[Ovmsdev] Advice - mapping I3 data to the standard metrics

Thu Dec 17 20:40:26 HKT 2020

Hi Michael et al,

I set my first goal to get all the metrics that are required for the
standard dashboard to work on the I3. I've got some questions about the
intended use of the metrics. Hope someone can give advice:

I'm sorry this is a tome, I did work to shorten it.

1) How do I understand a "trip"?

My car has a trip-meter that you can reset.  It also by itself seems to
have some heuristic for trips that it uses for the "ecodrive" stuff.  There
are some PIDS that return trip-related data but I must still figure out
when they reset - whether it goes by the trip feature. But what does OVMS
regard as a "trip"?

For me: I would want it to work automatically - ie reset the trip stats
each time the car goes to READY except perhaps if it has just been a few
minutes since it was turned off.

2) About temperatures:  The i3 has SO MANY temperature sensors, especially
in the "electrical machine electronics" - how to map them to the standard
metrics in OVMS?

I guess you will say it's my call, but I'd like what I do to be consistent
with other vehicles.

There are the following standard metrics relating to temperature (you can
see some I mapped already)

a) Battery temps: These I took from a PID that returns a "coldest",
"hottest" and mean for the pack as a whole :

v.b.p.temp.avg                           21.27°C
v.b.p.temp.max                           21.83°C
v.b.p.temp.min                           21.04°C
v.b.p.temp.stddev
v.b.p.temp.stddev.max

v.b.temp                                 21.27°C

A min, max, and mean doesn't give me enough to work out a standard
deviation. And: what is a "maximum" stddev?  Is that over time?

And for v.b.temp I just used the avg temp from above.  I could have used
the max instead - any view? :

b) v.e.temp: ("environmental temp") Found a value for outside / ambient
temp :

v.e.temp                                 21.5°C

c) v.m.temp - motor temp: There are two temps for the "e-machine".  These
are inside the actual electric motor.  I used the hotter of the two :

v.m.temp                                 25.3968°C

d) v.e.cabintemp:  I haven't looked into the aircon system yet:

e) v.i.temp: Inverter temp:

There are 4 inverter temps:

       // Temperature converter phase U / Temperatur Umrichter Phase U
 2020-12-16 17:59:10 SAST D (289275) v-bmwi3: From ECU EME, pid AE_TEMP_LE:
got STAT_TEMP_UMRICHTER_PHASE_U_WERT=35.8020"°C"
        // Temperature converter phase V / Temperatur Umrichter Phase V
2020-12-16 17:59:10 SAST D (289275) v-bmwi3: From ECU EME, pid AE_TEMP_LE:
got STAT_TEMP_UMRICHTER_PHASE_V_WERT=35.0532"°C"
        // Temperature converter phase W / Temperatur Umrichter Phase W
2020-12-16 17:59:10 SAST D (289275) v-bmwi3: From ECU EME, pid AE_TEMP_LE:
got STAT_TEMP_UMRICHTER_PHASE_W_WERT=34.7568"°C"
        // Temperature inverter gate driver / Temperatur Inverter Gatedriver
2020-12-16 17:59:10 SAST D (289275) v-bmwi3: From ECU EME, pid AE_TEMP_LE:
got STAT_TEMP_UMRICHTER_GT_WERT=45.5832"°C"

I just took the highest.

f) v.c.temp: charger temp:

For v.c.temp there are also 4 measurements:

        // Temperature SLE-PowerFactorCorrection / Temperatur
SLE-PowerFactorCorrection
2020-12-16 17:59:10 SAST D (289285) v-bmwi3: From ECU EME, pid AE_TEMP_LE:
got STAT_TEMP_SLE_PFC_WERT=27.0972"°C"
        // Temperature SLE rectifier / Temperatur SLE-Gleichrichter
2020-12-16 17:59:10 SAST D (289285) v-bmwi3: From ECU EME, pid AE_TEMP_LE:
got STAT_TEMP_SLE_GR_WERT=28.0488"°C"
        // Temperature SLE push-pull converter / Temperatur
SLE-Gegentaktwandler
2020-12-16 17:59:10 SAST D (289285) v-bmwi3: From ECU EME, pid AE_TEMP_LE:
got STAT_TEMP_SLE_GTW_WERT=27.5652"°C"
        // Temperature of the SLE board / Temperatur des SLE Boards
2020-12-16 17:59:10 SAST D (289285) v-bmwi3: From ECU EME, pid AE_TEMP_LE:
got STAT_TEMP_SLE_BO_WERT=29.0004"°C"

