No not sure at all. Was just wondering about the multiplication with 108 as proposed, when the value of 4912 was first divided by 100...kermit68 wrote: ↑Sun Feb 21, 2021 4:49 pmI may have missed some posts but I can't recall that we should use 108 as divisor to calculate the voltage .... To my memory the only 108 related voltage calculation is to get cell voltage average from battery pack voltage (0x490f).
Are you sure about that ?
Canbus and PID for the IPace
Re: Canbus and PID for the IPace
EV400 HSE (MY2020; MAR 2020); 18" ❄
H264 ICM: S20C VCS: 19.2
BECS: BPAAEBCACBE Maps: 06.2020
H264 ICM: S20C VCS: 19.2
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 Posts: 395
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 Location: Norway
Re: Canbus and PID for the IPace
I drove the car to up to my mountain cabin, charged it to 100% and checked the regenerated power against the 'max charge' level when I went home. This way I could find the divisor for the current as the regen power never will exceed max charge level.kermit68 wrote: ↑Thu Feb 18, 2021 12:11 pmJust to add some noise .... Using 40 and calculating istant power as current times voltage I got a peak power of 300kw (during an overtake) which is in excess of the declared 295kw. Using 36 or 38 as divisor to calculate current would lead to even higher power values so I'm almost conviced we can't go lower than 40.Maxwell_400 wrote: ↑Thu Feb 18, 2021 9:43 am
We are getting closer, I was happy with 36 as charge efficiency should be in the range 95%98% and 1/36 = 1s/1hr x 100.
But 36 to 38 then and 38 is closer to 40 as I have used as a good value from energy loss measurements.
And guess what, a divisor of 40 fits perfectly.
IPace SE++, MY20, 18" summer & winter, no panoroof, towbar, spare wheel, 20C, TCU 19.2, BECS: BPAAEBCACBE
Re: Canbus and PID for the IPace
Very goodMaxwell_400 wrote: ↑Sun Feb 21, 2021 10:53 pm
I drove the car to up to my mountain cabin, charged it to 100% and checked the regenerated power against the 'max charge' level when I went home. This way I could find the divisor for the current as the regen power never will exceed max charge level.
And guess what, a divisor of 40 fits perfectly.
MY20 Yulong White SE, 20", air suspension, privacy glass, black pack and other fine stuffs

 Posts: 395
 Joined: Mon Oct 14, 2019 10:09 am
 Location: Norway
Re: Canbus and PID for the IPace
Yes and when I integrate (current x voltage) I get 20kWh/100km which is exactly the same as reported by the triplog in the display. SOC delta was 23%, this gives a battery capacity of 86kWh which is very close to 90 x SOH = 85.5kWh. (By a coincidence the distance driven is 100km).kermit68 wrote: ↑Mon Feb 22, 2021 9:31 amVery goodMaxwell_400 wrote: ↑Sun Feb 21, 2021 10:53 pm
I drove the car to up to my mountain cabin, charged it to 100% and checked the regenerated power against the 'max charge' level when I went home. This way I could find the divisor for the current as the regen power never will exceed max charge level.
And guess what, a divisor of 40 fits perfectly.
Then we have it, we can calculate a lot of interesting parameters, like battery capacity, internal resistance, range, charge loss, energy regenerated, etc.
Some options for calculating the energy used:
Integration (current x voltage) over time = 20.1 kWh/100km = Excact the same as triplog in the car
Integration current over time x average voltage = 20.6 kWh/100km
Integration current over time x nominal voltage (108x3.6) = 18.7kWh/100km
Average current x average voltage x time used = 20.6 kWh/100km
Average current x nominal voltage (108x3.6) x time used = 18.7kWh/100km
Battery pack is at 129mOhms which is very high at +10 degrees but I guess it is due to the high SOC.
IPace SE++, MY20, 18" summer & winter, no panoroof, towbar, spare wheel, 20C, TCU 19.2, BECS: BPAAEBCACBE
Re: Canbus and PID for the IPace
I'm studying Python so I hope to be able in a shortwhile to be able to do the same calculationsMaxwell_400 wrote: ↑Mon Feb 22, 2021 11:48 am
Yes and when I integrate (current x voltage) I get 20kWh/100km which is exactly the same as reported by the triplog in the display. SOC delta was 23%, this gives a battery capacity of 86kWh which is very close to 90 x SOH = 85.5kWh. (By a coincidence the distance driven is 100km).
Then we have it, we can calculate a lot of interesting parameters, like battery capacity, internal resistance, range, charge loss, energy regenerated, etc.
Some options for calculating the energy used:
Integration (current x voltage) over time = 20.1 kWh/100km = Excact the same as triplog in the car
Integration current over time x average voltage = 20.6 kWh/100km
Integration current over time x nominal voltage (108x3.6) = 18.7kWh/100km
Average current x average voltage x time used = 20.6 kWh/100km
Average current x nominal voltage (108x3.6) x time used = 18.7kWh/100km
Battery pack is at 129mOhms which is very high at +10 degrees but I guess it is due to the high SOC.
Which SOH are you using as reference ? min/max/avg ? I'm using for my energy calculation the min but I don't know if I'm too conservative.
MY20 Yulong White SE, 20", air suspension, privacy glass, black pack and other fine stuffs
Re: Canbus and PID for the IPace
Does anyone already looked at PID FD0A on BCCM. In my data in different context, the value is always "0FA0", but when plugged on a DC fast charger, the value seems to be close to the charger voltage*10. Do you have any data on your side for FD0A while you charge ?
