2013 Low Battery Capacity AHr Battery Degradation

[DaveEV]

A Washingtonian just made a road trip that included some QCs and his ahr jumped from 60ish to the low 65's. I personally think (which means I have no proof) that the BMS is adaptive to the user's needs meaning when it senses the user is needing more range, it adjusts the charging parameters using a flexible portion of the pack that is not normally charged at the top end.

Unless you have actual proof of available capacity changing, this is simply an example of the LBC changing it's learned parameters based on different usage patterns.

Another example of the LBC doing this is the rise in capacity levels in cold weather compared to hot.

Unless you fully discharge and charge a pack, one can only make educated guesses as to the actual capacity, and I can guarantee that the Washingtonian's pack did not change 10% in capacity on one road trip.

Moral of the story - on the 2013+ LEAFs especially which show large jumps in reported capacity, take the LBC reported capacity levels with a large grain of salt.

 

[bradbissell]

Looks like I am finally suffering some degradation in the cool northeast climate.

2013 SV built and delivered 3/13.

Readings 9/31/15
AHr: 61.52
SOH: 94%
Hx: 94.84
Gids @ 100% = 267
ODO: 34,700 miles

 

[o00scorpion00o]

Looks like I am finally suffering some degradation in the cool northeast climate.

2013 SV built and delivered 3/13.

Readings 9/31/15
AHr: 61.52
SOH: 94%
Hx: 94.84
Gids @ 100% = 267
ODO: 34,700 miles

I bet if you use the DC charger a few times to 80+% that will climb back up.

I noticed using the 6.6 kw work charge point my gids have climbed back up, doesn't seem to happen on 3.5 kw ? Last night back to 284 gids as new.

 

[dgpcolorado]

Unless you have actual proof of available capacity changing, this is simply an example of the LBC changing it's learned parameters based on different usage patterns.

Another example of the LBC doing this is the rise in capacity levels in cold weather compared to hot.

Unless you fully discharge and charge a pack, one can only make educated guesses as to the actual capacity, and I can guarantee that the Washingtonian's pack did not change 10% in capacity on one road trip.

Moral of the story - on the 2013+ LEAFs especially which show large jumps in reported capacity, take the LBC reported capacity levels with a large grain of salt.

Well said. I see fluctuations all the time that seem to be temperature dependent. This is to be expected with a chemical battery since temperature alters the parameters the LBC is trying to read. As does something like discharge/charge rates, which can temporarily alter the chemistry and measured voltage somewhat.

 

[bradbissell]

Sadly my current SV does't have a Chademo port. I won't make that mistake on my next car.

 

[dgpcolorado]

Sadly my current SV does't have a Chademo port. I won't make that mistake on my next car.

I suppose it depends on where you live. My car doesn't have the Chademo port either and almost four years after I bought it the nearest Chademo station remains 300 miles away, as expected. No regrets here.

 

[asimba2]

It has been a HOT summer in the central valley of California, with quite a few days over 100 degrees, but not much has changed in the past 4.5 months:
06/17/2015 - 15,769 mi - 58.64 Ahr - 89% SOH - 89.04% Hx
07/13/2015 - 16,540 mi - 58.11 Ahr - 88% SOH - 87.89% Hx
08/12/2015 - 17,416 mi - 58.26 Ahr - 89% SOH - 88.22% Hx
08/27/2015 - 17,953 mi - 58.36 Ahr - 89% SOH - 88.45% Hx
09/29/2015 - 18,892 mi - 58.31 Ahr - 89% SOH - 88.33% Hx
10/20/2015 - 19,382 mi - 57.84 Ahr - 88% SOH - 87.31% Hx
10/29/2015 - 19,652 mi - 57.99 Ahr - 88% SOH - 87.64% Hx

All the above numbers were taken at various state-of-charges, usually 80%, so not much cell balancing has occurred. I have never had the opportunity to quick charge (they are always being hogged), so I suspect if I charged to 100% more often or did a few QCs I could get some capacity back. I have not noticed any reduction in range since new, and it is something I track fairly closely.

An apparent loss of 0.6 amp hours over 5 months including a very hot summer isn't as bad as I was expecting, however 11.5% degradation in 2 years is more than I would like to see. Remaining capacity at the end of my three year lease will help me determine if I would purchase an EV without a liquid cooled pack. And before you start touting the lizard pack, there are several guys with 2015 models that are already down to 58 Ahrs just like my 2013.