OBD2 Connection

[Shakeystevo]

Evening all.

Quick question regarding my OBD2 dongle. If I leave the dongle connected to the comms port will it drain battery when it's not running? I.e. If I leave it in overnight etc...

I've read several posts on forums saying it does and several saying it doesn't...

Any help would be appreciated.

Cheers
A




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[chelspeed]

I googled OBD2 pinouts and there is a permanent 12V supply on one pin but no ignition switched 12V supply. But in the CAN signal there will be an indication that ignition is on.

So if your dongle is clever it will sit there powered up by the permanent supply but asleep taking very little power. When the CAN says ignition is on it will burst into life and do whatever it is you want it to do.

But if your dongle is cheap and badly engineered it will be live permanently and risk flattening the battery.

I had a garmin dongle that plugged into my last car and sent OBD2 data to a display on the sat nav. I left that connected permanently for a year with no detrimental effect on the battery.

What is your dongle doing? Can you ask the supplier?

[Shakeystevo]

Thanks for that. You've deff answered the question as it's a cheap eBay one lol. I won't run the risk and just remove it. Thanks again