The 40KWH Battery Topic

Here are my (late) July stats. I'd like to note that part of the reason I'm cooling my garage is to provide a "control" - a car that isn't getting hot regularly, if at all. So far it doesn't seem to matter much.

SOH: 97.96

AH: 113.08

Hx: 102.91

SOC: 72.7

GIDs: 373

Temp sensors: 74.3, 74.7, 75.4 (These readings are about 4-8F hotter than the may & June readings, and 30F warmer than the April readings.)

June's readings:

SOH = 99.25

AH = 114.57

Hx = 100.77

LeftieBiker said:

Here are my (late) July stats. I'd like to note that part of the reason I'm cooling my garage is to provide a "control" - a car that isn't getting hot regularly, if at all. So far it doesn't seem to matter much.

SOH: 97.96

AH: 113.08

Hx: 102.91

SOC: 72.7

GIDs: 373

Temp sensors: 74.3, 74.7, 75.4 (These readings are about 4-8F hotter than the may & June readings, and 30F warmer than the April readings.)

June's readings:

SOH = 99.25

AH = 114.57

Hx = 100.77

Click to expand...

Seems like you are losing capacity faster than me. SOH 1½ in a month? Sounds like you had at least one big drop in there somewhere.

I have now had 2 and there seems to be no reason for them. One happened randomly during a short 3 day period of light usage while the other happened when parked in the Sun for 12½ days.

But I have done a half dozen road trips consisting of 5+ QCs, temps in near or over 120º without any major damage.

So wondering if BMS does a recalibration randomly that accounts for these big drops?

I see two reasons for the big drop. First, the interval is more like 6 weeks - I was late with this measurement. Second, the battery temp as measured by the sensors, while not high at all, was much higher than it was in the Spring. The "Lettuce Pack" may be just like the Canary pack, in that anything above actual cold temps accelerates degradation.

Just for comparison there's probably a pole somewhere where this is all charted but I'm at 3200 miles 1.5% loss if this rate stays the same I should be at 66% at 72533 miles I am sure the degradation will increase as the battery gets older.
https://youtu.be/5vaaM7MBj74
I also changed out the headlights and reverse lights to LED the headlights look way better

There are two or three topics on this already. Mods, please merge.

How many threads are there for this?

I’ve been trying to figure out my degradation with charge/drain percentages. According to my calculations (40-something data points), I’ve lost about .6kWh. I just rolled over to 10,000mi the other day. Even if it accelerates, that puts me on pace for 80% to 85% capacity at 100,000mi (assuming a starting pack size of 37.5kWh).

Here is one I started. http://www.mynissanleaf.com/viewtopic.php?f=9&t=25773

Locked- see link in post above.

I finally did my August LeafSpy read, and I finally charged to 100% before doing it. The cell voltages leveled out nicely after EQ, with only a 9MV spread. SOH only dropped a little! Maybe the garage cooling is actually helping. Stats:

SOH: 97.76

AH: 112.85 (but only 109 on summary screen!)

Hx: 103.87

SOC: 97.2

GIDs: 485


Temp sensors: 73.8,75.9, 74.1

LeftieBiker said:

I finally did my August LeafSpy read, and I finally charged to 100% before doing it. The cell voltages leveled out nicely after EQ, with only a 9MV spread. SOH only dropped a little! Maybe the garage cooling is actually helping. Stats:

SOH: 97.76

AH: 112.85 (but only 109 on summary screen!)

Hx: 103.87

SOC: 97.2

GIDs: 485


Temp sensors: 73.8,75.9, 74.1

Click to expand...

I found that my cells balanced very well even when only charging to full occasionally (about once a month) what is your mileage?

I have screen shot of last full charge the first week of August at 9867 miles. Unlike some, my odometer issues were reported to Jim several months ago and his next update fixed it. The screen shot shows 96.25% and now, 650ish miles later, its 96.16 so the numbers are dropping but gradually.

http://daveinolywa.blogspot.com/2018/08/2018-leaf-6-month-review.html

I still have to update to fix the odometer issue. I think I have about 900 miles on the car, about 700 of them from me driving it.

I also got 2 major drops in SOH on my 2018 Nissan Leaf within the last 6 months of ownership. I lost 2 percent in mai and another 1.5 percent in august. I am living in norway and the car was parked in a garage when the drops happened. So heat can't be an issue.
My leaf has driven 15000km so far and got only one QC during the last 6 months.

Those are my latest readings:
SOH: 95.04%
@ 15400km

If this rapid degradation continues, I will be down to 66% within 3 1/2 years or 100.000km.

