Today I was able to determine my 2019 40 kWh Leaf's battery resistance and compare it to my 2013 Leaf.
2019 40 kWh Leaf Battery Resistance Determination Using LeafSpy
I. Procedure - Very Generic for any BEV
a. Locate a very low density traffic street with about an 1/8 of a mile straight-away
b. With the vehicle turned on and in P mode, scroll to the LeafSpy screen to measure battery voltage (volts),
battery current (amps), battery temperature, and SOC (all on one screen).
c. Make sure there’s no traffic, place the vehicle in D mode (ECO on) and fully depress the accelerator
pedal (a basic “launch mode”) and hold for a few seconds until both the battery & current values
stabilize (about 3 seconds) and then record the battery voltage and current.
2. Calculation of battery resistance
V1 - battery voltage determined in “b”.
V2 - battery voltage determined in “c”
I - battery current determined in “c”
Battery Resistance = (V1 - V2) / I
3. Actual in-car tests, (temp - 85F, SOC - 57%)
a. V1 - 355, V2 - 340, I - 365
R = (355 - 340) / 365 = .041 ohms
b. V1 - 355, V2 - 336, I = 366
R = (355 - 336) / 366, I = .052 ohms
R (average) = .047 ohms
4. 2019 40 kWh versus 2013 24 kWh battery resistance
Ratio of 2019 / 2013 = .047 / .060 = 80%
Theoretically the ratio of resistances based on battery sizes (24 / 40) should be 60%,
which indicates that the 2019 battery resistance should be about .036 ohms. This indicates
that the 2019 battery will typically be hotter when charging or driving than it would be had
the battery resistance scaled as expected - given the higher capacity - more cells/pouches in parallel.
Hopefully, someone with a Leaf Plus and a another with a 30 kWh Leaf will do the above very simple/fast test,
so comparative data for all Leaf models are available.
Upper left of LeafSpy screen displays battery voltage & current. Battery temp & SOC are also displayed on that screen.
6/6/19
Tests were done on the 2013 Leaf using both the LeafSpy method and the automatic method included in LeaF DD.
Both methods correlated.