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Hi all, I think this is the right location for this post, but if it's not, feel free to move it. :)

I was wondering what the lifetime of the batteries would be on the Chevy Bolt. I know this is a bit premature since they haven't sold any yet and aren't available, so we don't have any real life data on it, but I thought we would at least start the conversation with known EVs and the battery type being used in the Bolt.

Thanks!
 

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In the US, it carries an 8 year 100,000 mile warranty (except California is 10 yrs 150K).

Virtually every EV sold currently uses Lithium ion batteries (with varying chemistry).

How fast a battery degrades depends on so many factors there is no easy answer (i.e in 50 months you'll have 94.5% capacity left), and how you treat your battery, the climate you live in, where you park, how and when you charge, etc will all influence battery life.

Larger pack size and active thermal management both seem to be conducive to battery health, and the Bolt checks both those boxes.

BTW:
The charging practices threads on EV forums are equivalent to the "what's the best oil" threads on ICE forums - there is no definitive answer and scientific studies with a narrow scope and/or anecdotal stories are extrapolated by both sides to include all batteries in all EV's by all drivers. I tend to go with the car manufacturers recommendations, others swear that is the worst thing you can do for your battery. YMMV.
 

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In the US, it carries an 8 year 100,000 mile warranty (except California is 10 yrs 150K).

Virtually every EV sold currently uses Lithium ion batteries (with varying chemistry).

How fast a battery degrades depends on so many factors there is no easy answer (i.e in 50 months you'll have 94.5% capacity left), and how you treat your battery, the climate you live in, where you park, how and when you charge, etc will all influence battery life.

Larger pack size and active thermal management both seem to be conducive to battery health, and the Bolt checks both those boxes.

BTW:
The charging practices threads on EV forums are equivalent to the "what's the best oil" threads on ICE forums - there is no definitive answer and scientific studies with a narrow scope and/or anecdotal stories are extrapolated by both sides to include all batteries in all EV's by all drivers. I tend to go with the car manufacturers recommendations, others swear that is the worst thing you can do for your battery. YMMV.
What would warrant a battery replacement ? Like.. if the batteries capacity was significantly lower than it should be or does it have to be non-functioning ?
 

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What would warrant a battery replacement ? Like.. if the batteries capacity was significantly lower than it should be or does it have to be non-functioning ?
That is the million dollar question.
The Federal and California requirements do not define any criteria.

After a Class action lawsuit, Nissan put out hard numbers of 70% after 5 years or 60K miles.
The i3 is 70% during the entire 8yr/100K warranty.

So 70% seems to be emerging as a standard, but nothing is binding at this point. I don't think the Spark (or Volt?) list any specific numbers. When I was first looking at EV's, it was the LEAF or iMiev. When pushed, Mitsubishi said 10% degradation a year would be considered "normal" and not excessive. The Fit EV has been exceptional - when I asked on the forums, only one person said "I think I lost a couple of miles range, but they added workplace charging so I drive it a bit harder as well". There are a handful with over 50K miles in <3 yrs with the highest reported being 64K.

It's also possible for a manufacturer to maintain capacity by making more of the "buffer zones" of the battery available as it ages. Say, for example, the Bolt has 60 kWh available out of a pack size of 66 kWh. If, as the battery ages, its capacity dropped they could still make 60 kWh available (out of the now reduced 64 kWh pack capacity, ie).
 

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Are you saying that it's been put out by GM that the actual battery pack size is 66kwh?
No, I'm not saying that is the exact spec, but we do know the usable portin will be pretty darn close to 60 kWh and there is always some buffer (the test drives from Monterey to Santa Barbara by journalists reported using 58-59 kWh with up to 50 miles range remaining).

We do know:
288 LG cells
3p96s configuration (groups of 3 in parallel)
The best information has LG with 3 possible cell specs (all 3.75 V)
55 Ah
63.35 Ah
65 Ah (used in the new 40 kWh Renault Zoe)

The 55 Ah version would yield a 59.4 kWh pack (288 x 3.75 x 55). We know that the usable amount is greater than this, so cross this one off.
63.35 would yield 68.4 kWh
65 would be 70.2 kWh

The 65 Ah version is the latest from LG and is what I believe most likely to be used in the Bolt. The 70.2 with 60 usable would fit with the conservative tack GM has taken with the Volt, and the upgrade from 63.35 to 65 could account for the "more than 200" mile range becoming 238.

Nothing official from GM, but that's my guess
 

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On the Chevy Warranty Website, under the Electric Hybrid Warranty section, it outlines the warranty terms. It does not mention a specific capacity warranty.

http://www.chevrolet.com/owners/warranty.html#

However, I did find this video posted that has a test drive with GM Project Manager Darin Gesse (manger over the Volt and Bolt projects) and at 16 minutes in he mentions the warranty.
 

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However, I did find this video posted that has a test drive with GM Project Manager Darin Gesse (manger over the Volt and Bolt projects) and at 16 minutes in he mentions the warranty.
And it contains the CYA phrase "up to".

If you took his words literally, it would mean that it will have no more than 65% capacity in 5 years.....
 

