Eddie16
Posts: 1
Joined: Fri Aug 21, 2020 1:06 pm
Delivery Date: 21 Aug 2020
Leaf Number: 312338
Contact: Twitter

charge rate affects battery degradation?

Tue Nov 17, 2020 5:20 pm

This post poses questions about battery degradation/replacement, and
offers a warning to other users of the Leaf 30KWH battery, about charging
strategy. Battery degradation in the Leaf I own appears to be charging-
related:

Sep 2019 Purchased a used 2016 Leaf with 29K miles and a 30KWH
10-bar battery. It was previously owned by a woman, from
which I have assumed that the vehicle was likely charged
only with a 120V charger at ~15A (1.8KW).

Mar 2020 Purchased a 240V 10A/16A/32A charger for faster turnaround.
Set charger to 16A, which provides an indicated charge rate
of 3.5KW. Assumed this would be OK, as Nissan's manual says
3KW is OK for frequent charging, and 6KW should be used
only occasionally.

Jun 2020 My mechanic noted that the battery had dropped to 9 bars.

Oct 2020 I noted the battery had dropped to 8 bars. Switched
charging down to 10A (indicated charge rate 2.1KW).

Nov 2020 The vehicle is now at 35K miles. I figure I got about 3000
miles out of it, before battery degradation began.

This vehicle has been babied, otherwise. Garaged 95% of the time. Never
driven when ambient temperature is over 90F (yes, I knew when I bought it
that the battery is air cooled). I don't floor it except when being crowded
upon entry to a parkway/freeway. The battery temp gauge has been watched;
it has gone up to 4 bars within the normal range only a few times, and has
been at 2 or 3 bars within the normal range, most of the time. I also noted
that the drop from 10 to 9 points, occurred in late winter/spring, when I
began charging at 3.5KW, but ambient temperatures in Colorado were still
pretty low at that time.

I checked the web about this and immediately noticed a couple things. The
primary factors affecting Leaf battery life are (1) the conditions under
which it is driven, esp. temperature, and (2) how it is charged. I also
noted articles claiming that the 30KWH battery has faster degradation,
than the 24KWH battery.

My questions are:

1. Has anyone correlated 30KWH battery degradation with ~3KW charging?
2. Does anyone know if the later Nissan batteries (40KWH and 62KWH) are
engineered for better heat transfer, and have lower degradation rates,
than the 24KWH or 30KWH batteries?
3. Does the configuration/physical size of the 40KWH battery, allow it to
be installed in 2011-2017 Leafs?
4. Has anyone out there dealt directly with Nissan on the issue of battery
degradation, and received any satisfaction, for batteries degraded less
than 4 bars?
5. Has anyone found any business, other than Nissan dealers, which does
battery replacement? I checked NissanLeafBatteryReplacement.com, but
the only shop in Colorado on their list, still isn't doing replacement.

LeftieBiker
Moderator
Posts: 15742
Joined: Wed May 22, 2013 3:17 am
Delivery Date: 30 Apr 2018
Location: Upstate New York, US

Re: charge rate affects battery degradation?

Tue Nov 17, 2020 6:09 pm

Others will chime in with more, but the bullet points are:

* There is a known issue with the 30kwh packs. Nissan claimed at first that it is just a software issue, and has a Battery Management System (BMS) update for the cars with 30kwh packs.

* It is NOT just a software issue. Many of the affected packs are suffering from real accelerated degradation. The only real way to find out is to get the update, which will temporarily raise the capacity display to 12 bars in all cases, and then see how many bars go away again.

* The cars are still under their 8 year, 100,000 mile battery warranty, and Nissan is installing 40kwh packs as warranty replacements. You must first get the BMS update to qualify for a warranty replacement.
Scarlet Ember 2018 Leaf SL W/ Pro Pilot
2009 Vectrix VX-1 W/18 Leaf modules, & 3 EZIP E-bicycles.
BAFX OBDII Dongle
PLEASE don't PM me with Leaf questions. Just post in the topic that seems most appropriate.

GerryAZ
Gold Member
Posts: 2631
Joined: Mon Nov 22, 2010 6:47 pm
Delivery Date: 12 Jun 2011
Location: Phoenix, AZ

Re: charge rate affects battery degradation?

Tue Nov 17, 2020 8:11 pm

My 2015 was charged at the maximum L2 (240-volt) rate of about 6 kW for the entire time I owned it and my 2019 is charged the same way. In my opinion, the degradation you see is not related to L2 charging. Since it is down to 8 capacity bars, you should see your dealer about a battery replacement under warranty.
Gerry
Silver LEAF 2011 SL rear ended (totaled) by in-attentive driver 1/4/2015 at 50,422 miles
Silver LEAF 2015 SL purchased 2/7/2015; traded 8/10/2019 at 82,436 miles
White LEAF 2019 SL Plus purchased 8/10/2019

SageBrush
Posts: 5377
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: NM

Re: charge rate affects battery degradation?

Tue Nov 17, 2020 8:59 pm

OP, cut to the chase:

1. Get the BMS update through a Nissan dealership. It is free
2. The car capacity bars will increase due to a reset that is part of the update and then settle down to its real capacity when calibration is complete.
3. When the capacity drops to 8 bars from ongoing or already present degradation, if you are still within the battery degradation warranty period and miles you are likely to get a 40 kWh battery replacement
4. Be happy

3/6 kW charging has nothing to do with battery degradation
If your garage is hot and unventilated, it is cooking your LEAF battery
2013 LEAF 'S' Model with QC & rear-view camera
Bought Jan 2017 from N. California
Two years in Colorado, now in NM
03/18: 58 Ahr, 28k miles
11/18: 56.16 Ahr, 30k miles
09/20: 54.3 Ahr; 38k miles
-----
2018 Tesla Model 3 LR, Delivered 6/2018

alozzy
Posts: 1645
Joined: Fri Jan 20, 2017 4:25 pm
Delivery Date: 18 Jan 2017
Location: Vancouver, BC
Contact: Website

Re: charge rate affects battery degradation?

Tue Nov 17, 2020 11:27 pm

It seems you are located in Colorado, which is surprising given the apparent 8 remaining capacity bars shown on the dash. A drop of 2 bars over a year (Sep 2019 to Oct 2020) is abysmal, as that represents at least a 15% drop in the SOH. Even if you L2 charge to 100% every night, or do frequent L3 charging, degradation shouldn't be that bad in your climate.

For sure, you should go to a Nissan dealership and have the BMS update done as some of this apparent loss is likely due to the BMS software bug. After the BMS update, I would hope that your real SOH will be closer to 80% - only one way to find out...

You should also purchase an OBD2 dongle and install LeafSpy on your cell phone. More details here:

https://www.youtube.com/watch?v=6yS-5HMYUHc

Without it, you really don't have any insights into the state of the battery pack.
Vancouver, CA owner of a 2013 Ocean Blue SV + QC, purchased 01/2017 in WA
Zencar 12/20/24/30A L1/L2 portable EVSE
1-1/4" Curt #11396 hitch
After market, DIY LED DRLs
LeafSpy Pro + Konnwei KW902 ELM327 BT OBDII dongle
Loving my first BEV :D

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