ixnay
Posts: 5
Joined: Mon Jan 22, 2018 11:21 pm
Delivery Date: 17 Feb 2018
Leaf Number: 317056

Re: Capacity Loss on 2011-2012 LEAFs

Sat Feb 10, 2018 11:04 pm

I picked up a 2011 Ocean Blue SL with 0,000 miles last month, now 30,716 (so I'm driving double the former owner's monthly average)
According to LeafSpy Pro
166 GIDs
AHrs = 48.18;
SOH - 73.45
After last night's 80% charge, current SOC 78.1 (in part because I was detailing it today and had it powered on for a bit)

Bottom line: with my current efficiency, I can drive around 40 miles, getting 4.1-2/kWh. The GOM says 10 bars and 56 miles (was 58 at end of charge).

User avatar
RegGuheert
Posts: 5867
Joined: Mon Mar 19, 2012 4:12 am
Delivery Date: 16 Mar 2012
Leaf Number: 5926
Location: Northern VA

Re: Capacity Loss on 2011-2012 LEAFs

Mon Feb 12, 2018 6:21 am

RegGuheert on December 14, 2017 wrote:Capacity degradation on our LEAF is now accelerating, with 2.6 Ah lost between 40,000 and 50,000 miles while we only lost 2.2 Ah between 30,000 and 40.000 miles. That is true even though the vehicle was driven those last 10,000 miles over a shorter period of time, so calendar losses during that last period should have been a bit lower.
So now I'm not so sure. As I reported previously, our LEAF has been showing increasing Ah readings recently. Since crossing 50,000 miles on December 7, 2017, at 47.21 Ah, the reported capacity has increased to 48.24 Ah on Februrary 11, 2018, with about 52,000 miles on the odometer.

So, has capacity loss accelerated from 2.2 Ah/10,000 miles (30,000 mi. to 40,000 mi.) to 2.6 Ah/10,000 miles (40,000 mi. to 50,000 mi.) or has it slowed to 1.6 Ah/12,000 miles (40,000 mi. to 52,000 mi.) or both?

Beats me, but I have a new theory about why the capacity has been increasing as of late. I think the BMS may be responding to our efforts to charge the battery to higher SOCs this winter by pressing the timer override button one or more times after the battery has completed its normal charge cycle. We started doing this because the combination of battery degradation (with the associated loss/reduction of regen), new tires and colder temperatures have made my wife's 50-mile commuted quite marginal this winter, even at temperatures of 20 degrees or more. Pressing the timer override button really DOES add more charge to the battery and I think the BMS interprets that as the battery having more capacity.

If that theory is correct, then I suppose when Spring comes around, we will get rapid reported capacity loss due to three different effects: 1) Loss of capacity due to no longer pressing the timer override button, 2) Loss of reported capacity as it warms up (It does that every year!), and 3) Loss of capacity that has been going on all along that has been masked by pressing the button.

We'll see. Perhaps the capacity loss reported over the 50,000- to 60,000-mile interval will shed some light on what is actually happening.
RegGuheert
2011 Leaf SL Demo vehicle
10K miles: Apr 14, 2013, 20K miles (55.7Ah): Aug 7, 2014, 30K miles (52.0Ah): Dec 30, 2015, 40K miles (49.8Ah): Feb 8, 2017, 50K miles (47.2Ah): Dec 7, 2017.
Enphase Inverter Measured MTBF: M190, M215, M250, S280

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