What is a "Gid"?

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lenny said:
garygid said:
If the Gids are essentially 80 watt-hours each, why are the top 20 or so "always" used up so much quicker than those in the center of the range?
Less regeneration when the battery is full? Not enough details regarding your observation.

At least now I know what's a "gid" :)

(So I like graphs in case you hadn't noticed) I took a log last night of a 100% charge and another of my commute to work. During this drive I observed the gids being used up quicker at the beginning of the drive. However, upon plotting the data, it appears to be accurate. In this graph, I logged the V*I*delta_time into the battery and plotted the accumulated total both during the 100% charge and during the first part of my drive. Zoomed in to the top 80 gids for detail and there is no evidence of significant difference in the amount of charge associated with a gid during the start of the drive and later. During the charge it looks like just over 80wh per gid at the top 3kwh and during discharge it is just over 70wh. Indeed, it appears any faster drop in gids I may have observed was due to more energy consumption (lack of regen?) rather than "gid correction" as I previously suspected. Also interesting to note that there *does* seem to be a correction during the charge.
chvsdisgids.jpg
 
Looks like the top 13 GIDs during discharge drop quickly even though not much energy appears to be used.

At 14 kWh there is 184 discharging, but 204 when charging.

But, we really only care if the GIDs are a repeatable indicator of discharging "progress".

As the battery loses capacity, we do not know if the GIDs decrease.

Nissan seems to say that the Fuel-Bars will still "100% fill" to 12 Bars even if the Capacity is only 70%. Thus the Fuel-Bars will shrink in energy capacity (and range) as the battery ages. Yes, that makes the fuel bars even more useless.
 
garygid said:
As the battery loses capacity, we do not know if the GIDs decrease.
That would be a reasonable assumption, I believe. Didn't we see this effect with some drivers in Seattle during the recent snow storm? Battery capacity contracts in low ambient temps.
 
surfingslovak said:
garygid said:
As the battery loses capacity, we do not know if the GIDs decrease.
That would be a reasonable assumption, I believe. Didn't we see this effect with some drivers in Seattle during the recent snow storm? Battery capacity contracts in low ambient temps.

Yes, we have several runs like that:

"started trip 5:30 AM 97.8 SOC GID 274 temp 38º "

100.1 miles / 5.3 miles per kWh = 18.88kWh burned.

Based on this run with a Gidmeter at a cold battery temperature, it once again appears that the Gids are elastic, much like the battery level bars are. The Gids did not significantly read lower, even though there was an over 10% demonstrated loss of battery capacity due to cold weather.



Here's another data point, albeit without a Gidmeter:

100% charge (usable, not SOC) to Turtle

Assumed battery temperature at start: -13C (8.6F) up to -10C ambient (14F)
Final Dash Km/kWh: 7.0 (4.34 miles/kWh)
Km traveled total: 125.1 (77.56 miles)

Calculated Battery Capacity: 17.87 kWh - 85%
 
If GIDs decrease with age-related capacity loss, then
there must be a "Capacity" value that is used to:
1. create the Capacity Bars
2. scale the GIDs when creating the 12 Fuel-Bars
(which Nissan says do NOT diminish with diminished Capacity).
 
garygid said:
If GIDs decrease with age-related capacity loss, then
there must be a "Capacity" value that is used to:
1. create the Capacity Bars
2. scale the GIDs when creating the 12 Fuel-Bars
(which Nissan says do NOT diminish with diminished Capacity).
There is. There is an actual number generated called "HV Batt Gradual Capacity Loss Display" and even a "Gradual Capacity Loss Segments" that is sent to the CM (Combination Meter).

The "Gids" (Stored Watt-Hours) aren't being scaled, they are being calculated. Another number that is tracked is total current capacity in amp-hours, along with many other interesting parameters, such as the "Gradual Capacity Loss Coefficient".

-Phil
 
Ingineer said:
The "gids" will read lower as the battery ages, as the stored kWh will be lower.
Does this mean that the number of gids reading on a properly balanced and fully charged battery is a good proxy for battery capacity?
 
Stoaty said:
Ingineer said:
The "gids" will read lower as the battery ages, as the stored kWh will be lower.
Does this mean that the number of gids reading on a properly balanced and fully charged battery is a good proxy for battery capacity?
It's not a "proxy", as I've stated many times, a "Gid" is 80 watt-hours. It's actual stored capacity. Also, you will never get it "fully" charged, at least not without bypassing Nissan's systems.

