Viofo 3 wire kit

[RGeB]

Just registered to give the answer:

The hardwire kit does not work for me because I want to use a powerbank for parking mode so that I do not drain the car battery and can record for a long time.
Btw: my viofo A119 V3 consumes 273 mAh (per hour) in driving mode and with h265 codec.

Prerequisite: you need to enable parking mode in the menu (e.g. auto event detection).

If GND is connected to USB pin 4 (ID) the cam will enter parking mode.
If VCC -> 5k Ohm resistor -> USB pin 4 (ID): the cam will enter driving mode/exit parking mode.

For this to work the cam must be first powered up in driving mode - this triggers the automatic switch by sensing the ID pin.

The switchover is instantaneous, not the motion detection based switching which also does not work.

I used three relays to perform the switchover from car battery while driving and powerbank when parked. If someone is interested I could provide a schematic.

Thanks to viofu. Based on the information provided above, I have used an even simpler wiring method described at:

Front and Rear Dashcam Installation in Rav4 Hybrid...

So far, none of the available instructions provides a full description of a safe and efficient method. The instructions below round things out. I used a Viofo A129 plus duo, but similar considerations apply to most dashcam models. Check the cameras and wires by powering them up before...

www.rav4world.com

 

[viofu]

@RGeB Thats a viable solution if the powerbank can be changed in the vehicle which is not the case for my 200 Wh beast 🙂
Only thing that is important: the powerbank must support power output while charging - I think this is called passthrough.

Btw. I measured the resistance between the ID Pin and GND, a pulldown resistor of 6.3 kOhm seems to be in place in the dashcam so in fact the relay does not need to actively connect GND to the ID pin.

 

[contractor]

HI, I'm thinking about this but from another angle:

a129pro ------- 3 wire kit¬ ---------------------------------------------------------------------------------------------------------------------------ACC.
...... . . ....... ........ . . . ........|--------12v/5v boost ------ standard 1000mah USB power bank ------5v/12v usb converter -------ACC

that way the power bank charges when car is operational, but as batt+ is not connected, the cam won't drain when off. 3 wire kit is connected to acc as normal but batt+ is connected to my powerbank via voltage conv.



Thoughts?

 

[eliz]

Thanks to viofu. Based on the information provided above, I have used an even simpler wiring method described at:

Front and Rear Dashcam Installation in Rav4 Hybrid...

So far, none of the available instructions provides a full description of a safe and efficient method. The instructions below round things out. I used a Viofo A129 plus duo, but similar considerations apply to most dashcam models. Check the cameras and wires by powering them up before...

www.rav4world.com

View attachment 55717

Any idea what is the schematic for USB-C (for the newer cameras) ?

 

[evlo]

Any news about usb-c pin it now uses?

 

[XJDHDR]

In the absence of info about how the USB-C version of the wiring kit works, I decided to find the answers.

First, here is what a USB-C port's pinout looks like:

I found the following in my tests:

• The GND pins of the connect directly to the wiring kit's black wire.
• The kit supplies 5.3V through the 4 Vbus pins.
• The parking mode signal is transmitted over one of the CC pins. It is in the form of a 5V signal: The CC pin is at 0V when parking mode is requested, and 5V otherwise.
• The actual voltage cutoff point is about 200mV higher than what the switch says.
• Parking mode signal needs the yellow wire to be in a specific state for about 5 seconds. E.g. If you have turn on the ignition, the yellow wire needs to have a continuous voltage on it for at least 5 seconds for the parking mode signal to switch off.
• Once 12V is supplied to the yellow wire, the wiring kit supplies power on the Vbus pins after 5 seconds.
• If there is no voltage on the yellow wire and battery voltage drops below the cutoff point, the wiring kit stops supplying power on Vbus after 90 seconds.
• Iq is 19mA while above the cutoff voltage and 1.5mA while below cutoff.
• Once the wiring kit is in voltage cutoff mode, changing the switch to a lower value will not make the kit start using the new cutoff value until the yellow wire receives power again.

Unfortunately, like the mini-USB version, Viofo's product violates the USB spec in a few ways:

• USB power supplies are not supposed to supply power over Vbus until it has determined the sink's requirements (this is done using the CC pins in USB-C).
• USB standard allows for a voltage of 5 ± 0.25, but 5.3V is outside that range. In practice, it's unlikely you'll find anything that can't handle an extra 100mV or so. The elevated voltage is probably to accommodate Vdrop over the long cable.
• Power supplies are supposed to never cut power to the CC pins, as the sink needs this to signal its requirements.
• Power supplies are supposed to supply a voltage to the CC pins through a pull-up resistor. This wiring kit appears to just be supplying 5V directly to it.

For these reasons, I recommend against plugging the wiring kit into anything except the dashcam. I don't think anything will be damaged by plugging it in, but you might get issues trying to power it. Your mileage may vary for power banks, depending on how they were designed.

With that said, I also intend on using a power bank between my car's battery and the dashcam. I designed this circuit to switch between using the wiring kit to power the dashcam, and the power bank. I haven't tested this circuit yet so it might not work properly. Any Electronic Engineers here may feel free to critique my work:

 

[EricSan]

Nice work! I've posted some data on the hardwire kit pinouts here and some measurements of the battery protection shut down and output voltages under load for multiple Viofo and Vantrue hardwire kits. All are very well designed power supplies and provide very robust voltage output, even at current levels that exceed their design ratings.