The 40KWH Battery Topic

[danrjones]

To find out if I'm right we would need daily HX readings from a bunch of folks along with their SOC - and maybe not just average SOC, but also max and min. And I could be totally wrong and its all a coincidence. There could also be other factors, such as DC Fast charging, which I don't really do, and temperature could also play a role.

My car last night was sitting at a SOC around 67% and HX went down slightly.

I also should have my next 3 month adjustment any moment.

Current stats:

SOH = 90.04
AHr = 103.94
Hx = 103.58
364.94 V
65.4% SOC

ODO = 8070 miles
10 QC & 388 L1/L2

 

[lorenfb]

Here are my Leaf stats for my 2 Leafs. Both 62s, but I can't figure the Hx.

https://docs.google.com/spreadsheets/d/1mjGg2SdFQzo3_GzA6YY_Ob1MrfkX9hidN2caTR92xAA/edit?usp=drivesdk

Except for SOH and mileage, basically a random number generator.

 

[SageBrush]

Except for SOH and mileage, basically a random number generator.

Ahr ?

 

[DougWantsALeaf]

Does Pack temp st time of measurement matter?

 

[danrjones]

Does Pack temp st time of measurement matter?

Were you asking me?

I have no idea. But HX appears to move slowly, and my temp various quite a bit over a 24 hr period, and i have not seen HX moving over the 24 hr period with temperature.

But in the long run, does temp impact HX? Sure, maybe, who knows.

Does fast charging impact HX? I don't know that either. The last three fast charges I have done were testing the new site near me, and I went from ~ 25% to 50%, and never noticed a jump in HX afterward. But those are pretty minor Fast charge sessions, I think.
Maybe Fast charging impacts HX when you start to charge above the 75% range?

I would be very curious to see the HX of someone who never charges above 75% and never lets it drop below 20% versus someone who charges to near 100% daily?

 

[DaveinOlyWA]

Does Pack temp st time of measurement matter?

Could... This is why I always record measurements before the first drive of the day...most of the time. For days like today; I got up this morning and plugged in as always. Have a few errands to do and probably a large chunk of free time (which has become common lately) so not sure what I will do with that but a 3 hour charge brings me to about 55% which will more than cover my needs likely more than 2X. I will check stats in a few but not likely to leave the house until near noon. My "normal" day consists of plugging in in the morning and unplugging when I leave for work which gives me about 75 minutes of charge time.

Either way, I think setting a sort of schedule to check is best. I have a garage so its easy for me to buzz back and forth. If I was parked outside, I would likely elect to check it when parking for the night instead.

 

[jmurtagh13]

24,300 miles 2 years 9 months. Next month is my recalibration, will it go up or down ?

I'm hoping with the cold weather it goes positive.

 

[DaveinOlyWA]

24,300 miles 2 years 8 months. Next month is my recalibration, will it go up or down ?

I'm hoping with the cold weather it goes positive.

No change. I would highlight your Jan 2020 as green as well since there was no change on that one either. FYI; my only positive reading came in July...

 

[DougWantsALeaf]

I was surprised to see how much his battery warmed in a cold day with the 40 pack. Do others see this too?

I can say the 62 pack doesn't warm nearly as much if at all when its below 50F/10c.

https://youtu.be/M5xT5zEqu18

 

[danrjones]

To find out if I'm right we would need daily HX readings from a bunch of folks along with their SOC - and maybe not just average SOC, but also max and min. And I could be totally wrong and its all a coincidence. There could also be other factors, such as DC Fast charging, which I don't really do, and temperature could also play a role.

My car last night was sitting at a SOC around 67% and HX went down slightly.

I also should have my next 3 month adjustment any moment.

Current stats:

SOH = 90.04
AHr = 103.94
Hx = 103.58
364.94 V
65.4% SOC

ODO = 8070 miles
10 QC & 388 L1/L2

Well, as of this AM I did not get a 3 month update. It should have happened by now if it was going to happen.
My numbers this morning are essentially the same as those above.

So like clockwork I had gotten a 3 month update, then last update was the first time I gained SOH. Then this update did not occur.

 

[goldbrick]

Or the update happened and the adjustment was near 0. Plot the adjustment vs time, it may look like a damped sine wave that has finally died out.

 

[DaveinOlyWA]

To find out if I'm right we would need daily HX readings from a bunch of folks along with their SOC - and maybe not just average SOC, but also max and min. And I could be totally wrong and its all a coincidence. There could also be other factors, such as DC Fast charging, which I don't really do, and temperature could also play a role.

My car last night was sitting at a SOC around 67% and HX went down slightly.

I also should have my next 3 month adjustment any moment.

Current stats:

SOH = 90.04
AHr = 103.94
Hx = 103.58
364.94 V
65.4% SOC

ODO = 8070 miles
10 QC & 388 L1/L2

Well, as of this AM I did not get a 3 month update. It should have happened by now if it was going to happen.
My numbers this morning are essentially the same as those above.

So like clockwork I had gotten a 3 month update, then last update was the first time I gained SOH. Then this update did not occur.

My positive update was followed by a zero update as well. A month later I upgraded to the Plus.

 

[danrjones]

Or the update happened and the adjustment was near 0. Plot the adjustment vs time, it may look like a damped sine wave that has finally died out.

Yes I have it plotted. Last update was a big upward movement for the first time. Dampening down to zero this update is possible but that would be abrupt.

