Ghost128k
Posts: 12
Joined: Tue Sep 19, 2017 10:59 pm

read canbus with power off

Fri Oct 25, 2019 12:44 am

Hello, i´m trying to connect the obd2 with a raspberry pi by bluetooth to read the SoC and stop the charge at a certaint % of SoC.
When the car is "ready" work perfectly, the raspberry can read the canbus through obd2 and get the SoC.
But i see that when the car is off, the conection betwen the canbus and the bms is off.
Any idea of i can power on the canbus when the j1772 is conected and the car is charge?
Many thanks in advance.

kirq4e
Posts: 9
Joined: Wed May 22, 2019 4:10 am
Location: Bulgaria

Re: read canbus with power off

Fri Oct 25, 2019 1:09 am

I monitored the charging process wit CanIon without even starting the car. I believe that when it is plugged for charging the ECU starts talking to the BMS and all parameters can be read trough OBD. I believe you should be able to read everything once the charging process starts.

What software are you going to use and how are you going to configure the Pi to read the OBD data?

I also thought about something similar but I'm not sure if it is good to disconnect the power to the charger instead of pressing the button on J1772 connector. May be there is a way to modify the connector for properly stopping the charging process.

Ghost128k
Posts: 12
Joined: Tue Sep 19, 2017 10:59 pm

Re: read canbus with power off

Fri Oct 25, 2019 1:35 am

thanks for your reply.
how i can monitorize remotely the canion?
i plug permanent the obd2 in the car, but i see that when i power off the car, canion say "not connected" in a red label.
In canion i see that there is a config option in settings tab that say "charging finished notification". in the description say "send e-mail notification on charging".
this evening when the car is begin charge, i let the phone with cannion and see if the app send me a mail when reached the soc indicated.
Also i uncheck the "auto close" option.
If i receive the mail, i see how tell with the sonoff pow to stop the charge.

Later i send you how i conect the pi with the obd2.

Many thanks in advance.

DBMandrake
Posts: 219
Joined: Mon Mar 20, 2017 4:57 am
Location: Scotland

Re: read canbus with power off

Fri Oct 25, 2019 4:42 am

As mentioned, the Canbus will be active while the car is charging even when turned off and locked, and you can definitely monitor charging with Canion, I've done it many times.

However when the charging session ends the Canbus will go quiet again and Canion will report a lost connection.
- Simon

EV: 2011 Peugeot Ion
ICE: 1997 Citroen Xantia V6

kirq4e
Posts: 9
Joined: Wed May 22, 2019 4:10 am
Location: Bulgaria

Re: read canbus with power off

Fri Oct 25, 2019 2:07 pm

CanIon is a great app and has a lot of potential. It should reconnect once the charging process starts but it depends on the phone. The dongle receives 12v while the car is shut and the Bluetooth is active, but there are no canbus messages. CanIon tries to read data but the commands it sends doesn't respond. You should experiment hot it will behave in such situations.

CanIon can notify if certain SoC is reached and also has remote monitoring with http server. Check this post: viewtopic.php?t=1762&start=570#p25809

There is a link how to setup your own server and to monitor remotely the car while CanIon is active.

There are apps for automation of some processes on Android which can be useful but require root

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