The 62kWh Battery Topic

[DaveinOlyWA]

When I first got my Leaf I took some trouble to mange the SOC, trying to stay in the 30-80% range. But for the past year or more I've just been waiting until the SOC drops below 40% and then charging to 100% - usually about twice a week. The car never stays at 100% for very long, and our garage moderates temperature extremes.

With frequent charges to 100% I've been able to watch for any degradation trend, as shown by a drop in the number of GIDs at full charge. Over the past 18 months there has not been any noticeable loss of capacity; full charge consistently range from 695-710 GIDs. So I don't think the BMS is just lying to us to save warranty costs.

You realize your very small POV conclusions violate PROVEN science, right?

I also hope you realize that your evaluation of "my battery is ok" is provided by the entity that "needs" you to be happy until the warranty runs out?

But what I would really like more information on is the "trouble" you had maintaining a targeted SOC?

 

[oxothuk]

When I first got my Leaf I took some trouble to mange the SOC, trying to stay in the 30-80% range. But for the past year or more I've just been waiting until the SOC drops below 40% and then charging to 100% - usually about twice a week. The car never stays at 100% for very long, and our garage moderates temperature extremes.

With frequent charges to 100% I've been able to watch for any degradation trend, as shown by a drop in the number of GIDs at full charge. Over the past 18 months there has not been any noticeable loss of capacity; full charge consistently range from 695-710 GIDs. So I don't think the BMS is just lying to us to save warranty costs.

You realize your very small POV conclusions violate PROVEN science, right?

I also hope you realize that your evaluation of "my battery is ok" is provided by the entity that "needs" you to be happy until the warranty runs out?

But what I would really like more information on is the "trouble" you had maintaining a targeted SOC?

The "trouble" is keeping my wife happy - someone who is totally uninterested in the the technical aspects of cars be they EV or ICE. It's my job to make sure she doesn't have to worry about range for her daily driving, just as I was responsible for filling the gas in her previous car.

I don't doubt that a closely managed SOC is better for battery longevity, but the question is "how much better" and "is it worth the effort". I just try to avoid the extremes which are most damaging (running down to empty, staying at 100% SOC in hot weather).

As for the trustworthiness of the LeafSpy data, I can only say that the trend in SOH mirrors what I see in the trend of GIDS after a full charge. And I don't think the GIDS are being devalued, since I would then notice a difference in miles/kWh.

 

[DougWantsALeaf]

I do believe the BMS is both doing and educated guess about capacity as well as managing a buffer to keep the pack within warranty specs. It does seem to work, and also give you that magical artificial feeling of a pack that doesn't degrade for a couple years (or even go up modestly). My 2019 S+ has been sitting at/around 93% SoH for 2 years. My 2019 SV+ around 90% SoH for a similar window.

 

[DaveinOlyWA]

When I first got my Leaf I took some trouble to mange the SOC, trying to stay in the 30-80% range. But for the past year or more I've just been waiting until the SOC drops below 40% and then charging to 100% - usually about twice a week. The car never stays at 100% for very long, and our garage moderates temperature extremes.

With frequent charges to 100% I've been able to watch for any degradation trend, as shown by a drop in the number of GIDs at full charge. Over the past 18 months there has not been any noticeable loss of capacity; full charge consistently range from 695-710 GIDs. So I don't think the BMS is just lying to us to save warranty costs.

You realize your very small POV conclusions violate PROVEN science, right?

I also hope you realize that your evaluation of "my battery is ok" is provided by the entity that "needs" you to be happy until the warranty runs out?

But what I would really like more information on is the "trouble" you had maintaining a targeted SOC?

The "trouble" is keeping my wife happy - someone who is totally uninterested in the the technical aspects of cars be they EV or ICE. It's my job to make sure she doesn't have to worry about range for her daily driving, just as I was responsible for filling the gas in her previous car.

I don't doubt that a closely managed SOC is better for battery longevity, but the question is "how much better" and "is it worth the effort". I just try to avoid the extremes which are most damaging (running down to empty, staying at 100% SOC in hot weather).

As for the trustworthiness of the LeafSpy data, I can only say that the trend in SOH mirrors what I see in the trend of GIDS after a full charge. And I don't think the GIDS are being devalued, since I would then notice a difference in miles/kWh.

