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My understanding with other EVs, such as the Leaf, is that as the battery ages the reduced capacity is represented by not getting all of the bars once charging has completed. In fact the Leaf has distinct SOC bars and capacity bars making it quite clear. What will it look like for the Bolt?

My guess is the Bolt will get less than 20 bars (bars circled in red in the attachment) once charging has completed if the capacity is reduced, but will it? Another possibility is that each bar will be reduced so that they are less than 3 kWh each, but you still get 20 bars once charging has completed. Worst case scenario is there will be still be 20 bars worth 3 kWh each, but then the Bolt stops before running out of bars.

It's possible we don't know yet, which is good, but if someone happens to know either from first hand experience (exceptionally heavy footed driving or miles?) or just knows that'd be great.
 

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The Bolt engineers likely have designed the SOC bars to be the equivalent of a fuel gauge. When the car is fully charged (to whatever capacity the battery has), it will read 100%.

The LEAF is the only EV that comes to mind that ties the "fuel gauge" bars to the original battery capacity. But the bars do not show capacity as clearly as some assume. They values they represent are not linear and Nissan has in the past "adjusted" what each bar meant. It is also worth noting that their warranty is expressed in "bars" and not any actual battery capacity. If they do a software update, 9 bars may go from representing 70% (I think that is the current assumption from LEAFspy users) to a lower value such as 65%. Presto-changeo. Your battery showing 8 bars now shows 9!
 

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on Tesla's the only way to tell is that the rated range (ideal miles you can drive) becomes less than it used to be when he car was new - virtually no one on the forums has reported > 5% loss after 3-4 years…most people are seeing far less...a couple of people had more than 10% loss after a 3 years, but Tesla replaced their batteries.

the only real way to know is the see the raw SOC % numbers - and I'm not sure if those numbers are visible with the normal consumer software.
 

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I've read elsewhere on the forum (I can't find it again) that some are using the "Hilltop" setting, which charges to 80% capacity, to help prolong battery life. The implication is that we who charge to 100% are actually inducing battery degradation. Is there anything to this? I can't find anything in the manual that warns against charging to 100%. How do we know using Hilltop prolongs battery life?
 

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charging over and over to 100% damages LiON batteries - if you don't need the extra range I recommend only charging to hill-top reserve - all EV's to date come with default charge settings to not charge to 100% - and it's generally accepted/supported doing that over and over decreases battery life.
 

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I've read elsewhere on the forum (I can't find it again) that some are using the "Hilltop" setting, which charges to 80% capacity, to help prolong battery life. The implication is that we who charge to 100% are actually inducing battery degradation. Is there anything to this? I can't find anything in the manual that warns against charging to 100%. How do we know using Hilltop prolongs battery life?
It's broadly accepted that it's better to avoid fully charging the battery except in circumstances where you know you're going to need the full range. What isn't known is exactly how much a full charge affects battery life compared to "Hilltop". If it's something like a 20% difference in capacity after 5 years it would argue much more strongly for following the advice than if it was only a 5% capacity difference.

Still, it just seems sensible to me to play it safe and avoid the full charge unless you expect to need it.
 

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http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries

Thanks David for this very useful link and for all your extremely thoughtful and educational posts on this site. I will begin using the Hilltop setting unless I'm heading out on a long trip.

Another quote from you David: ...all EV's to date come with default charge settings to not charge to 100% -

Does this mean that Chevy has built in a safety margin for charging their batteries so that when we see an indication that our cars are "fully charged" it may not actually be 100%? I think Tesla does this.
 

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charging over and over to 100% damages LiON batteries - if you don't need the extra range I recommend only charging to hill-top reserve - all EV's to date come with default charge settings to not charge to 100% - and it's generally accepted/supported doing that over and over decreases battery life.
But most all this research has been on cell phone (non-cooled) LiON batteries. What is your learned opinion on the Bolt's temperature-managed battery pack? Not in actual numbers or percentages, just do you think they will follow the same curves, or maintain performance longer? (I know we all hope so... e.g. the "Hilltop Reserve" practice.)
 

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I'm going against the grain, but commonly accepted and true are not always equal.