(SLE also called KLE elsewhere - Komfort Ladeelectronik I think it is)

I took the hottest.

My car also has DC charging but if I understand that rightly there isn't
any high power electrical stuff onboard for that, contactors are closed to
give the external - so nothing to get hot except the battery itself.

Then I have some more temps -

DC/DC converter used to supply the 12v systems (and to charge the 12
battery).

I don't see any standard metrics for this subsystem?

        // Temperature of the DCDC board / Temperatur des DCDC Boards
    2020-12-16 17:59:10 SAST D (289285) v-bmwi3: From ECU EME, pid
AE_TEMP_LE: got STAT_TEMP_DCDC_BO_WERT=35.8488"°C"
        // Temperature DC / DC push-pull converter / Temperatur
DC/DC-Gegentaktwandler
2020-12-16 17:59:10 SAST D (289285) v-bmwi3: From ECU EME, pid AE_TEMP_LE:
got STAT_TEMP_DCDC_GTW_WERT=32.0892"°C"
        // Temperature DC / DC buck converter / Temperatur DC/DC-Tiefsetzer
2020-12-16 17:59:10 SAST D (289285) v-bmwi3: From ECU EME, pid AE_TEMP_LE:
got STAT_TEMP_DCDC_TS_WERT=59.9976"°C"
        // Temperature of the DCDC board / Temperatur des DCDC Boards
2020-12-16 17:59:10 SAST D (289285) v-bmwi3: From ECU EME, pid AE_TEMP_LE:
got STAT_TEMP_DCDC_GR_WERT=31.6524"°C"

- "ELUP power output stage".  Dunno what "ELUP" is and didn't find it in
the technical training info I have.

        // Temperature on the power board - measuring point ELUP power
output stage / Temperatur auf dem Powerbord -
        // Messstelle ELUP Leistungsendstufe
2020-12-16 17:59:10 SAST D (289285) v-bmwi3: From ECU EME, pid AE_TEMP_LE:
got STAT_TEMP_ELUP_LE_WERT=30.0768"°C"

- And 2 processor temps:

        // Temperature processor MC0 / Temperatur Prozessor MC0
2020-12-16 17:59:10 SAST D (289285) v-bmwi3: From ECU EME, pid AE_TEMP_LE:
got STAT_TEMP_PROZESSOR_MC0_WERT=39.9048"°C"
        // Temperature processor MC2 / Temperatur Prozessor MC2
2020-12-16 17:59:10 SAST D (289285) v-bmwi3: From ECU EME, pid AE_TEMP_LE:
got STAT_TEMP_PROZESSOR_MC2_WERT=39.9048"°C"

3) What to do about "range".

So I found a pid that returns a "range" - but it always be the range in
so-called "Comfort" mode.  The car instrument display actually shows range
according to the mode the car is in.    I normally drive in "Eco-pro".

There's another PID that gives a figure for each of the 4 modes my car has
got.

How do other vehicles handle this?

I'd like to show users all the ranges, and then put the range in the
current mode into the standard metric v.b.range.est

And I don't think I understand exactly the difference between "est",
"ideal", and "full".

My best guess for how to make them work:

"est" is the figure the car gives up - either that "comfort mode" number or
the number for the current mode
"ideal": my best idea for how to get this is the WLTP range for the car's
battery capacity scaled by the SOH% and the SOC% to come up with some sort
of theoretically "possible" figure?
"full": not sure - My idea would be to take the "est" figure from the car
and scale it up to a range if the battery was full.

Thanks,
Steve
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