We all have challenges to juggle and you can rest in the fact that the large capacity is sufficient enough that when noticeable changes do happen, you may be able to review this conversation in a different light before its too late.

 

[GerryAZ]

If you look through this thread, you can see my quarterly full discharge/recharge tests. The car is now over 4 years old with over 71,000 miles and still has all 12 capacity bars. The energy storage capacity of the battery (as measured by a revenue accuracy meter on the 240-volt circuit feeding my EVSE) has dropped commensurate with GID readings at full charge, AHr readings, and SOH readings from LEAF Spy. My 2015 was down to 8 capacity bars in less time and distance. The original battery in the 2011 was down to 8 capacity bars at half the mileage with a little over 2 years of use.

I almost always charge to 100% and discharge deeply before recharging. The only thing I do to help reduce battery deterioration is that I make sure not to leave the car parked at 100% SOC for extended time. I did the same with my 2015 and with the 2011 before that. The difference is that I charged the 2011 and 2015 every night while I charge the 2019 every 2 to 4 days, depending upon daily miles driven and range needed the next day.

 

[Marktm]

If you look through this thread, you can see my quarterly full discharge/recharge tests. The car is now over 4 years old with over 71,000 miles and still has all 12 capacity bars.

Attached is a similar log of my 2021 SV Plus. I'm in a rather hot Houston, TX environment, have only ~18,000 miles, have used only level II charging, and have done my best to keep battery temps down (shaded parking, garage kept, etc). So at 2 1/2 years, I'm down to about 93% SOH. Not sure how all this compares to your 2019 battery performance as the mileages are so different, charging style quite different, and likely other "ambient condition" differences - so it all becomes someone anecdotal :mrgreen: , but IMO, good information.

 

[GerryAZ]

For ease of comparison to Marktm's data, here is my latest data:

Phoenix temperatures are higher than Houston's and I drive more miles per month so the capacity loss of my car is slightly higher than Marktm's. My car was down to 92% at 24 months and 35,000 miles vs. 28 months and 17,300 miles for Marktm's car.

 

[DaveinOlyWA]

For ease of comparison to Marktm's data, here is my latest data:
LEAF 2019 Battery Information 11B.png
Phoenix temperatures are higher than Houston's and I drive more miles per month so the capacity loss of my car is slightly higher than Marktm's. My car was down to 92% at 24 months and 35,000 miles vs. 28 months and 17,300 miles for Marktm's car.

Your pack has never had an up adjustment? Interesting. Have to wonder why you chose to charge a few times a week when it appears your range is more than sufficient to user a lower SOC range on a daily basis?

 

[GerryAZ]

My 2019 pack has had a few "up adjustments" but these quarterly full discharge/charge tests happen about a month after the adjustments so the fluctuation is not noticeable unless I look at the daily data. I decided early on that I would just charge and drive normally. The 2011 could be set to stop charging at 80 percent, but that would not allow for much extra driving on a given day so it was almost always charged to 100 percent overnight. The 2015 did not offer the option for 80 percent charge and had the same battery capacity (but a lot better chemistry) so it was typically charged fully overnight. The 2019 does not offer an option to limit charging automatically so I choose to charge fully and then discharge deeply before charging to reduce the time spent at high SOC. I also believe that charging fully and discharging deeply on a routine basis helps to keep the cells balanced.

Statistics after 72,051 miles as of today:
AHr=146.89
SOH=83.27%
Hx=57.19%
QC=26
L1/L2=510
GIDS prior to charging=277
GIDS after full charge=624
Average miles/charge=134.42 (without odometer error correction)
Miles driven (dash display)=88.1
Miles driven (actual)=91.9
Remaining miles (dash display)=67
SOC (dash display)=35%
Miles/kWh (dash display)=3.2
Charging energy (meter)=33.69 kWh
Miles/kWh (actual includes odometer error using energy measured from meter)=2.73
Capacity (dash display)=12 bars
Temperature (dash display)=6 bars (center of bar graph)
Estimated charge time (L2 dash display)=6.5 hours
Actual charge time=6:36
Highest battery temperature before charging=91.2 F
Highest battery temperature after charging=92.0 F
Cell voltages after charging:
minimum=4.192
average=4.196
maximum=4.203
delta=11 mV
SOC at full charge=96.1% (LEAF Spy); 100% (dash display)

The internal resistance of the battery seems to be increasing over time because I notice more heating during quick charging and highway driving. GIDS at full charge is now slightly higher if the battery is charged from higher SOC than when it is deeply discharged before charging (this was not noticeable when the car was newer). I needed full range today so the car was charged last night even though it still had 35% SOC when parked.

