Feature Request: Calculate SOH by consumption with battery loss

[CONSULitAS]

Based on the idea of George Metze: https://groups.google.com/g/csv-alpha/c/3ghuvDNQySo/m/Gk52T-WZAgAJ

But with a different and more precise algorithm for calculating SOH.

The main idea is that the shown (and via API readable) SOC values are not accurate enough to get a reasonable accuracy for a SOH calculation, because 2x 0.5% SOC is a rather high error. If you measure only a small step in SOC (e.g. 80% -> 66 %) the error multiplies and you get an overall error up to +/- 10% SOH. This is not reasonable.

To solve this, you have to measure a high step in SOC and find a way to get a more accurate value for the current SOC at start and end. If you wait for the SOC value to flip, you can be rather sure, that the Value is accurate just now (e.g. 92,00% but reading 92%), even if the shown/readable value has less accuracy.

In a nutshell:

• measure energy consumption while driving for x % SOC
• try to max x for accuracy
• multiply consumption in kWh with 100 % divided by x % to get capacity in kWh
• divide capacity in kWh by 100% SOH capacity (e.g. 75 kWh) to get SOH in %

Step by step (simple state machine)

• state = "idle"
• if state is "idle" and SOC is lower than 75 %
  • state = "start SOC to low"
  • wait for SOC higher or equal to 91 %
  • state = "waiting for SOC change"
• if state is "idle" and SOC is higher than 96 %
  • state = "start SOC to high"
  • wait for SOC to drop to less than 96% (value seems to be a bit inaccurate on higher SOC)
  • state = "waiting for SOC change"
• if state = "waiting for SOC change"
  • wait for any change of SOC to a lower value (e.g. from 91 % to 90 %)
  • store current SOC value in % (startSOC) and trip consumption in kWh (startkWh) for later use
  • state = "counting SOC and energy"
• if state = "counting SOC and energy"
  • wait until SOC drops to at least "startSOC-60 %" (e.g. 90 % - 60 % -> from 21 % to 20%)
  • state = "calculating"
  • calculate SOC difference (startSOC-currentSOC), energy difference (startkWh-currentkWh), capacity and SOH
• if state = "calculating"
  • wait until SOC drops to next lower step
  • calculate new values
• if trip ends
  • if state = "calculating"
  • store results with timestamp for GUI
  • else
  • delete stored values
  • state = "idle"
  • start over at first step

BTW: This algorithm gives reasonable results if you calculate by hand with the trip consumption value from CSV. But it is not very handy and accurate to write down the values while driving and to sit and wait for the SOC change in the driver display.

[Ixam97]

Interesting concept. I will put it on my bucket list for features that I maybe want to add in the future. For now I am focusing on refining core features and UI for potential public releases.

[CONSULitAS]

Update:

Push message, when SOH drops would be nice, too.

[CONSULitAS]

https://polestar.fans/t/soh-84-nach-25500-km/19881?u=consulitas