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Re: 1 gid *mostly* equals 80Wh

Posted: Sun Aug 12, 2012 10:27 am
by TickTock
OK. I did see some temperature dependance on the gid unit. I added two more sets to my plot 0 to 100 and 0 to 80 wall energy. For these, I compute the wh/gid=delta_wall_power/delta_gids then multiply that by the final gid value to approximate the wall power required to go from zero to 80% or 100% charge. When I do this, the seasonality almost disappears and the loss over time is more gradual. Full disclosure: I did delete a few anomalous datapoints that were far off the trend. I am attributing those to days I ran the climate control to pre-heat/pre-cool the car and/or topped off away from home. I am missing a huge chunk of data for this computation during the winter (I got lazy and was only recording data in the morning so don't know what the starting gid value was).

Definitely much less alarming degradation than looking at gid count alone. I can now see why Nissan didn't want us looking at it.

Re: 1 gid *mostly* equals 80Wh

Posted: Sun Aug 12, 2012 10:49 am
by DaveinOlyWA
can you provide a rough chart on capacity verses temp as a guideline? i realize that without knowing time frames that are needed for any real BMS change to occur, the data will be all over the map but i think you have really got something here

Re: 1 gid *mostly* equals 80Wh

Posted: Sun Aug 12, 2012 10:50 am
by edatoakrun
="TickTock"

OK. I did see some temperature dependance on the gid unit. I added two more sets to my plot 0 to 100 and 0 to 80 wall energy. For these, I compute the wh/gid=delta_wall_power/delta_gids then multiply that by the final gid value to approximate the wall power required to go from zero to 80% or 100% charge. When I do this, the seasonality almost disappears and the loss over time is more gradual. Full disclosure: I did delete a few anomalous datapoints that were far off the trend. I am attributing those to days I ran the climate control to pre-heat/pre-cool the car and/or topped off away from home. I am missing a huge chunk of data for this computation during the winter (I got lazy and was only recording data in the morning so don't know what the starting gid value was).

Definitely much less alarming degradation than looking at gid count alone. I can now see why Nissan didn't want us looking at it.[/
And I still don't understand your method of calculating final gid value , TickTock.

Please explain.


Definitely much less alarming degradation than looking at gid count alone. I can now see why Nissan didn't want us looking at it.[/quote]

What degradation?

Doesn't this mean you believe that your battery may be accepting nearly the same kWh from the wall now, at both 80% and 100%, as it was when you began tracking it, on 10/01/2011?

Re: 1 gid *mostly* equals 80Wh

Posted: Sun Aug 12, 2012 12:38 pm
by vegastar
Tick Tock extrapolates the total energy from the wall from 0 to 80% or 100% by calculating the Wh/gid used in each charge session.

I noticed that in my case the value varies a lot. Sometimes the Wh (from the wall) per gid is BELOW 80. In 100% charges the value is always higher than on 80% charges.

Here is my data:

https://docs.google.com/spreadsheet/ccc ... GNJUlFIUmc

Re: 1 gid *mostly* equals 80Wh

Posted: Sun Aug 12, 2012 1:52 pm
by RegGuheert
Thanks for the data, vegastar!
vegastar wrote:I noticed that in my case the value varies a lot. Sometimes the Wh (from the wall) per gid is BELOW 80. In 100% charges the value is always higher than on 80% charges.
I think that is to be expected since the LEAF does cell balancing at the top end. The result is that there will be additional energy dissipated in shunts during 100% charges.

Re: 1 gid *mostly* equals 80Wh

Posted: Sun Aug 12, 2012 2:11 pm
by TickTock
edatoakrun wrote:
="TickTock"

OK. I did see some temperature dependance on the gid unit. I added two more sets to my plot 0 to 100 and 0 to 80 wall energy. For these, I compute the wh/gid=delta_wall_power/delta_gids then multiply that by the final gid value to approximate the wall power required to go from zero to 80% or 100% charge. When I do this, the seasonality almost disappears and the loss over time is more gradual. Full disclosure: I did delete a few anomalous datapoints that were far off the trend. I am attributing those to days I ran the climate control to pre-heat/pre-cool the car and/or topped off away from home. I am missing a huge chunk of data for this computation during the winter (I got lazy and was only recording data in the morning so don't know what the starting gid value was).

Definitely much less alarming degradation than looking at gid count alone. I can now see why Nissan didn't want us looking at it.[/
And I still don't understand your method of calculating final gid value , TickTock.

Please explain.


Definitely much less alarming degradation than looking at gid count alone. I can now see why Nissan didn't want us looking at it.[/quote]

What degradation?

Doesn't this mean you believe that your battery may be accepting nearly the same kWh from the wall now, at both 80% and 100%, as it was when you began tracking it, on 10/01/2011?
Vegastar summed it up pretty well. It looks like I am down 6-8% from when I started tracking last October but I was already down 10-12% by then (why I bought a gid-o-meter and started logging).

Re: 1 gid *mostly* equals 80Wh

Posted: Sun Aug 12, 2012 2:41 pm
by vegastar
The rate of degradation does seem to be slowing down, as from October to now we have more time than when Tick Tock's car was bought to last October, and less degradation.

Re: 1 gid *mostly* equals 80Wh

Posted: Sun Aug 12, 2012 3:07 pm
by TickTock
edatoakrun wrote: And I still don't understand your method of calculating final gid value , TickTock.
Final gid count is recorded from the canbus at the end of the charge (not calculated - at least not by me).

Re: 1 gid *mostly* equals 80Wh

Posted: Mon Aug 13, 2012 7:10 am
by edatoakrun
I asked:

What degradation?

Doesn't this mean you believe that your battery may be accepting nearly the same kWh from the wall now, at both 80% and 100%, as it was when you began tracking it, on 10/01/2011?
TickTock wrote:
...Vegastar summed it up pretty well. It looks like I am down 6-8% from when I started tracking last October but I was already down 10-12% by then (why I bought a gid-o-meter and started logging).
When you say, “down 6-8%”, I assume you are referring to the three charge sessions that you posted on P.1 of this thread?

I have been looking at your reports, in their entity.

https://docs.google.com/spreadsheet/ccc ... li=1#gid=1" onclick="window.open(this.href);return false;

Maybe I am reading your entries incorrectly. Do columns P and Q. “0 to 80 wall”, and “0 to 100 wall” not represent your kWh use from the wall, for 80% and 100% charges respectively? For example, the earliest entries in these columns for October 2011 are 16.41 and 20.15, and your most recent are 16.90 and 21.20 respectively. Column Q has no entry for the 11/21/11 charge session you report on P.1.

Are P and Q reported from a meter, or calculated by other means?

As I interpreted the data in those columns, as plotted on your “LEAF Battery Capacity” chart, I thought I was seeing an account of relatively stable capacity, with no clear indication of capacity reduction over the 10/1/11 to 8/11/12 time period.

I understand charging efficiency “from the wall” will vary, but I would not think it would distort the trend line so significantly, in this sample.

What am I getting wrong?



As to prior to October 2011, do you now believe you had 10-12% greater (new LEAF “normal”) capacity on delivery, and lost that entire amount by October?

IIRC, at one point you suspected that you'd had reduced capacity in your LEAF, from the time of delivery.

Re: 1 gid *mostly* equals 80Wh

Posted: Mon Aug 13, 2012 7:34 am
by TomT
No longer having a Gid Meter, I decided I wanted to get an idea of where I was... Thus, last night, in the interest of science, I ran it down to turtle and charged to 100%
It took 21.1 Kwh which means I am down about 15% from what it was when new...