 

[DougWantsALeaf]

We recently visited our daughter who is driving our S+. The last adjustment was modestly up again!

93.1% SoH 106.65Hx 26K miles

Built September 2019

My LS no longer works due some socket issue with how the dongle works with the OS and Bluetooth. Maybe time for a new phone.

 

[xafalcon]

Does anyone have the specifications on the HV battery fuse in the 62kWh battery pack?

I'm transplanting the pack into a 30kW 2016, and keeping the 160kW inverter for another project. I'd rather not open the battery pack just to harvest the fuse (to keep with the inverter)

TIA

 

[watchdoc]

2022 SV+ with 27k miles and just had my first positive adjustment in two years. 91.93% to 92.80% HX 111.28 an 163.7AH

 

[knightmb]

Because I like to post LeafSpy screenshots with superstitious mileage.

 

[knightmb]

Another more Recent One from LeafSpy.

 

[Mcflocki]

I recently purchased a used 2020 SL Plus. I have read all 69 pages of “The 62kWh Battery Topic” I appreciate all the information that this forum provides. I also read a number of different articles and battery studies. I decided to add my 2 cents to the discussion. I’m a journeyman Electrician but I’m not a battery expert. I installed my own solar with battery backup system at my home and I monitor and maintain that system. My backup battery system does not have as good a BMS as these cars do, it protects the cells and balances well but it gets lost on SOC over time and needs adjustment. Top balance or bottom balance depending on the time of year. My system can run off the SOC, the voltage or a hybrid method. The best is a hybrid method with some monitoring and a top or bottom balance to reset the SOC. These cars are much more accurate and reliable on all these measurements, thankfully. I don’t believe it’s necessary or very helpful for the average user to discharge to 0% and charge to 100 % just for the extra accuracy that might give your BMS for a timeframe.

I want my car to be convenient and reliable and I plan on keeping it for a long time. I like the term GOM for the range and I think it should also apply to the SOH. The only way to tell the true state of health would be destructive testing, there are multiple physical changes that decrease the battery health and can lead to failure that are hard to measure short of opening it up. Thanks to many of you that have kept very good records and shared that information with us we can make some very good generalized statements about the battery and the LeafSpy information. I believe that the SOH is mainly tied to the total Ahr/GID. I don’t believe that abuse helps the battery, I’m sure most of you don’t. It can be frustrating when you baby your car and someone else brakes all your rules and seems to have better SOH than you. I don’t believe that the true SOH actually improves but the SOH guess goes up or down with time with the many factors that affect the BMS and its guess of what full capacity is. Based on these beliefs I think you should take the SOH with a grain of salt especially if you keep your car in a small range of SOC. When someone does a long drive that uses most or all of the battery capacity/completes a full discharge and top up capacity test the BMS gets a better reading of full capacity and the SOH is often adjusted up to reflect that. This doesn’t mean that the battery health improves from fast charging or fully discharging and charging the battery to 100%, it just changes the SOH to better reflect the available capacity.

I don’t believe there is any hidden capacity, the system seems to determine the top and bottom charge by voltage. The studies and the standard for NMC batteries is 4.35 volts = 100% SOC. The car companies want to say the highest number to make the car sound better but what really counts is usable power and 59-60ish usable is taking 62 KWH batteries when charged to 4.35 volts and limiting them to 4.2 volts because that improves the longevity of the battery. 4.2 is about 96.5% of the battery usable but most people don’t drain it all the way to the cut off so what’s actually used varies. They don’t even promise that the brand new batteries come with any specific amount of capacity. What they are really doing is making batteries to a standard and batteries of this size, weight, configuration and chemistry should be able at 4.35 volts to the cut off provide nominally 62 KWH of power. All batteries are different and each car will be a little different when new and through their usable life. Where then would this hidden capacity come from? The car would have to have unused cells that could be accessed or start letting you access higher voltage that would negatively affect the life of the battery. The only alternative would be manipulating the numbers in the system but GerryAZ has done some very thorough testing and it doesn’t seem to show any kind of number manipulation shenanigans going on.

