User avatar
evnow
Moderator
Posts: 11480
Joined: Thu Apr 22, 2010 11:41 am
Delivery Date: 25 Feb 2011
Leaf Number: 303
Location: Seattle, WA

Re: What is a "Gid"?

Thu Feb 09, 2012 8:46 am

The unpredictability of gids w.r.t. usage is one reason I've almost stopped using my SOC meter - I no longer log it after every trip.

Question to battery experts is - is there a different method by which to estimate the SOC better ? Perhaps we will see this in Leaf from next year ? How do other EVs measure SOC ?
1st Leaf : 2/28/2011 to 5/6/2013
2nd Leaf : 5/4/2013 to 3/21/2017
Volt : 3/25/2017 to 5/25/2018
Model 3 : 5/10/2018 to ?

User avatar
TickTock
Posts: 1701
Joined: Sat Jun 04, 2011 10:30 pm
Delivery Date: 31 May 2011
Leaf Number: 3626
Location: Queen Creek, Arizona
Contact: Website

Re: What is a "Gid"?

Thu Feb 09, 2012 8:50 am

Herm wrote:
lukati wrote: For me the important information coming from Phil's data is the fact that the BMS protects only 2% capacity at the bottom and ~5% at the top. Unlike the Prius NiMH battery that Toyota won't let you abuse, your use pattern on the LEAF will truly affect the longevity of the pack. We knew that going in, now we have the numbers to prove it.
Nissan seems to be confident on the durability of the batteries.. hopefully they dont pull a Honda and reprogram the limits after 3 years to reduce battery degradation.

It appears we finally have our fine grained battery wear meter..
Yup, and it appears my battery arrived from the dealer already 15% degraded. About a month after getting the car I purchased one of Gary's boxes because I suspected something was wrong (was not getting the range others were reporting) and found I was only reading 239 after a 100% charge despite still having 12 bars on the capacity meter. Phil's confirmation of the gid or watt-hours unit being a standard across all cars (80wh) proves it. Going to be fun trying to tell that to the dealer... Interestingly, as I used the car, my capacity seemed to creep up (despite ouside temperatures going south). I have, in the last month, been getting as high as 256 on a 100% charge.

User avatar
TomT
Posts: 10642
Joined: Sun Aug 08, 2010 12:09 pm
Delivery Date: 01 Mar 2011
Leaf Number: 000360
Location: California, now Georgia
Contact: Website

Re: What is a "Gid"?

Thu Feb 09, 2012 9:01 am

Now that we appear to have some idea of how many Kwh expended (approximately 75) each Gid represents, it might be nice to add that as a third Gid Meter display option (Gids, percent, and Kwh). This would be handy for estimating your available range since you would simply need to mentally multiply that number by your displayed M/Kwh to get your remaining range in miles... Yes, I know that neither the amount of energy per Gid nor a typical drive's M/Kwh is constant, but it would still provide some guidance and be handy...
garygid wrote:Yes, some folks started calling the "unknown-units" value (0 to 281) a "Gid" after my "garygid" forum handle. Then, the "soc" Meter might be a Gid-Meter.
Last edited by TomT on Thu Feb 09, 2012 2:12 pm, edited 2 times in total.
Leaf SL 2011 to 2016, Volt Premier 2016 to 2019, and now:
2019 Model 3; LR, RWD, FSD, 19" Sport Wheels, silver/black; built 3/17/19, delivered 3/29/19.

User avatar
linkim
Posts: 495
Joined: Thu Dec 16, 2010 5:06 pm
Location: Silicon Valley

Re: What is a "Gid"?

Thu Feb 09, 2012 9:04 am

TomT wrote:This would be handy for estimating your available range since you would simply need to mentally divide that number by your displayed M/Kwh to get your remaining range in miles...
Instead of dividing, you should multiply (kWh X miles/kWh = miles).
LEAF SL + QC
Reserved: 4/20/10
Received: April 19, 1 year after reservation

User avatar
abasile
Posts: 1922
Joined: Thu Sep 02, 2010 10:49 am
Delivery Date: 20 Apr 2011
Location: Arrowbear Lake, CA

Re: What is a "Gid"?

Thu Feb 09, 2012 9:08 am

TickTock wrote:it appears my battery arrived from the dealer already 15% degraded
I wonder if it came from the factory this way, which would seem highly unusual, or if there was some other factor at play. Admittedly this is a bit off-topic, but I do fear that perhaps some inept dealers have left their LEAFs sitting at 100% charge for weeks or months, which would actually be a violation of the car's warranty due to the battery degradation it would cause. I'd only be concerned about demo cars, as well as "orphans" sitting on the lot for extended periods due to the dealer being unwilling to budge on price. Before purchasing such a LEAF, it would be ideal to have a way of checking the battery. I wonder if obtaining the number of gids after charging to 100% and allowing four extra hours for balancing would be good enough.
2011 LEAF at 71K miles, pre-owned 2012 Tesla S 85 at 98K miles
LEAF battery: 9/12 bars and < 49 Ah (-28% vs. new)
Tesla battery: 250+ miles of range (-5% vs. new)

User avatar
TomT
Posts: 10642
Joined: Sun Aug 08, 2010 12:09 pm
Delivery Date: 01 Mar 2011
Leaf Number: 000360
Location: California, now Georgia
Contact: Website

Re: What is a "Gid"?

