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Gradual Capacity Loss (GCL)

Posted: Tue Nov 19, 2019 9:59 am
by nlspace
In the FSM there is discussion about the capacity gauge on the dash and the meaning of bars and how they change. This thread is to collect and investigate the available information about the gradual capacity loss signal.

Both the charge level and a capacity level of the pack are transmitted over the CAN buss to the combination meter
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The capacity level can change based upon gradual capacity loss

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And the charge level can apparently change based upon temperature
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GCL signal on the CAN buss

Posted: Tue Nov 19, 2019 10:01 am
by nlspace
The Lithium Battery Controller (LBC) has a fault code related to Gradual Capacity Loss.

This is DTC P33D4

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Lithium Battery Controller (LBC)

Posted: Tue Nov 19, 2019 10:36 am
by nlspace
The LBC sends data items related to the battery pack to the Vehicle Control Module (VCM) over the CAN buss, including this GCL signal.

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Gauge segments information

Posted: Tue Nov 19, 2019 1:09 pm
by nlspace
Some additional information about reading the gauges

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The temperature gauge also uses the GCL signal:

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The power and regen power levels for the power bubbles:

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Re: Gauge segments information

Posted: Tue Nov 19, 2019 2:06 pm
by Astros
nlspace wrote:
Tue Nov 19, 2019 1:09 pm
The temperature gauge also uses the GCL signal:

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Thanks for posting this! I was very interested to see the official mapping of battery temperature bars to temperature. It looks a lot like many of us have guessed, but I haven't seen anything official before. I assume this will be the same for later Leafs (this manual is for 2012, correct?), but I wonder if @DaveinOlyWA or others have any thoughts on this?

Re: GCL signal on the CAN buss

Posted: Tue Nov 19, 2019 2:47 pm
by cwerdna
nlspace wrote:
Tue Nov 19, 2019 10:01 am
The Lithium Battery Controller (LBC) has a fault code related to Gradual Capacity Loss.

This is DTC P33D4
I do wonder when that trips. I've seen pics of several vehicles that are 9 bar losers.

Re: Gradual Capacity Loss (GCL)

Posted: Sat May 16, 2020 6:06 am
by arnis
These are not like "somewhere in the middle" ranges.
I can confidently state that jump from 3 to 4 stars happen exactly when first sensor hits 5*C, and from 4 to 5 when first hits 15*C.
And from 5 to 6 also near 25*C.
So it appears that if temperature EXITS from the range, it switches to next one. But it holds on for as long as possible.
I've not observed in other direction. Likely these "ranges" are margins and arrows show "for how long it will stay in that bar state.
But there is some discrepancy below negative temps. Those bars change differently. So not sure what's happening there.