-Phil
 
Ingineer said:
It's not a "proxy", as I've stated many times, a "Gid" is 80 watt-hours. It's actual stored capacity. Also, you will never get it "fully" charged, at least not without bypassing Nissan's systems.
By "fully" I mean charge to 100% on Nissan's scale (which is actually 94% SOC as you have pointed out).
 
Has anyone noticed a difference in the number of Gids after a full charge based on the ambient (and presumably battery) temperature? For example, do you see the same maximum value after charging the battery at 50 degrees in the winter versus after charging it at 70 degrees in the summer? My Gids after a full charge are a bit lower than I recall from the summer. I am wondering if this is due to the 20 degree drop in average temperature, or if I have permanently lost those Gids. :(
 
Stoaty said:
Has anyone noticed a difference in the number of Gids after a full charge based on the ambient (and presumably battery) temperature? For example, do you see the same maximum value after charging the battery at 50 degrees in the winter versus after charging it at 70 degrees in the summer? My Gids after a full charge are a bit lower than I recall from the summer. I am wondering if this is due to the 20 degree drop in average temperature, or if I have permanently lost those Gids. :(

I don't think temperature has anything to do with it. I got 282 twice a few days ago, in 10 F temperatures.

This was after starting a "top off" charge manually by pressing the timer override button. Before "topping off" the value was at 279. I have a 80% timer set.
 
Argh! I am also embarrassed by not knowing what a "GID" might be, so this thread's title was an immediate attention getter. I presume somewhere in its ten pages of postings there is an actual answer to the title question, but I can't seem to arrange the display to find it. I've got "sort by post date selected", but I find that the first item on "page 1 of 10" has a post time within a week of the last item on "page 10 of 10". Phooey; and I thought these BBC-powered fora were more standardized..
 
It is data from the car that is presented in about 281 units, that indicate the energy in the battery. 281 is a full battery, zero is empty. Each unit has approximately 70 to 80 watt/hours of energy. Unfortunately, the value is not a fixed amount, as batteries with various temperatures (and thus various energy) may have the same Gid number.

As the battery loses capacity, either through capacity loss of the battery through cycles or time, or from energy expended, will reduce the Gid count.

It's named after "garygid", whose product can display this number for the operator.


Levenkay said:
Argh! I am also embarrassed by not knowing what a "GID" might be, so this thread's title was an immediate attention getter. I presume somewhere in its ten pages of postings there is an actual answer to the title question, but I can't seem to arrange the display to find it. I've got "sort by post date selected", but I find that the first item on "page 1 of 10" has a post time within a week of the last item on "page 10 of 10". Phooey; and I thought these BBC-powered fora were more standardized..
 
Levenkay said:
Argh! I am also embarrassed by not knowing what a "GID" might be, so this thread's title was an immediate attention getter. I presume somewhere in its ten pages of postings there is an actual answer to the title question, but I can't seem to arrange the display to find it. I've got "sort by post date selected", but I find that the first item on "page 1 of 10" has a post time within a week of the last item on "page 10 of 10". Phooey; and I thought these BBC-powered fora were more standardized..

Gids was first suggested by member 91040 in this post

http://www.mynissanleaf.com/viewtopic.php?f=44&t=5582&start=10#p129689" onclick="window.open(this.href);return false;

Gids represent the State of Charge (SOC) of the battery pack and gets it's name from member garygid from his development contributions to a meter to log and analyze the CAN bus on the LEAF to find the SOC messages.
 
Nekota said:
Gids was first suggested by member 91040 in this post

http://www.mynissanleaf.com/viewtopic.php?f=44&t=5582&start=10#p129689" onclick="window.open(this.href);return false;

Gids represent the State of Charge (SOC) of the battery pack and gets it's name from member garygid from his development contributions to a meter to log and analyze the CAN bus on the LEAF to find the SOC messages.
Thank's for the answer! I wonder if Gary expected hi's fame?
 
I have just gotten the obd2 module and the Leafspy Pro app. I have read all of the responses on this thread, but still have not gotten the significance of the "GID". I understand that at full charge, a GID value of 281 is the highest possible, but I still would like to know the value of this information as time goes on. Is there a table of "perfect" values over time that shows that the battery is in good nick? I am not an electrical engineer so I think a lot of us would like to know how we can interpret the GIDS in our own cars?
 
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