Thu Feb 09, 2012 9:13 am

Yep, I realized what I was thinking is not what I typed and corrected it. Thanks!
linkim wrote:
TomT wrote:This would be handy for estimating your available range since you would simply need to mentally divide that number by your displayed M/Kwh to get your remaining range in miles...
Instead of dividing, you should multiply (kWh X miles/kWh = miles).
Leaf SL 2011 to 2016, Volt Premier 2016 to 2019, and now:
2019 Model 3; LR, RWD, FSD, 19" Sport Wheels, silver/black; built 3/17/19, delivered 3/29/19.

User avatar
TonyWilliams
Posts: 10091
Joined: Sat Feb 19, 2011 1:48 am
Location: San Diego
Contact: Website

Re: What is a "Gid"?

Thu Feb 09, 2012 10:04 am

Ingineer wrote:
Either way, I can assure you what you are calling SOC, Nissan is calling stored watt-hours.

-Phil
It's only been referred to SOC in the relationship of what is available to the vehicle operator. To be honest, I don't want data displayed that doesn't reflect available energy. So far, the Gid count seems to be the best SOC that we have for this purpose.

User avatar
TonyWilliams
Posts: 10091
Joined: Sat Feb 19, 2011 1:48 am
Location: San Diego
Contact: Website

Re: What is a "Gid"?

Thu Feb 09, 2012 10:11 am

TomT wrote:... simply need to mentally multiply that number by your displayed M/Kwh to get your remaining range in miles... .
It's not going to work well with the current data. It doesn't add up.

I've said this several times now, but I don't want people seeing 281 Gids, then multiplying by 80, getting 22.5kWh, then multiplying by the dash or console miles/kWh (let's say 4.8), and thinking they'll drive 108 miles. With a 70F battery, we already know that distance will be closer to 100.

That is why the previous discussions were centered around 70 and 75 watt hours per Gid. That data more accurately reflects distance traveled from Gid count.

There is a significant difference in this 80 value per Gid, and what we can actually use. We do not have Gid data at exceptionally low temps to see if it does adjust for temp. I believe it will do so for degradation.

User avatar
TomT
Posts: 10642
Joined: Sun Aug 08, 2010 12:09 pm
Delivery Date: 01 Mar 2011
Leaf Number: 000360
Location: California, now Georgia
Contact: Website

Re: What is a "Gid"?

Thu Feb 09, 2012 10:23 am

Based on my experience, 75 would seem to be about right and tracks very closely with my actual numbers over the last 12 months and 14,000 miles... YMMV.
TonyWilliams wrote:
TomT wrote:... simply need to mentally multiply that number by your displayed M/Kwh to get your remaining range in miles... .
It's not going to work well with the current data. It doesn't add up.
I've said this several times now, but I don't want people seeing 281 Gids, then multiplying by 80, getting 22.5kWh, then multiplying by the dash or console miles/kWh (let's say 4.8), and thinking they'll drive 108 miles. With a 70F battery, we already know that distance will be closer to 100.
That is why the previous discussions were centered around 70 and 75 watt hours per Gid. That data more accurately reflects distance traveled from Gid count.
There is a significant difference in this 80 value per Gid, and what we can actually use. We do not have Gid data at exceptionally low temps to see if it does adjust for temp. I believe it will do so for degradation.
Leaf SL 2011 to 2016, Volt Premier 2016 to 2019, and now:
2019 Model 3; LR, RWD, FSD, 19" Sport Wheels, silver/black; built 3/17/19, delivered 3/29/19.

User avatar
TickTock
Posts: 1701
Joined: Sat Jun 04, 2011 10:30 pm
Delivery Date: 31 May 2011
Leaf Number: 3626
Location: Queen Creek, Arizona
Contact: Website

Re: What is a "Gid"?

Thu Feb 09, 2012 10:58 am

Since gids are a unit of energy and the battery has losses, gids out will always be less than gids in. Total round trip efficiency is 85% and half of this comes close to 75/80 so the numbers start to make sense if you account for losses. The 281 everyone (else) sees after a 100% charge is probably "gids in." Not to be confused with "gids out." Add this on top of the integrating error, hall effect sensor drift, etc, and we can see why the ECU needs to adjust the value time to time.

Return to “Engineering”