Vehicle Battery Drain

[Ben Ryder]

Hello all,

We have experienced an unexpected problem whilst using a device with OpenXC firmware. The problem is outlined below: 

• For our current project we are using the fleet carma openXC OBD2 dongle (CrossChasm C5). 
• We have had it plugged in our car (an Opel Astra J, 1.4 Sports Tourer) all the time for several weeks without an issue.
• However, last week we didn’t use our car for seven days and after this time the car’s battery was drained completely (like really completely, as the mechanic told us afterwards).
• We could not think of any reasons other than the dongle to be cause of the battery drain, as we did not leave lights on and only had a USB charger plugged into the vehicle (the light on the device indicates that there is no electricity on the cigarette lighter when the ignition is turned off). 

We are hoping to know whether the dongle could have been the cause. Do you have similar experiences with the OpenXC firmware? Could the dongle have connected, or tried to connect, to a Bluetooth device nearby which woke up the CAN? Are there any other possible explanations?

We have been informed from the supplier that the device is capable of entering into a low power consumption 'sleep mode', is there functionality in the OpenXC firmware that can trigger this?

Any help would be greatly appreciated!

Thanks in advance,

Ben

[Eric Marsman]

Hi Ben,

Sorry about your issue. We'll need more info on the firmware options that are selected in the programmed device. 

Where did you get it or did you compile it yourself? Are you doing recurring OBD2 requests or just listening on CAN? Provide as much detail as you can.

There are several options for power management. Look for DEFAULT_POWER_MANAGEMENT on the following page:

http://vi-firmware.openxcplatform.com/en/master/compile/makefile-opts.html

Please provide more info on the specific firmware and we can go from there.

Regards,

Eric

[Ben Ryder]

Hi Eric,

Thanks for your reply,

I'm afraid I don't know where we got the firmware from, I can ask my colleague when he returns from vacation. As far as I know we should just be listening on CAN. DEFAULT_POWER_MANAGEMENT is set to ALWAYS_ON as we previously experienced problems with the other settings where the dongle would not wake up unless it was unplugged and plugged back into the vehicle. 

Apologies, I am actually heading off on vacation myself from tomorrow, so I will take a more detailed look into the firmware options when I return!

All the best,

Ben

[Eric Marsman]

Ben,

ALWAYS_ON will definitely drain the battery. This is more of a test mode. This will not take advantage of any sleep modes or low power options in the C5. As the name describes, the device will not turn off. Confirm the details of how have the C5 programmed and try the other options. 

Regards,

Eric