Unfortunately we lack much calibration of Hx to know whether it is really measuring the resistance by a similar method as LeafDD or whether it is some other factor that represents a loss of capacity that hasn’t been subject to calculation errors like we see for Ah/SoH.
Why do you insist on making H/Hx more difficult than it really is? Both LeafSpy and LeafDD both read the same data (0xXX) from the BMS
and present it without any modifications/calculations. If you think the H/Hx represents something other than what has been noted,
then please compile data which would indicate otherwise. If you haven't, buy LeafSpy Pro and start analyzing your own data.
You do realize that battery resistance is a key variable with regard to degradation for ANY battery, right? So it's very likely that Nissan
wanted that parameter determined by the BMS over time AND presented as another measure of the relative state of the battery's
health/degradation. Obviously as is case for SOH (a relative present Ahrs to the new Ahrs), having a parameter, e.g. H/Hx, would
be useful, right?
dwl wrote:The H measurement is mentioned separately in the LeafDD documentation. I read those notes as saying mohms is a calculation by LeafDD while H is extracted from the BMS. Sorry I don’t have LeafDD.
Correct. A battery resistance determination is done by using the method; R (battery) = delta V ( a change in battery voltage) divided
by delta I (a change in battery current). Every time hard acceleration is done, LeafDD calculates the battery resistance (SIMPLE).
The same approach can be used with LeafSpy. That shouldn't be too difficult to understand, right?
dwl wrote:Your data is very interesting. Your mohms data bounces around a large amount, as may be expected for the type of analysis being done, while Hx is much more heavily weighted and smoothed.
That's not true! My time series battery resistance data doesn't "bounce around a large amount". You do realize that the battery resistance
has two independent variables, i.e. time and temperature, SOC has basically no effect, right?
11/20/14 -13,700 miles, 76 mohms per LeafDD, 20 Deg, 73% SOC
11/27 -13,800 miles, 67 mohms per LeafDD, 25 deg, 63% SOC
11/30 - 13,900 miles, 56 mohms per LeafDD, 27 deg, 71% SOC
12/2 - 14.100 miles, 55 mohms per LeafDD, 28 deg, 67% SOC
12/16 - 14,500 miles, 89 mohms per LeafDD, 15 deg, 93% SOC
12/27/14 - 14,800 miles, 103 mohms per LeafDD, 11 deg, 24% SOC
3/10 - 17,400 miles, 60 mohms per LeafDD, 30 deg, 73% SOC
3/14 - 17, 550 miles, 56 mohms per LeafDD, 32 deg, 47% SOC
4/14 - 19,100 miles, 59 mohms per LeafDD, 25 deg. 38% SOC
5/4 - 19,989 miles, 64 mohms per LeafDD, 24 deg. 48% SOC
5/15 - 20,400 miles, 73 mohms per LeafDD, 20 deg. 41% SOC
5/22 - 20,700 miles, 58 mohms per LeafDD, 28 deg. 50% SOC
12/10/15 - 28,000 miles, 90 mohms per LeafDD, 19 deg. 92% SOC
4/5 - 32,000 miles, 74 mohms per LeafDD, 24 deg, 55% SOC
5/16 - 33,700 miles,89 mohms per LeafDD, 22 deg, 47% SOC
5/16 - 33.700 miles, 58 mohms per LeafDD, 31 deg, 76% SOC
10/5 - 39,300 miles, 100 mohms per LeafDD, 22 deg, 50% SOC
10/6 - 39,400 miles, 61 mohms per LeafDD, 30 deg, 51% SOC
10/7 - 39,500 miles, 80 mohms per LeafDD, 25 deg, 56% SOC
10/15 - 40,000 miles, 71 mohms per LeafDD, 27 deg, 45% SOC
10/30 - 41,000 miles, 74 mohms per LeafDD, 23 deg, 66% SOC
12/26/16 - 43,000 miles, 110 mohms per LeafDD, 13 deg, 77% SOC
6/10/17 - 49,600 miles, 89 mohms per LeafDD, 19 deg, 70% SOC
4/2/18 - 62,000 miles, 110 mohms per LeafDD, 18 deg, 94% SOC
6/13/18 - 65,000 miles, 84 mohms per LeafDD, 26 deg, 52% SOC
Again, still waiting for your data gathering and analysis with regard to your interpretation of H/Hx. Have you bought the LeafSpy Pro app yet,
i.e. it's a great app? If you feel that additional data from LeafSpy would help you to analyze H/Hx, put a request to Jim (Turbo3). He's always
receptive to LeafSpy update ideas. The Telsa version of LeafSpy (TM-Spy) has a helpful mode for determining battery resistance.
#1 Leaf SL MY 9/13: 74K miles, 48 Ahrs, 5.2 miles/kWh (average), Hx=70, SOH=78, L2 - 100% > 1000, temp < 95F, (DOD) > 20 Ahrs
#2 Leaf SL MY 12/18: 4.5K miles, 115 Ahrs, 5.5 miles/kWh (average), Hx=98, SOH=99, DOD > 20%, temp < 105F