That oft cited research is indeed mostly on cell phone batteries with charge/discharge cycles very different than what occurs in an EV.

As to "most" EV's having the ability to charge to a lower that 100% (indicated - not an actual 100%), that list is limited to:
Tesla S/X
Bolt EV
Mercedes B250e

My personal experience has been charging to 100% almost every evening for almost 4 years and 40K miles. No noticeable loss of range.

The only EV with significant battery degradation issues has been the LEAF. I don't believe it to be a coincidence that it is a passively cooled battery.

Will using hilltop reserve harm the battery? Very unlikely. But I would charge to 100% occasionally for cell balancing.

Will it prolong battery life on the Bolt - maybe. It may be that other environmental factors and usage patterns impact the battery more than charging to whatever percentage the indicated 100% really is.

If you read the LEAF forums, some people go to crazy lengths to baby their batteries (timing charging to get to 80% just before they leave for work, never charging above that amount, parking only in the shade, etc). Some still report degradation issues.
 

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the 100% issue from what I've been told has nothing to do with the thermal issues - they are independent of one another - charging a temperature regulated LiON battery to 100% (and letting it sit at 100%) is what does the damage, doing the same thing with the battery outside of optimal temp ranges does more damage than the 100% issue alone - never charging a LiON battery to 100% but mismanaging the temperature also damages it.

basically LiON batteries are fragile...LOL

Tesla's charing control software will warn you once you have charged 5 times in a row to 100% and ask you nicely if you forgot to lowering your charging %'age to the "daily" setting - 90%

My Chevy Bolt came with hilltop reserve enabled so I guessing that's for two reasons
1. it's bad to charge LiON batteries to 100% over and over
2. charging to 100% limits regen braking and can be disconcerting if you're not expecting it

I know for a fact the following EV's default charging setting is less than 100%

Ford Focus EV
Tesla
VW Golf EV
Toyota RAV4 EV (battery/drive train by Tesla)

I'm guessing it's true on other EV's - so my bad if that's not true.
 

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The Leaf has a setting similar to Hilltop Reserve that limits charging to 80%. It's not on by default but it is there.
 

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I know for a fact the following EV's default charging setting is less than 100%

Ford Focus EV
Tesla
VW Golf EV
Toyota RAV4 EV (battery/drive train by Tesla)

I'm guessing it's true on other EV's - so my bad if that's not true.
The FFE and the eGolf do not have a setting less for than 100% (by default or not). Just looked at the manuals to confirm. And if you know how to set it there are lots of owners on the respective forums that would like to know how.

No menu option for a reduced SOC:
Ford Focus Electric
VW eGolf
BMW i3
Kia Soul EV
Honda Clarity Electric
Honda Fit EV
Fiat 500e
Mitsubishi iMiEV
smart fortwo ED
Nissan LEAF (2014+)
Hyundai Ioniq Electric

So the list with the option is as follows:
Tesla
Mercedes 250e (Tesla drivetrain)
RAV4 EV (Gen2 with Tesla drivetrain)
Bolt EV
Pre 2014 Nissan LEAF
 

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I think this discussion goes hand in hand with the posts about the true size of the battery. ( most seem to think the bolt is 66kwh battery)which means a 100% charge is actually 90% charge. Please be careful when you use ?100% charge?, verbiage. Which I think most are assuming but the average person may not know reading these posts.
Also the SOC (state of charge) data is fairly accurate for some reasearch. ( non cell phone batteries) which is 55% or less to store for bestlong term battery health.
However some of the problems is the reasearch hasn?t been with these new batteries. But Chevy has there ads about the ?new? bolt battery and they tested it but haven?t released any data hay I know of. Whould be very interested it that data.
I will be a test subject I believe. I drive 130-150 miles everyday 7 days a week. I charge everyday. I plug in so it completes charging between 4-6 am every morning. So SOC at full is a shorty period of time and in use a lot. When I won?t use the car on a weekend I don?t charge it till I know I need it.
I too am very interested to see if their is any way to ?see? the battery degradation over time, like the leaf.
Only time will tell.
 
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