Feedback through the cigarette/12v receptacle on my 2022 Leaf

[LeafNissan1]

Yesterday I was working on my 70mai dual dash cam system that I installed a few months ago on my 2022 Leaf SV. Rather than wiring through the OBDII port to use the parking monitor feature, I bought a 40,000mah Power Bank and a Dual USB Y Extension cable from Amazon. The idea was to supply power to the camera via the cigarette/12v receptable when the Leaf was powered on and then let the Power Bank supply power to the camera when I parked and turned the car off.

I was sitting in the car and upon completing all of my connections (I did NOT have my key fob with me) I was very surprised to hear the clicking sound of a relay activating and then the entertainment system in the car lite-up and began playing music via bluetooth from my phone just as it normally does after I first turn the car on.

Obviously since I didn't have the key with me and hadn't turned anything on, power from the Power Bank was somehow feeding-back and activating the accessory mode which allowed the entertainment system to come on and be active. At that time I did notice my 12v bluetooth battery monitor I've installed on the car, show the voltage of the 12v battery drop from 12.45v to 12v.

Anybody ever experienced this type of behavior or know what is being activated by putting power from a USB power bank to this receptacle when the vehicle is in the off position?

 

[nlspace]

The voltage of the power bank is only 5V.

 

[LeafNissan1]

The voltage of the power bank is only 5V.

Previous generations of USB are 5v, however this power bank is USB-PD which will deliver 5v to start and then the device being powered can negotiate a higher voltage, the standard being 9v, 12v and 20v.

 

[MozzoAU]

There's no blocking diode between the accessory circuit and the lighter socket so yes any voltage present on the device plugged into the socket will feed back into the accessory circuit and has the potential for problems.

 

[LeafNissan1]

There's no blocking diode between the accessory circuit and the lighter socket so yes any voltage present on the device plugged into the socket will feed back into the accessory circuit and has the potential for problems.

Yes, I agree with your assessment that obviously there is no diode to prevent feedback through that circuit.

As far as any potential problems that could occur from this, I'm not sure of what they could be, but what this means is that if one is using this receptacle to power a device, for instance in this case a dash cam, which has it's own small internal battery, that feedback could possibly occur and that battery would be discharged unless the device has it's own circuitry to prevent this.

I have noticed on occasion when the car is not driven for several days, sometimes the dash cam will lose it's setting for time and date and revert to factory defaults.

Not having a diode in this circuit is a design flaw by Nissan, especially if your assessment of "potential for problems" is correct, and everyone should be sure not to leave anything that has a battery, connected to the cigarette/12v accessory receptacle when the car is off.