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Here's what I found on Tesla batteries

This applied across the board, whether it was a 60kWh pack or an 85kWh pack — it was an across-the-board drop in numerical range, not a percentage from the battery's original capacity. There was some variance in the numbers, as one would expect from results reported by real-life drivers in a wide range of environmental and driving situations — some saw as little as 0.16 miles loss per 10,000, while others saw as high as 5.1 miles per 10,000 driven.
According to the U.S. Department of Transportation, the average driver in the United States puts 13,476 on their personal vehicle, which works out to about 3 miles per year in decreased range — it would take the average owner of a 215-mile-range Tesla model 3 with re than five years to dip that range under the 200-mile mark.


I can't post the link because of my low post count here but just google the above text and you'll find it.


Tim
 

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This is a vast amount of knowledge being thrown around here. But I'm definitely learning quite a bit, so thank you guys very much in advanced.

Being able to stay on top of 200 miles after 8 years would be remarkable, but dipping under in a bit over 5 years is quite the difference no ? Understandably that's comparing a 238 mile range to a 215 mile range but were talking a difference of 23 miles ?
 

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Sorry to bring this back up again but I read something on AutoEvolution and thought I would share it. They took this snippet from the owners manual and it says the the battery may degrad 10% to as much as 40% capacity over the warranty period. From their stand point, their okay with 10% or less after the 8 year period but think 40% is not cool at all because in theory it would bring the bolt to 143 miles of range after 8 years.
It’s worth remembering that Nissan settled a class action lawsuit over a similar problem with the 2011 and 2012 Leaf. 18,588 owners were covered by the settlement. Some brought their Leaf vehicles to Nissan to repair the battery to at least 70% capacity or, if not possible, get the battery replaced.
Link: http://www.autoevolution.com/news/2017-chevrolet-bolt-battery-may-degrade-as-much-as-40-over-the-warranty-period-113534.html#
 

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GM is legally covering up their butts in case someone does manage to degrade their batteries that much. I'm not sure if that's what the engineers predicted.
 

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Sorry to bring this back up again but I read something on AutoEvolution and thought I would share it. They took this snippet from the owners manual and it says the the battery may degrad 10% to as much as 40% capacity over the warranty period. From their stand point, their okay with 10% or less after the 8 year period but think 40% is not cool at all because in theory it would bring the bolt to 143 miles of range after 8 years.


Link: http://www.autoevolution.com/news/2017-chevrolet-bolt-battery-may-degrade-as-much-as-40-over-the-warranty-period-113534.html#
I don't think we have anything to worry about that "10-40%" degradation warning. The VOLT has a 30% degradation warning, yet not a single Volt owner has reported having their batteries replaced under warranty for degradation reasons (oldest Volts are almost 6 years old now). Volt batteries HAVE been replaced for other reasons, but NOT for degradation. I have a 2012 Volt with nearly 50k miles (and over 40k on battery). I still get 10.5 kWh out of it on a full charge. Now that I think about it, I usually got 10.2-10.4 kWh out of the battery when it was brand new, so if anything, I have a reverse degradation issue. Lol

Look at it this way: the almighty Tesla does not warrant against capacity loss (and sure as heck doesn't put a specific figure out there). Any claims for unusual degradation are taken on a case by case basis at Tesla. So in that sense, we're actually fortunate GM has put out a specific number, even though it is 40%.

I used to have a Ford C-Max Energi, and while I never experienced it, many owners are now reporting their HV batteries have degraded 30-40%....in less than 4 years/40k miles! And the real kick in the nuts? FORD admits there is a specific set of conditions they will replace a HV battery for capacity loss, but they say that information is proprietary and can't be divulged! WHAT?! So basically, they can deny battery degradation claims all day long and hide behind their proprietary info wall.

Back to the Bolt's battery, I'm sure there will be SOME kind of degradation experienced over time, but nothing like 40%. I'd look to the Spark EV owners and see how their batteries have held out, as the usable capacity % on a Spark EV approaches 95%.
 

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Thank you very much ! That definitely puts me at ease but I'll be sure to check out the Spark boards to see how those guys are playing out. I've never been a Ford person to be honest but hearing that makes me want to shy away from them even more lol.
 

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So what should we do as soon to be Bolt owners to extend the life of our batteries? What are proper practices to minimize battery degradation?
 

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So what should we do as soon to be Bolt owners to extend the life of our batteries? What are proper practices to minimize battery degradation?
Hopefully they learned a thing or two about what Nissan had going on in regards to battery life and other things impacted by including/excluding certain things:
I was also critical of their decision to exclude a sophisticated thermal battery management system which would help maintain a consistent range throughout varying ambient temperatures as well as help extend the battery’s life. This omission has proven costly to them as some LEAF customers that live in hot weather climates like Arizona have experienced unacceptable battery capacity loss; prompting buybacks, battery replacements and has even forced Nissan to change their battery warranty to now include capacity loss.
http://insideevs.com/understanding-battery-capacity-loss-from-a-four-year-bmw-electric-trial-veteran/
 

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So what should we do as soon to be Bolt owners to extend the life of our batteries? What are proper practices to minimize battery degradation?
Engage Hilltop Reserve mode (no, you don't need to live on top of a hill to use it). You can set your home (as well as any other place) as a location where HTR is activated, and it limit charging to 90% of SoC.

There is also a 40% "priority charging" feature (charges to 40%, then stops). That could be used when you are going to be gone for an extended period of time, and don't want to keep the Bolt at a high SoC.
 
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