I want to try and encourage and help anyone I can on this forum to enjoy their car and put aside their fears and superstitions as much as possible. These cars are rated just below Tesla in reliability and they cost a lot less. That’s the reason I bought it over the other options I could afford. There is a wonderful community of people that love these cars and want to share and learn. There are also some ideas that hurt and those are the ones I want to address. There was a post that mentioned having range anxiety when they had the older Leaf and contrasted that with the new Leaf plus and they said they had charge anxiety. No one should have anxiety about their car. I wouldn’t say that I had charge anxiety but I’m a perfectionist and I always want to do things the “right way”. The thing is, there is no “right way” only a right way for you. If charging 40-60 makes you happy and it works for you then that’s great. If charging to 100% helps you not have range anxiety and you need the range, I’d recommend setting the timer to finish charge close to leaving time and enjoy your car. If you try to follow all the rules about best practices for NMC batteries and your frustrated that your SOH isn’t as good as the person that breaks all your rules, remember that SOH is not as important as it seems. Following the rules give you the best chance of making the battery last longer than average. I believe it’s a game of odds and chance mixed with a bit of consequence. You’ll improve the odds if you baby the car but it’s no guarantee that you’ll be trouble free. You’ll eventually have consequences if you abuse the car but you can be lucky for awhile. The SOH doesn’t take everything into account, and the fact that Learjet had a bad cell that was able to throw codes and get the module replaced but still had relatively high SOH shows that the BMS still assumes full voltage capacity in its AHR and full SOH of that capacity even though the cars true capacity was definitely reduced by the bad cell. The true SOH can’t be measured by the BMS only destructive testing or dissecting the battery and studying it in a lab. That’s why the labs recommend certain types of use cases. Remind yourself that these batteries have done well even when abused and when you try to take care of it your odds are great. I bet that the people that keep a small window of SOC and show a lower SOH would see their next SOH adjustment go up significantly if they started doing some deep cycling of their batteries. This doesn’t mean the deep cycling improves actual battery health, it just changes the calculation made by a BMS.

Personally I’ll try to keep my car between 40-80 SOC especially in the winter when I don’t feel comfortable on the lower SOC. I plug it in everyday with lv1 at work but I drive more than that can restore so it slowly gets to the lower end of my SOC goal then I use level 2 charging also at work and bring it up to the top of my goal. When I plan on driving more a certain day I charge it up to 90-100% but have it finish charging as I’m about to leave. I only have to use the timer when I lv 2 charge so it’s very convenient and easy to keep the car charged in the range I like. As long as you don’t get some bad cells and you don’t drive a lot every day then these cars should be daily commute ready for a long time and even worst case scenario bad cells can be replaced. All cars have maintenance and eventually failures that can be fixed. Figure out a method that works best for you and enjoy the ride.

 

[Mcflocki]

LeafSpy readings from today

 

[leafnissancyp]

Here is the values for March 2020 Leaf e+ 62KW.. I also check the values using LeafHacker android app which shows 94.43 Battery SOH and SOH 90.83% (same with LeafSpy app). But I do not know what the Battery SOH is. Owner of the app said me that this value coming directly from VCM.

 

[DougWantsALeaf]

Our 2019 S+ has finally dropped below 93% SoH. It held 93% for a couple years which was nice to have no degradation for a chunk of time. This Leaf is primarily DC charged for the past 15 months.

 

[Learjet]

Pretty impressive!

Last check my 2019 was at 88.36% at 36,000 miles. Only about 15 miles less on the GOM when fully charged compared to new. Still shows about 205-208 miles fully charged. What hurt me is the year it sat on the dealers lot fully charged

 

[Leaf4al]

My 2023 SV plus is now 92.9 SOH at 12160 miles. I’ve only done 6 QCs. The rest were all level 2s. It is garaged all of the time. Is my leaf degrading too fast?