The 40KWH Battery Topic

[DougWantsALeaf]

Maybe they are downrating it to hit 70% at exactly 8 years.. and by managing it, making the range curve more predictable across cars.

[danrjones]

Which raises an interesting question- are ev makers allowed to artificially derate your battery? Obviously they are held to the warranty, but anything else?

[golfcart]

I haven't seen that big 3 month drop. I had a decent sized drop from May to June after getting the car in mid-march but no corresponding August to September. I'll keep checking every month and post my results.

Date SOH% SOH %Chg Ahr Ahr %Chg TempF

3/15/19 97.47 -2.53% 112.52 -2.53% 69.1
4/15/19 97.41 -2.59% 112.45 -2.59% 75.2
5/15/19 97.34 -2.66% 112.37 -2.66% 82.2
6/15/19 95.38 -4.62% 110.11 -4.62% 90.8
7/15/19 94.98 -5.02% 109.64 -5.02% 97
8/15/19 94.63 -5.37% 109.24 -5.37% 101.8
9/15/19 94.41 -5.59% 108.99 -5.59% 92.2

[danrjones]

It looks like you had one between may and June, but to know for sure you have to almost check daily.

Then again you could have a different bms software version. Who knows!

[DaveinOlyWA]

I haven't seen that big 3 month drop. I had a decent sized drop from May to June after getting the car in mid-march but no corresponding August to September. I'll keep checking every month and post my results.

Date SOH% SOH %Chg Ahr Ahr %Chg TempF

3/15/19 97.47 -2.53% 112.52 -2.53% 69.1
4/15/19 97.41 -2.59% 112.45 -2.59% 75.2
5/15/19 97.34 -2.66% 112.37 -2.66% 82.2
6/15/19 95.38 -4.62% 110.11 -4.62% 90.8
7/15/19 94.98 -5.02% 109.64 -5.02% 97
8/15/19 94.63 -5.37% 109.24 -5.37% 101.8
9/15/19 94.41 -5.59% 108.99 -5.59% 92.2

Holy sheepdip! Hate to see your definition of a big drop...

I would put nothing into these readings. I fear that Nissan has changed BMS programing to thwart LEAF Spy. FYI; the adjustment doesn't always go down.

[golfcart]

I haven't seen that big 3 month drop. I had a decent sized drop from May to June after getting the car in mid-march but no corresponding August to September. I'll keep checking every month and post my results.

Date SOH% SOH %Chg Ahr Ahr %Chg TempF

3/15/19 97.47 -2.53% 112.52 -2.53% 69.1
4/15/19 97.41 -2.59% 112.45 -2.59% 75.2
5/15/19 97.34 -2.66% 112.37 -2.66% 82.2
6/15/19 95.38 -4.62% 110.11 -4.62% 90.8
7/15/19 94.98 -5.02% 109.64 -5.02% 97
8/15/19 94.63 -5.37% 109.24 -5.37% 101.8
9/15/19 94.41 -5.59% 108.99 -5.59% 92.2

Holy sheepdip! Hate to see your definition of a big drop...

I would put nothing into these readings. I fear that Nissan has changed BMS programing to thwart LEAF Spy. FYI; the adjustment doesn't always go down.

I haven't seen that big 3 month drop

I had a big drop from May to June, did not see one 3 months later from August to September... unless you consider going from 109.24 Ahr to 108.99 Ahr a big drop.

You had posted this back in July that you expected updates to happen every 90 days... which I did not see.

No rush. Adjustments come every 90 days. You can simply wait till Sept. I will say a .15-.25% loss in July with same for August...

[danrjones]

Which one doesn't always go down?

My Hx doesn't always go up. It just ticked down very slightly the last two days. SO FAR my SOH always has gone down.

But I agree, its all so artificial, I think its a BMS software thing more than real battery degradation.
It did cause me to ask if Nissan, or any company for that matter, has the right to artificially reduce your battery life.
I pointed out apple was caught doing essentially that to phones.

I have a nice plot of my SOH including the two drops but I guess I can't directly post it.

It also makes me wonder if the SOH we are all watching in leafspy is even a good measure of the battery health bars in the 2018/2019s.
I tried finding the battery health bar in the the manual to see what they said about it and actually couldn't find it. It seems it was only called out by name in the warranty.

[LeftieBiker]

Which one doesn't always go down?

With previous generation battery packs, the SOH will go up occasionally, like after a QC session. We do have one lonely instance of a 40kwh pack SOH going up - a little, once.

[DaveinOlyWA]

Which one doesn't always go down?

My Hx doesn't always go up. It just ticked down very slightly the last two days. SO FAR my SOH always has gone down.

But I agree, its all so artificial, I think its a BMS software thing more than real battery degradation.
It did cause me to ask if Nissan, or any company for that matter, has the right to artificially reduce your battery life.
I pointed out apple was caught doing essentially that to phones.

I have a nice plot of my SOH including the two drops but I guess I can't directly post it.

It also makes me wonder if the SOH we are all watching in leafspy is even a good measure of the battery health bars in the 2018/2019s.
I tried finding the battery health bar in the the manual to see what they said about it and actually couldn't find it. It seems it was only called out by name in the warranty.

My SOH and ahr has either stayed the same or went down EVERY TIME except my July adjustment when they went up gaining 1¼%.

[danrjones]

Which one doesn't always go down?

With previous generation battery packs, the SOH will go up occasionally, like after a QC session. We do have one lonely instance of a 40kwh pack SOH going up - a little, once.

I have this picture in my head of some tech guy as Nissan sitting around laughing at us for watching leafspy every day.

But those battery health bars must be connected to something. When Nissan does a service, what exactly do they print out and give you?
I read here somewhere that someone had a five star battery rating. Is that all you get?