There is usually more drop in the first year of a lithium battery's life than later years, but 5% is too much if it extends out to 10% annual. Either there is another "BMS Error" in the 40kwh packs, or they are living up to the nickname "Lettuce Pack."

It's about time to check mine again, but we're in a heatwave yet again, and I don't want to charge to 100%. Maybe I'll read it at the 70% or so it's at now.

mdeekay said:

I also got 2 major drops in SOH on my 2018 Nissan Leaf within the last 6 months of ownership. I lost 2 percent in mai and another 1.5 percent in august. I am living in norway and the car was parked in a garage when the drops happened. So heat can't be an issue.
My leaf has driven 15000km so far and got only one QC during the last 6 months.

Those are my latest readings:
SOH: 95.04%
@ 15400km

If this rapid degradation continues, I will be down to 66% within 3 1/2 years or 100.000km.

Click to expand...

At least you are on pace for a warranty replacement. I am on pace now to have 33% degradation at 100,000 miles so I will just miss it.

Re: 2016 30 kWh Battery data
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Tue Sep 04, 2018 11:46 pm

I bought my 2018 Leaf on Aug 25. We live in New Hampshire and ended up doing a little 1200 mile road trip this last week to break the car in which brought us to all 6 New England States and New York State. The weather was quite hot, 90+ degrees most days. The car did better than I had personally expected. I didn't buy this car to take road trips in. Essentially I bought it for winter commuting. However it did quite well for 250 mile days though after 2 DCQC the battery temps were 120+F on those days. Keep in mind those days incurred 70mph highway speeds at summer temps. For the cars price point ( sub $20k after Tax Credit) I think it's a fantastic vehicle. Anyhow here are Leaf Spy numbers the day I brought it home and after returning from the 1200 mile trip.

8/26/18
SOH 98.41
Hx 98.12
AHr 113.604

9/2/18 after 1200 miles
SOH 98.34
HX 101.76
AHr 113.524

Worth noting that in between those two samples the following was recorded around 1000 miles showing that numbers dipped and then increased. Which is sort of interesting.
SOH 98.22
HX 101.35
AHr 113.466

Doing QCs tends to improve the stats. It will be interesting to see if they stay good, or if they drop in the next few weeks.

Hi Guzziboy,

On those 250 mile hot summer trips, do you remember how long each of your DCQC sessions took? What SOC did you charge to? And how many miles did you drive between these two DCQC sessions?

Also, I saw on another thread that a local Nissan dealer had messed up your sub-20K Leaf deal, and you had walked. But it looks like it worked out after all? So does that mean that the discounts in question can indeed be combined?

Thanks.

Regarding the purchase of the vehicle. The first deal fell through when I went to pick up the car the dealer discovered that Nissan wasn’t going to reimburse them for the stacked utility rebate. They pushed a lease on me and I declined. I reached a deal with an out of state dealer for same package level (SV) for $27,000 which included a college degree rebate of $1000 that I didn’t know I had coming. Anyhow while we were driving to pick up the car the first dealer called me and ended up matching the price after some bellyaching (and continuing to push the lease).

Here is the list of QC from EVGO during my trip. Keep in mind there was level 2 charging done at the hotels also. Honestly SOC was all over the map during charging based on where I was and where I needed to be. SOC varied from 10% to 50%. Our longest single day was 285 miles. I think anymore than that and QC charging would really start to be limited on speed. But To be honest we weren’t really affected by charge rates to that point as 30 min breaks were welcome.

Quechee VT.
24 min. 12.2kwh
Sturbridge, MA.
24min 7.8 kWh
37 min 17.7 kWh
Salem, NH
10 min 4.5 kWh
30min 14.5 kWh
20min 7.4 kWh
31min 15.2

I actually found the QC was taking .01 or more chunks from the SOH and that after I got home and trickle charged the car the SOH went up. It may be an anomaly.

Interesting to see that it is possible for stats to go up. It hasn't happened to me but right now I am almost exclusively fast charging so will see how things change this Winter when I start charging more at home again.

LeftieBiker said:

Doing QCs tends to improve the stats. It will be interesting to see if they stay good, or if they drop in the next few weeks.

Click to expand...

It will be interesting to see because the car will be used for short commuting trips in the coming weeks whenever the temps start dropping. I was pretty impressed that the 150 mile range was very accurate even with 90% highway use. Averaged 4.2 miles/kWh in 1200 miles. Around town I can see the range being much higher.