Topping up to 12 bars

[bowthom]

Hello Leafers,
One way I thought might help us determine battery degradation is tracking how much energy it requires to top up the battery from 10 to 12 bars. I went through all of my tracking documents and compiled this list for my Leaf. The timer is set to 80% (83% according to carwings) and after it stops I press the timer bypass button and top up the battery. Something we do regularly in the morning just before we leave.

These readings are from the wall so topping up only takes ~3.7 kWh to 100% charge now.

April 2011: reprogramming recall P1213 done
May 2011: 5.3, 5.4, 5.3
Charger Replaced – Leaf at dealer May 25th thru June 9th
June 2011: 5.4, 4.8
July 2011: 4.8,
August 2011: No usable data, reporting from carwings and Blink 60% fail.
September 2011: 4.8, 4.1, 4.8
October 2011: No usable data, reporting from carwings and Blink 45% fail.
November 2011: No usable data, reporting from carwings 40% and Blink 70% fail.
December 2011: No usable data, leaf timer not working and/or not set.
January 2012: 4.729, 4.718
February 2012: Did not charge to 12 bars
March 2012: Did not charge to 12 bars
April 2012: 4.993, 4.487, 4.425
May 2012: 4.362, 3.276, 4.104, 4.059
June 2012: 4.252
July 2012: 3.466, 3.672
August 2012: 3.691, 3.781, 3.755, 3.870, 3.896, 3.596, 3.642
September 2012: 3.913, 3.908, 3.537, 3.964, 3.505

The trend

 

[adric22]

The only problem I see is that how do you know you are at exactly 10 bars? What if you are at 10.5 bars? There just isn't enough accuracy there.

However - your idea has merit. If you wanted to run your Leaf all the way down to Turtle and then charge it up on 120V using a kill-a-watt meter you could get a basis for comparison with other Leafs that do the same experiment.

 

[kolmstead]

Sure doesn't seem to cycle with seasonal temperature, does it? Some folks think we're going to gain capacity as ambient temperature decreases. I expect the opposite.

-Karl

 

[bowthom]

Well, it's not exactly 10 bars BUT the Leaf charger is controlling when it shuts off while charging to 80% with the timer set. So that should be pretty consistent.

Karl, I always loose capacity when the battery temp falls to 4 bars during the winter plus my range is further reduced by using the heater.

 

[edatoakrun]

Hello Leafers,
One way I though might help us determine battery degradation is tracking how much energy it requires to top up the battery from 10 to 12 bars. I went through all of my tracking documents and compiled this list for my Leaf. The timer is set to 80% (83% according to carwings) and after it stops I press the timer bypass button and top up the battery. Something we do regularly in the morning before just we leave.

These readings are from the wall so my top 2 bars only takes ~3.7 kWh to charge now.

April 2011: reprogramming recall P1213 done
May 2011: 5.3, 5.4, 5.3
Charger Replaced – Leaf at dealer May 25th thru June 9th
June 2011: 5.4, 4.8
July 2011: 4.8,
August 2011: No usable data, reporting from carwings and Blink 60% fail.
September 2011: 4.8, 4.1, 4.8
October 2011: No usable data, reporting from carwings and Blink 45% fail.
November 2011: No usable data, reporting from carwings 40% and Blink 70% fail.
December 2011: No usable data, leaf timer not working and/or not set.
January 2012: 4.729, 4.718
February 2012: Did not charge to 12 bars
March 2012: Did not charge to 12 bars
April 2012: 4.993, 4.487, 4.425
May 2012: 4.362, 3.276, 4.104, 4.059
June 2012: 4.252
July 2012: 3.466, 3.672
August 2012: 3.691, 3.781, 3.755, 3.870, 3.896, 3.596, 3.642
September 2012: 3.913, 3.908, 3.537, 3.964, 3.505

The trend

Sure doesn't seem to cycle with seasonal temperature, does it? Some folks think we're going to gain capacity as ambient temperature decreases. I expect the opposite.

-Karl

Thank bowthom.

Actually, I see almost all the reduction from May to July (when many mild-climate gid counters saw reductions, IIRC) but kind of bumpy data reporting doesn't show up so well on the horizontal axis.

What sort of ambient/battery temps do you estimate during charge time, bowthom?

Ever get only nine bars from "80%" charge yet?

 

[DaveEV]

I have seen some variation here as well. But I don't charge as often to 100% as you - and always use the timer override with minimal time spent sitting at 100%. All data recorded by Blink - kWh and time.

