Freematics Forum

Hi,

When the car key is OFF, the OBD connector keeps the adapter ON all the time.

The best solution to prevent to save battery is open the adapter, disconnect the pin-16 and connect it to a (+) of the cigarette adapter?

Is there a suggestion?

I'm intersting too about a solution, because, like you, I want to keep the OBD connected to the car.

I don't know exactly if the cigarette adapter (or more globally, the car accessories power) is a good solution, because, on some car, when you start the car, the cigarette adapater power will stop a short time during ignition of the engine.
in this case, probably the OBD bus will be disturb by seeing present before and after ignition and no present during the ignition.

I have think about a solution, not tested yet.

When you power on the car (not ignition, be when you open the car, or when you put the key and power on accessories) the cigarette adapter will activate a relay (or a mosfet) to power the board from the OBD car connector.
Then the arduino (or other main board) will maintain this mosfet active during for exemple 5min. after 5min, is the car is not started, the arduino will desctivate the mosfet, and shutdown the OBD adapter and the arduino board.

The only question about the process is : is there's a risk or a problem if the OBD adapter is not power ON when connected to the car OBD connector ? what happened on the CAN bus is the electronic is connected to the bus, but not powered on ?
If someone can answer us .... It you be great ...

A easy way to detect voltage rise from around 12V to above 14V.