 

[HerdingElectrons]

2018 SL 40kWh with almost 33K miles

09/2019 94.33% SOH at 17K MIles

11/2019: 93.07% SOH at 20K Miles

02/2020: 92.93% SOH at 23K Miles

04/2020: 92.13% SOH at 25K Miles

06/2020: 91.18% SOH at 28K Miles

08/2020: 91.09% SOH at 29K Miles

12/2020: 91.29% SOH at 33K Miles

After the initial 5-6% drop in the 1st 9 months the degradation seems to have really slowed down which is very encouraging relative to what I have read about in the past.

The biggest change I have noticed in practical terms from losing 9% capacity is how much lower the SOC has to be before I have access to full regen ability. When new I had full ability at 82% SOC or lower & now I have to be at 76% SOC or lower to have all of the blue bars on the dash available.

 

[DaveinOlyWA]

The biggest change I have noticed in practical terms from losing 9% capacity is how much lower the SOC has to be before I have access to full regen ability. When new I had full ability at 82% SOC or lower & now I have to be at 76% SOC or lower to have all of the blue bars on the dash available.

Interesting. Not surprised that regen changes parameters of things but surprised to see it so noticeable that early. TBH, I so rarely charged to full, I never noticed.

 

[DougWantsALeaf]

I habe also noticed that at 100% charge my regen (on my 62) has changed from when I first got the car.

I saw a Facebook poster saying they were at 84.x% SoH and still at 12 bars.

My latest thought is that maybe we will be seeing cars in the low 80s before 11 bars if there is in fact a buffer kept by the BMS?? Not sure though how the car dash would know the true stste unless it came over a different diagnostic code? Does anyone know how the number of bars is determined by the car from data sent from the BMS?

 

[LeftieBiker]

I seem to remember reading here that it's thought to be a simple lookup table of fixed values for various inputs, but AFAIK it isn't really known.

 

[DaveinOlyWA]

I habe also noticed that at 100% charge my regen (on my 62) has changed from when I first got the car.

I saw a Facebook poster saying they were at 84.x% SoH and still at 12 bars.

My latest thought is that maybe we will be seeing cars in the low 80s before 11 bars if there is in fact a buffer kept by the BMS?? Not sure though how the car dash would know the true stste unless it came over a different diagnostic code? Does anyone know how the number of bars is determined by the car from data sent from the BMS?

SOH isn't the goto number I use to determine loss of bars. Look at Ahr. On a 40 kwh pack, new ahr is about 115. There does seem to be a bit of buffer that varies but most of them only have about 1% so if I had to predict, I'd say bar loss around 96.6 ahr

The other thing to realize is the bars have a range of turn off values which means its possible for it to be off one day and back on the next. Obviously the "back on" is a temporary and generally short lived event but its happened.

 

[DougWantsALeaf]

It will be curious to see if the bar flips wok the same with the updated BMS/chemistry.

 

[MrSourBalls]

Ok, so my Muxsan-extended Leaf 40, 2018 is about to pass the 100.000km (98984km) mark, and is about 1000 days (1033 at time of posting) on the road so probably a little older than that.

I do about 118.6km a day on average. Charge to 100% 5 times a week at work, and drive home 80km's and leave it with about 75-85% charge, drive back to work 80km's the next day and plugging it in.

Average consumption from the pack over the past 72474km +- 133Wh/km or 156Wh/km from the wall (including pre-heating and charging losses)

Judging by the SOH numbers my Leaf shows, i gather it is a rather linear formula of dry 0,01% per 24h.

Current SOH: 89,91%
Degradation: 10,09%
Days on road: 1033

That is a little bit too close to be a coïncidence for me.
I estimate the actual SOH around 95% judging by the amount of kWh's i can pull from the pack in optimal conditions (about 54-55kWh with the right temperatures. The extender is about 17,6kWh usable, makes 37,4kWh from the main pack, estimating 39k,5Wh when at 100%, gives 94,6% SOH.)

I usually calculate my usable capacity as follows:
(100/<spent % in Leafspy since full>)*(Wh/km from dash*Tripkm's)=Usable capacity.

So it seems to be holding up well. I rarely quick charge (63QC's lifetime, of which at least 30 "failed" sessions because of some bugs while i was betatesting some stuff for Muxsan. So really closer to 30QC's.
And 1099 L2 charges according to Leafspy, but in my own charts i recorded only 392 L2 charges, so the truth must lie somewhere in the middle as i (very rarely) bundle 2-3 short charges in one data point.

My HX numbers are rising, they reached a low point of about 92 around 90.000km (beginning of october 2020). Now around 96 and plateau-ing.
HX Peaked at 107% at 51.000km (december 2019) slowly delclining to 92 since then and now rising.

With the extenderpack i notice no / very little effect on the reported SOH and its decline which seems like it can't be true. The pack heats noticeably slower with temperatures not going very far above ambient + 1-2degrC unless i hammer it. The reported temperatures are much closer to eachother, most of the times within 1-2 degrees C.
I have been driving with the extender for 37.684km. So about since 60.000km on the ODO.

I project 70% reported SOH of the main pack around 291.032km (or in 1981days / 5 years 156 days) ODO, based on a linear extrapolation of the current SOH data provided by Leafspy. .0001019
Going off the calculated numbers of 94,6% remaining SOH now at 100.000km and 1000 days:
0,0054% per day or 0,000054 per km means 70% SOH at 554.409km or in 4555 days (12 years 175 days), probably a little optimistic, but would be fantastic if true .