationary storage at 200k. Throw in a new battery and go another 200k miles.

Currently, to purchase 45 kWh of lithium batteries for storage, say from battle born, costs approx $35,000. It would be nice to used salvaged packs from EV’s.

I have an MY2012 Chevy Volt that is garaged year round and has 72,000 total miles with about 50,000 AER. Had to take it to the dealership for lost propulsion error after driving long distances and parking in the summer heat for an hour or more. The dealership adjusted the available battery to correct the error. I went out of my way to find out the current SOC of the battery. It was at 91% or 9% loss.

My 2013 Volt has 71,000 miles total and about 49,000 miles AER. Still get like-new 10.2-10.5 kWh and 35-40 miles range before depletion except during winter. And it is ungaraged year-round in Redding, with summer mid-day temps averaging over 100 deg. and spiking at over 110 deg F.

It seems his driving style will return the fewest life cycles possible.

Good to see so little degradation in an abused battery. And I’d bet a trivial amount of money that Bolts perform like this, overall, although I wouldn’t base a car purchase on it.

I urge everyone here to remember that a single observation isn’t data, it’s an anecdote. Don’t leap to conclusions based on so little information, or you’ll wind up making some wildly wrong decisions.

Interesting. Much higher than I would have expected given the cooling system and large capacity (meaning shallower DoD and less cycles). At the same point in mileage, I had lost ~14% in my 2014 Leaf. I’m now at 107,500 miles (172,000km) with ~20% degradation.

20% seems quite severe at just iver 100,000 miles.

Do you consider your personal charging habits average or do you DC fast charge a lot? Do you run the pack down below 5% often and charge to 100%?

I’m very interested in this subject and how It plays out for different users of the same car, and also the climates they drive in.

Remember Leaf doesn’t have a very big battery. That’s a lot more charging cycles on the Leaf than it would be on a Bolt or Tesla. On top of that the Leaf battery is fairly notorious for battery degredation.

“meaning shallower DoD ”

That isn’t the use case here. 70K miles in 2 years means a lot of deep cycling.

I believe the temperature managed batteries settle at around 92-96 percent, at 107k miles they should still be at roughly this 8 percent degredation level. The degredation chart looks steep at first and then goes flat when it hits the sweet spot, probably staying around that level for 250k miles. At least I think that’s how the Tesla batteries behave from what I read.

No offense, but we can’t draw any conclusions from one data point. This degradtion could be way above average, way below average, or right on the average.

While not charging habits that pertain to everyone, I love this kind of information and back and forth between EV users to actually compare vehicle types of battery types and also user
climates with the charging habits and also you know possible engineering changes that GM and other companies do to accommodate these battery life issues.

Are there any resources available like Voltstats for Bolts, LEAFs, Tesla’s and others to monitor battery capacity loss?

So many factors. Weather, amount and frequency of DC fast charges vs. Lvl 1 or Lvl 2. Even during style, battery load. I try to honor the buffer, and fast charge only once per week, but sometimes twice.

That is pretty darn good for a 70K miles car that goes thru so much deep cycling in just 2 years.

I am curious if the degradation curve is linear in the next 70K miles.

This was precisely why I justified using the federal tax credit and buying the largest pack available (Long range Model 3) stretching my budget. If I won the Lotto I’d buy a Model S 100D.

If I keep it ten years and drive it 200,000 miles, it still has life left in the tank. 200 miles max range and I’m trading it in.

At 238 miles range, looks like worse case scenario if you do not baby your pack you still should be good for eight or so years if you drive 20,000 miles per year. So not bad.

I don’t think this is unusual, I think the Teslas do something similar as well, they hit the sweet spot of 92-96 percent capacity range and then stay there for the next 250,000 miles or so, no?


Stay there? No data has shown that. The degradation doesn’t accelerate. But it still degrades slowly.

He speaks soo slowly…

So? Tesla have roughly the same degradation rate. This article makes it sound like this is a bad thing for the bolt

Stupid hat, silly attitude, a pack that got used about 2 to 3 times normal usage. And the pack only lost 8% in almost 2 years of hard use with frequent high discharge and then DC fast charging? Not bad.

I expected the comments on this article to be a garbage fire, but this is some of the most reasonable commentary I’ve seen on a potentially flamewar subject. Kudos to the InsideEVs commentariat!

I believe the degradation of his Bolt is closer to 6 percent not 8. 6% after 70k miles isn’t stellar but not horrible. Age of battery plays a role as well. I’d expect more degradation if the battery is 7 years old with 70k miles vs 3 years with 70k

That’s excellent news, about the same as other EVs. If they take care of their car it could last a long long long time.

My Bolt has lost 7.3% degradation at 17,000 miles.