The 40KWH Battery Topic

[HerdingElectrons]

So with the 40 kWh Leaf being out now for about a year, what are owners seeing in terms of battery degradation? Last I checked a few months ago:

-Dave in Olympia had (I think?) 2.75% degradation over 12,000 miles in Washington state

-Leftie Biker had 5.5% degradation over 6 months and only 1,000 miles in upstate New York (yikes, sorry)

But what are other Leaf owners/leasees witnessing on their 40 kWh Leafs?

I bought my '18 SL in Sept & have a bit over 6K miles on it. Zero QC's & 99% of charging is done at home L2 using the OEM EVSE. Anecdotally I typically charge in 2 hour blocks. From 8pm-10pm & or only from 3am-5am depending on SOC & what my rage needs are the next day. I charge the car daily except for rare low use cases.

I typically charge the car to 70-90% & 100% charge it every 1-2 weeks. I rarely get below 20% dash indicated but have been as low as 4% but have never seen any of the LBW or more dire warnings yet.

The car is garaged but is not climate controlled although the back of the fireplace is in the garage which does slightly passively heat the garage in the winter although the F/P insert keeps most of the heat in the home compared to a traditional F/P.

LS shows 96.66% SOH as of this morning compared to 99.2% a week into initial purchase so a 2.54% degradation so far over 4 months.

[sptleaf]

So after reading 16 pages of this topic, I'm a little disappointed to see the battery degradation happening to these newer 40 kWh batteries. I was hoping for some kind of improvement over the years. Having just got a 2019 Leaf S, I drove a 2016 e-Golf SE for 3 years. I charged it from 5% to 100% every day, and didn't think twice about it. when I turned it in after the 3 year lease, I didn't notice any range drop from when it was new.

Now that i purchased a Leaf instead of leasing, I have more incentive to research how to prolong the battery life. From what I've read about lithium ion batteries, it looks like the ideal long term storage state of the battery is 30% SOC.

http://www.electricvehiclewiki.com/wiki ... city-loss/

The 30% number is corroborated by the Nissan inventory storage document I received when I bought the car that also recommends the dealers store the battery at 30% if storing a new 2019 Leaf for longer than 90 days.

So now I have a choice to either baby the battery, and charge it from let's say 30% to 70%, or just drive the car and charge to 100% without thinking about it, and get a new battery under warranty if it drops to 8 bars within 8 years/100k miles. I mean, if I do see some significant degradation, there's almost an economic incentive to drive and recharge the battery aggressively just to get a new one within 8 years. Does anyone know the approximate range that would be left at 8 bars for the 40kWh battery? I'm guessing it's 66% or about 100 miles, but I've seen other posts where people have lots of bars, but not much range. I'm in the So Cal area and the car will be garaged at home and work. Besides this new battery concern, I really do like the car and am enjoying it thoroughly.

[LeftieBiker]

So now I have a choice to either baby the battery, and charge it from let's say 30% to 70%, or just drive the car and charge to 100% without thinking about it, and get a new battery under warranty if it drops to 8 bars within 8 years/100k miles.

That's what's called a "false dichotomy." The middle approach is what I'm taking: keep it charged between 50% and 80% unless you need 100%. Don't charge when the pack is hot, and especially don't QC when the pack is hot. Otherwise don't agonize over it. Or, if you are fine with reduced range, drive it like you stole it.

A safe range guess for a 40kwh pack just about to qualify for warranty replacement would be 80 miles with climate control use.

[WetEV]

So now I have a choice to either baby the battery, and charge it from let's say 30% to 70%, or just drive the car and charge to 100% without thinking about it, and get a new battery under warranty if it drops to 8 bars within 8 years/100k miles. I mean, if I do see some significant degradation, there's almost an economic incentive to drive and recharge the battery aggressively just to get a new one within 8 years. Does anyone know the approximate range that would be left at 8 bars for the 40kWh battery? I'm guessing it's 66% or about 100 miles, but I've seen other posts where people have lots of bars, but not much range. I'm in the So Cal area and the car will be garaged at home and work. Besides this new battery concern, I really do like the car and am enjoying it thoroughly.

How much do you drive per day?

Charge to 100% right before departure. Usually simple.

Slightly more complex would be to find out your average use, how long you need to charge to replace that use, and set up a timer to just replace average use. If you drive more, override the timer. If you drive less, skip plugging in.

My timer is set to charge for an hour, which replaces about 30% of the charge. I plug in when at or below 50%. So most of the time I'm between 40% and 80%. About every three days I plug in.

As for how long the battery will last, my guess is that the hottest places will see battery replacements, and the rest of the country will not. So use the scaling in the wiki and the closest climate to the climate where you live for an estimate. So Cal covers a lot of ground, from blazing hot to coastal cool.

"Phoenix, AZ " ,1.81

"Riverside, CA " ,1.09

If batteries just hit replacement at 8 years in Phoenix, then would hit replacement level in Riverside at 8* (1.81/1.09) or 13 years. If much worse, Nissan will bleed money on warranty replacements. So I doubt you have a chance of a battery replacement in 8 years. Unless So Cal means Palm Springs, CA.