1/8/2012: 4.959 1:28
3/11/12: 4.667 1:24
4/28/12: x.xxx 1:14 (no Blink data, going off charge start/stop emails)
5/24/12: 4.379 1:14
6/24/12: 4.247 1:13
7/8/12: 3.959 1:07
7/12/12: 4.847 1:21

Haven't charged to 100% since then. But look at the big jump I had after charging to 100% within a week in July. Presumably this was due to the pack being out of balance. I suspect that logging power draw would be much more enlightening.

Here's another data point to look at when charged to 80% - log onto carwings (either website or phone) and check the time to charge to 100%.

This morning my car reported 3:30 to trickle up to 100% and 1:30 to L2 up to 100%.

Surfingslovak's reverse range chart indicates that a new car should report 4:30 to trickle up to 100%.

It looks like bowthom has been charging enough to 100% recently that pack balance shouldn't be much of an issue here...

 

[bowthom]

Hello,
I'm not too sure. First we top up and leave as you do. Rarely does the car spend 4 hours to do a balancing while plugged in at 100% and when I have done that specifically so the car will do a balancing routine, I have not seen any indication that it has done so. My last bar of battery is pretty squirrely so my cells are not very equal down there at the bottom either.

ED: Still at 10 bars @ 80% and battery bars @ 12.
6 bars of battery temp during the summer and during my spring Eugene EVenture DCQC events.
5 bars during the spring and fall.
4 bars during the winter.

 

[mkjayakumar]

In general I have also noticed that the charging to 80% happens approx 10 to 15% sooner than what the Carwings says. If it says it would take 12 hours to charge, the charging stops at around 10 1/2 hours. Whereas when it was new, that difference was less than 15 minutes.

 

[nogajim]

I am still getting 10 bars at 80% charge, but the GID meter is down to 72.2%. I am really hoping for some uptick with cooler evening temperatures.

 

[DaveinOlyWA]

at first glance it seems like your results are backwards. we all know when its colder out, the pack will not take a charge as well as when its 80. my cold weather test (full to turtle) indicated about 19.5 KW available when in Summer it says I should have 21.2 or so.

so i guess the big question is the reduced charge capacity off the top or bottom? i would think it would be the top since the higher resistance of a cold pack would increase voltage and trick the BMS into thinking the pack is fuller than it is?

 

[mwalsh]

at first glance it seems like your results are backwards. we all know when its colder out, the pack will not take a charge as well as when its 80. my cold weather test (full to turtle) indicated about 19.5 KW available when in Summer it says I should have 21.2 or so.

so i guess the big question is the reduced charge capacity off the top or bottom? i would think it would be the top since the higher resistance of a cold pack would increase voltage and trick the BMS into thinking the pack is fuller than it is?

If you check TickTock's commute spreadsheet on Google Drive, it looks like he got a fairly good Gid uptick come cooler (AZ) weather last fall. I guess that's what we're counting on.

I happened to do an 80% charge yesterday and then topped off to 100% manually some hours later. I'm also getting around 71% on an 80% charge, versus something like 83% last fall. Now I'm not saying I expect to get that, or 281 on a 100% charge, again. But TickTock's results seem to indicate a possible 10 Gid bump, or ~4% SOC, which will put me back into 100% territory I was seeing in the early summer.

 

[bowthom]

Hello,
Wish I could test for GID's but I'm still waiting on my "LeafScan."

 

[bowthom]

In general I have also noticed that the charging to 80% happens approx 10 to 15% sooner than what the Carwings says. If it says it would take 12 hours to charge, the charging stops at around 10 1/2 hours. Whereas when it was new, that difference was less than 15 minutes.

I have noticed this as well, although, pretty much from when it was new. I don't think the charge times follow the battery capacity.

 

[DaveEV]

I have another data point today after charging to 100% for the first time since July 9:

1/8/2012: 4.959 1:28
3/11/12: 4.667 1:24
4/28/12: x.xxx 1:14 (no Blink data, going off charge start/stop emails)
5/24/12: 4.379 1:14
6/24/12: 4.247 1:13
7/8/12: 3.959 1:07
7/12/12: 4.847 1:21
9/30/12: 4.509 1:13

Now here's what's interesting. I decided to start charging again about 15 minutes before I left to see if I'd be able to sneak in a bit more energy thanks to any balancing that might have occurred. Charging had stopped 41 minutes before I started it again.

It charged for 11 minutes before I had to leave (it was still charging) and the Blink reported 0.413 kWh (how much longer would it have run? - who knows).

That would bump the charge to 1:24 and 4.922 kWh.

This morning charging to 80% stopped at 9/12 bars - it's been doing that intermittently since middle of August.