Accurate range estimates require two things:
1. an accurate estimate of the usable energy left in the battery.
2. an accurate estimate of your future driving conditions and habits.
Of course #2 uses your "recent" past history, which might be a good, or terrible, estimate. For the moment, let's assume it is a good estimate, with near identical past and future driving conditions.
The remaining usable energy estimate can be good, or poor, depending upon how it is done. It appears that the LEAF has enough information (the cell voltages, etc.) to make some reasonable ESTIMATES, but that it might not use all the available information to create (calculate) the SOC value (that it crudely displays), and probably uses in the Range calculation.
The lowest, weakest, least-charged cell-pair is what really determines when the car will stop. The pack voltage (sum of all the cell-pairs) can look good, like the battery has a good SOC, and the Pack Voktage could be used to calculate an "apparent" SOC estimate. However, one low cell-pair COULD stop the car long before this "apparent" SOC goes low.
Further, it was just reported in another thread (I cannot remember which one) information (apparently from the Service Manual) that indicated that the PACK voltage IS used to derive the "SOC", not the "lowest cell-pair" information.
Then, this "apparent" SOC could be still relatively high, but the car's "protect-the-lowest-cell" monitoring MIGHT shut down the driving much earlier than expected.
IF TRUE, this could explain the several cases of "unexpected exhaustion", and the lack of the "Low Battery" warnings (assuming that they are indeed, as reported, based on this "apparent" SOC).
Last edited by garygid
on Sun Mar 06, 2011 9:55 am, edited 1 time in total.
See SOC/GID-Meter and CAN-Do Info
2010 Prius, now for sale
2011 LEAF, sold in 2015
2018 Tesla Model 3
2014 Tesla S, Model 3 in 2019
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To Sell: X-treme 5000Li EV motorcycle