Same question for FD50. It also changed right after the fast charge. The first 4 bytes of FD50 seems to be equal to DD00, which is the relative time for the car since built time, so this value is the timestamp of the last fast charge ? This value also changed when I unpluged the car with the timestamp of the unplug event.
Same question for FD50. It also changed right after the fast charge. The first 4 bytes of FD50 seems to be equal to DD00, which is the relative time for the car since built time, so this value is the timestamp of the last fast charge ? This value also changed when I unpluged the car with the timestamp of the unplug event.
Last edited by dernotte on Tue Feb 23, 2021 2:00 am, edited 3 times in total.
Re: Canbus and PID for the IPace
On BCCM, PID FD20 is a 5 byte numbers, but the first number changed when I did a DC fats charger. Could it be the number of fast charge since day 1 ?
After this fast charge session, FD20 is copied in FD21, FD21 > FD22, FD22>FD23, FD23>FD24. It seems historical data to keep in the car (last 5) but the other byte are not very meaningful.
PID FD1A is a 4 byte number, strictly moving up, only change when when I fill the battery to 100% or stop charging. Cumulative Watt send to the battery since day 1 ?
After this fast charge session, FD20 is copied in FD21, FD21 > FD22, FD22>FD23, FD23>FD24. It seems historical data to keep in the car (last 5) but the other byte are not very meaningful.
PID FD1A is a 4 byte number, strictly moving up, only change when when I fill the battery to 100% or stop charging. Cumulative Watt send to the battery since day 1 ?
Re: Canbus and PID for the IPace
dernotte wrote: ↑Tue Feb 23, 2021 1:42 amOn BCCM, PID FD20 is a 5 byte numbers, but the first number changed when I did a DC fats charger. Could it be the number of fast charge since day 1 ?
After this fast charge session, FD20 is copied in FD21, FD21 > FD22, FD22>FD23, FD23>FD24. It seems historical data to keep in the car (last 5) but the other byte are not very meaningful.
PID FD1A is a 4 byte number, strictly moving up, only change when when I fill the battery to 100% or stop charging. Cumulative Watt send to the battery since day 1 ?
EV400 HSE (MY2020; MAR 2020); 18" ❄
H264 ICM: S20C VCS: 19.2
BECS: BPAAEBCACBE Maps: 06.2020
H264 ICM: S20C VCS: 19.2
BECS: BPAAEBCACBE Maps: 06.2020
Re: Canbus and PID for the IPace
Interesting. Could the copied values be to the trip log registers?dernotte wrote: ↑Tue Feb 23, 2021 1:42 amOn BCCM, PID FD20 is a 5 byte numbers, but the first number changed when I did a DC fats charger. Could it be the number of fast charge since day 1 ?
After this fast charge session, FD20 is copied in FD21, FD21 > FD22, FD22>FD23, FD23>FD24. It seems historical data to keep in the car (last 5) but the other byte are not very meaningful.
PID FD1A is a 4 byte number, strictly moving up, only change when when I fill the battery to 100% or stop charging. Cumulative Watt send to the battery since day 1 ?
EV400 HSE (MY2020; MAR 2020); 18" ❄
H264 ICM: S20C VCS: 19.2
BECS: BPAAEBCACBE Maps: 06.2020
H264 ICM: S20C VCS: 19.2
BECS: BPAAEBCACBE Maps: 06.2020

 Posts: 395
 Joined: Mon Oct 14, 2019 10:09 am
 Location: Norway
Re: Canbus and PID for the IPace
I use SOH and SOC average.kermit68 wrote: ↑Mon Feb 22, 2021 11:56 amI'm studying Python so I hope to be able in a shortwhile to be able to do the same calculationsMaxwell_400 wrote: ↑Mon Feb 22, 2021 11:48 am
Yes and when I integrate (current x voltage) I get 20kWh/100km which is exactly the same as reported by the triplog in the display. SOC delta was 23%, this gives a battery capacity of 86kWh which is very close to 90 x SOH = 85.5kWh. (By a coincidence the distance driven is 100km).
Then we have it, we can calculate a lot of interesting parameters, like battery capacity, internal resistance, range, charge loss, energy regenerated, etc.
Some options for calculating the energy used:
Integration (current x voltage) over time = 20.1 kWh/100km = Excact the same as triplog in the car
Integration current over time x average voltage = 20.6 kWh/100km
Integration current over time x nominal voltage (108x3.6) = 18.7kWh/100km
Average current x average voltage x time used = 20.6 kWh/100km
Average current x nominal voltage (108x3.6) x time used = 18.7kWh/100km
Battery pack is at 129mOhms which is very high at +10 degrees but I guess it is due to the high SOC.
Which SOH are you using as reference ? min/max/avg ? I'm using for my energy calculation the min but I don't know if I'm too conservative.
I was not happy with the calculations of the internal resistance of the battery and found a more robust way to calculate it.
dU : derivate of voltage
dI : derivate of current
dt : derivate of time
R : internal resistance of battery pack
The internal reistance is found by R = dU/dI but this is very noisy and not robust
An alternative is to look at the rms voltages where R = AC voltage/AC current but that was not accurate
So instead I did linear regression on R = dU/dI = (dU/dt) / (dI/dt)
The internal resistance is the slope and R = 63mOhms, a single cell is then on average 2.3 mOhms at 10 degrees
While I am at it, I can look at the recuperated energy:
This may be fun for those who live in mountainous regions. Total energy used was 20kWh, If I drive in the opposite direction I would not recuperate energy and the predicted energy usage would be 20 + 2 x 2.5 = 25kWh which is pretty accurate.
IPace SE++, MY20, 18" summer & winter, no panoroof, towbar, spare wheel, 20C, TCU 19.2, BECS: BPAAEBCACBE