garygid wrote:I suggest that PERHAPS the GID/2 (0 to 140.5) is an estimate of the remaining USABLE pack voltage (about 394v full and 254v "exhausted").
I will have to do some graphing of some logs to see if that scaling and "meaning" works.
However, I believe that the TRUE low limit for the Pack really should be based upon the voltage of the lowest cell-pair, NOT on the Pack Voltage (to avoid damage to that lowest cell-pair).
Yes, the chief engineer did mention that they measure 96 voltages, and that the lowest / highest was part of the equation, as we know it has to be.
Much of this conversation, as previously posted, then centered around how many variables that they monitored to come up with DTE. To that end, Nissan IT folks were working on including elevation with the mapping and navigation equation. I think they are working toward the only possible solution that is possible to determine the most pertinent variables to calculate range.
Here is a crack at the complexity of challenges the Nissan algorithm programmers have to rise to.
Here are my notes on the Leaf SOC as presented, plaease excuse my lose interpetation of the information.
Seems more like a dark art than math based on quantifiable scientific information.
Waring read at your own risk of being even more confused when you get to the last part.
Basic process of Nissan on how they estimate SOC.
Load on the Lithium Battery pack Voltgae V & Current i
At start up can measure Open Circuit Voltage (OCV)
Graph OCV over driving distance along with varying current and voltage estimate using V and i convet to SOC
Difficult to estimate during charging/discharging. Cannot measure OCV with load. Estimate OCV from V and i during driving time line.
End of driving again difficult to estimate. Just after charging/discharging. cannot measure OCV with influence of chemical reaction in battery.
Adjustment of estimate SOC value is adjusted to match vehicle behavior "Mysterious moves" occures in some scene.
Full charging stops at MAX SOC 192 Cells.
Decend Cell of max tolerance. Estimate value (Si) cells Real Value
Decending Cell of average estimated value (2*) Correction of estimate tolerances cause by sensore, cell tolerance etc.
Decending Cell of minimum tolerance.
(1) Shift SOC by area e.g. drop at shift timing
Estimate e.g.(2*) this decends but then assends briefly then desends back down to empty.
Empty___________________________Judge empty at Min SOC.
Here I give extremly brief notes about the 12 segment SOC meter.
SOC sharp drop cannot be recognized between the 6th & 4th segments (example shows). Basically a series of calculated corrections are done so in summary to prevent an overestimate SOC.
Increase risk of empty. SOC becomes "0" (I believe its below the segment) with some energy.
This is to Reduce risk of empty.
Estimated Distance to Empty (DTE)
Energy consumption ratio could be more varible factor than SOC.
DTE would be better indicator - carefule drivers
DTE(km)=SOC(KWH) x Energy consumption rate (km/KWH)
Changed by Acceleration, Regen, Climae Ctrl, Gradient etc.
If it sounds confusing that's because it is, we do not have the complete picture.