[sptleaf]

Thanks for the replies. I'm in San Diego which is pretty moderate. I drive about 60 miles 3 days a week, and maybe 5-10 the other 4 days. So, I could easily set the timer to get back to a 70% charge and stay comfortably in the 30% -70% "ideal" range for 3 days a week. Then I could also leave the battery near the ideal 30% storage rate for 4 days a week, assuming I don't have any longer trips planned.

But, part of me is why bother, why should I need to manage this at all. Let's say I do all this and the battery lasts for 8.5 years then loses 4 bars. I could have just driven the car without a thought and charge to 100% nightly and maybe I get a new battery out of it after 6-7 years and come out ahead. I guess monitoring the rate of degradation would be the key to this bet, but from what I've seen from other people losing high percentage of SOC's after one year in hot areas, i'd say for them it makes more sense to just charge away and plan for the new battery within 8 years. In any case, the one redeeming grace is that even at 66% of my initial range, I could still get to work and back. Right now, I'm leaning towards "drive it like you stole it." Haha.

[WetEV]

Thanks for the replies. I'm in San Diego which is pretty moderate. I drive about 60 miles 3 days a week, and maybe 5-10 the other 4 days. So, I could easily set the timer to get back to a 70% charge and stay comfortably in the 30% -70% "ideal" range for 3 days a week. Then I could also leave the battery near the ideal 30% storage rate for 4 days a week, assuming I don't have any longer trips planned.

But, part of me is why bother, why should I need to manage this at all. Let's say I do all this and the battery lasts for 8.5 years then loses 4 bars. I could have just driven the car without a thought and charge to 100% nightly and maybe I get a new battery out of it after 6-7 years and come out ahead. I guess monitoring the rate of degradation would be the key to this bet, but from what I've seen from other people losing high percentage of SOC's after one year in hot areas, i'd say for them it makes more sense to just charge away and plan for the new battery within 8 years. In any case, the one redeeming grace is that even at 66% of my initial range, I could still get to work and back. Right now, I'm leaning towards "drive it like you stole it." Haha.

Choices are:

1) Take care of the battery.
Bad outcome would be the battery lasts for 8.5 years then loses 4 bars, unlikely unless you live in hot climate and you don't.
Good outcome would be to last far longer than the warranty.

2) "Drive it like you stole it".
Bad outcome would be the battery lasts for 8.5 years then loses 4 bars.
Good outcome would be warranty replacement at 7 years 11 months and 27 days, unlikely unless you live in hot climate and you don't.

Of course, you might enjoy option 2 more. Money and battery life isn't everything!

[DaveinOlyWA]

Figure out your needs (which seem modest) which has

distance you drive
considering weather, terrain
distance you "might" drive

then charge to the level that covers that.

As far as long term storage, I read "somewhere" that it should be 35% but that was years ago but I doubt much has changed.

I did a write up on my One year review and it delves into the battery situation (which I don't think is the main problem) including the BMS/LBC (which I DO think is the problem) and projected degradation.

https://daveinolywa.blogspot.com/2019/0 ... -leaf.html

[sptleaf]

Thanks for all the tips guys. Sounds like a good plan just charge what I need and stay within 30-75% SOC most of the time since it fits my drive profile. I take care of my stuff anyways so that’s what I’ll do. I was mainly playing devil's advocate in case someone saw a lot of degradation then it makes sense to try for the new battery.

Anyways here’s some data points from my new 2019 Leaf S purchase (no DC fast charger).

Attached are a battery inspection which has a nice full gauge and a reading of 552 CCA’s. I do not know that that is. The other is the storage document instructions for the dealers on how to store the Leaf at 30%.

[jmurtagh13]

Adding some data to this thread. I picked up my 2018 Leaf March 10th 2018 so it's 1 year old.

Mileage: 8,916
AHr 106.37
SOH 92.14%
Hx 112.23%

I live in Atlanta, No QCs, I charge early morning keeping the charge level between 30 - 75%. charge to 100% about once a month.
Max Battery temperature 97F, max temperature charging 85F. During the week the car is in a parking garage. I really try hard to baby this battery, yet I've lost almost 8% or at least that's what LeafSpy and or the BMS says.

What I'm seeing from reading these 16 pages, is it seems like battery degradation is tied more to time than anything else. Yes there is some variation due to the other factors. But it seems like no mater what, your're going to lose at least 6% in the first year. I have not seen a lot of data from 1 year old 40KWA leafs but the ones I have seen I believe have lost at least 6%.

The next year will be interesting to see if this trend continues, or if we determine that we're really not losing that much. As it's been said before the BMS may be the issue.

[LeftieBiker]

I had originally named the 30kwh pack the "Lettuce Pack" because it was apparently "wilting" so fast. Maybe the 40kwh pack should get that unfortunate moniker...if not, I shall dub it "Canary II."