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Big difference SOC vs GID

Posted: Thu Jan 23, 2020 2:28 pm
by Easter123
Hi there, I bought an inexpensive 2011 Leaf about 9 months ago, at the time with 9 capacity bars left. We use it for driving around town and love it; it went down to 8 capacity bars about six months ago.

Lately, the range has been doing some funky things...dropping WAY faster than the GOM would predict, dropping two range bars in quick succession, losing charge bars just by turning the car on, and on the rare occasions that we use a quick charge the charger will read 40+% full even when the dash reads a super low range, and only one or two range bars.

So I finally went ahead and set up Leafspy, and have been reading a lot about how to interpret. Forgive me if this is a stupid question--I'm no engineer--but I'm trying to understand why there is such a huge difference between the SOC% (which seems to correlate with what the dash reads) and GID% (which seems to coordinate more with actual range).For instance, here's how it looked after being fully charged and left for a few hours. https://ibb.co/0JSBvgc

That ~30% difference between SOC and GID seems approximately constant no matter how much of the charge is used. Any thoughts, anything to be done, is this the source of our woes?

Re: Big difference SOC vs GID

Posted: Thu Jan 23, 2020 2:43 pm
by Astros
Easter123 wrote:
Thu Jan 23, 2020 2:28 pm
So I finally went ahead and set up Leafspy, and have been reading a lot about how to interpret. Forgive me if this is a stupid question--I'm no engineer--but I'm trying to understand why there is such a huge difference between the SOC% (which seems to correlate with what the dash reads) and GID% (which seems to coordinate more with actual range).For instance, here's how it looked after being fully charged and left for a few hours. https://ibb.co/0JSBvgc
Could you also post a screenshot of the first LeafSpy screen? That's the one with a histogram of the cell voltages. My guess would be that you have at least one cell at a very different voltage than the rest.

Re: Big difference SOC vs GID

Posted: Thu Jan 23, 2020 2:45 pm
by Easter123
Thanks! This is how it looked after a full charge (and sitting for a few hours) https://ibb.co/DwmS5wP

This one is after a few miles of driving. https://ibb.co/NSZSDTs

Re: Big difference SOC vs GID

Posted: Thu Jan 23, 2020 2:50 pm
by kebin
From what I understand:
  • GID% is the percentage of energy available relative to the battery capacity when it was new (so if your battery SOH is 65%, GID% can never be higher than this)
  • SOC% is the percentage of energy available relative to the current (degraded) battery capacity

Re: Big difference SOC vs GID

Posted: Thu Jan 23, 2020 8:54 pm
by nlspace
You need to replace your 12V battery. It is weak, old or worn out (sulfated) due to insufficient charging by the DC converter. An external lead acid charger should be used periodically to charge at 14.4 in order to de-sulfate the plates and extend the service life of the aux battery.

Re: Big difference SOC vs GID

Posted: Thu Jan 23, 2020 9:39 pm
by Astros
Easter123 wrote:
Thu Jan 23, 2020 2:45 pm
Thanks! This is how it looked after a full charge (and sitting for a few hours) https://ibb.co/DwmS5wP

This one is after a few miles of driving. https://ibb.co/NSZSDTs
These are perfectly fine cells, so nlspace is right that the 12V battery is the next most likely culprit. When that gets low, all sorts of systems start behaving strangely.

Re: Big difference SOC vs GID

Posted: Thu Jan 23, 2020 11:09 pm
by Virtuallydead
kebin wrote:
Thu Jan 23, 2020 2:50 pm
From what I understand:
  • GID% is the percentage of energy available relative to the battery capacity when it was new (so if your battery SOH is 65%, GID% can never be higher than this)

I believe that is correct. LeafSpy does not know your battery is degraded unless you tell it. Thus your fully charged GIDs right now (I'm gonna guesstimate 182) is being compared to the original 21.5kWhr LeafSpy thinks the battery has available.
Read the GIDs value at the next 5 times you charge to 100%. Find the average. Go to LeafSpy SETTINGS menu.In the BATTERY section change MAX GIDS to be your calculated value.
Now LeafSpy knows what the capacity of the battery is, and %GIDS will match your car's display.

Re: Big difference SOC vs GID

Posted: Fri Jan 24, 2020 5:25 am
by Virtuallydead
Virtuallydead wrote:
Thu Jan 23, 2020 11:09 pm
kebin wrote:
Thu Jan 23, 2020 2:50 pm
From what I understand:
  • GID% is the percentage of energy available relative to the battery capacity when it was new (so if your battery SOH is 65%, GID% can never be higher than this)
Now LeafSpy knows what the capacity of the battery is, and %GIDS will match your car's display.
Oooops. 2011 doesn't have the % remaining in the display does it?
At least now %GIDs and SOC will line up more accurately with reality in LeafSpy.

Re: Big difference SOC vs GID

Posted: Sat Jan 25, 2020 6:04 pm
by DaveinOlyWA
You have degradation. When new, the GID % will be higher than SOC. As degradation sets in, the numbers will eventually merge as the GIDs continue to drop.

GIDs is measure of the capacity of the pack. SOC is how full that pack is. Even if half degraded, you can still get SOC of 100% (or whatever) but GIDs will be no than around 50%

Re: Big difference SOC vs GID

Posted: Sun Jan 26, 2020 7:01 am
by jjeff
Virtuallydead wrote:
Fri Jan 24, 2020 5:25 am
Virtuallydead wrote:
Thu Jan 23, 2020 11:09 pm
kebin wrote:
Thu Jan 23, 2020 2:50 pm
From what I understand:
  • GID% is the percentage of energy available relative to the battery capacity when it was new (so if your battery SOH is 65%, GID% can never be higher than this)
Now LeafSpy knows what the capacity of the battery is, and %GIDS will match your car's display.
Oooops. 2011 doesn't have the % remaining in the display does it?
At least now %GIDs and SOC will line up more accurately with reality in LeafSpy.
Correct, the MY11 and MY12 models lacked this very handy display so some members like myself purchased an aftermarket(home built) Leaf DD among other devices to display SOC%(and many other things) and it's still working :)