Question on 3-wire hardwire option for dashcams

Crazy Horse

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I have had a dashcam in my car for years but it has always had only two wires connected - one to ACC power and the other to ground. So, the dashcam would only record when the car was running. Now, I want to put in a new dashcam and enable the parking mode, so I need the third wire to go to always on power.

The question I have is - does the 3rd wire connect to pin2 or pin 3 of the mini-B USB connector? I don't want to pay for a new 3 wire hardwire kit when I have a perfectly good 4 wire USB cable that I used for my existing dashcam (I simply taped off the white and green leads).

If anyone with a 3-wire hardwire install could stick a multimeter into the male mini-B connector with the car off and let me know if pin 2 or pin 3 has 5V on it , which should be the always ON connection to enable parking mode dashcam operation, I would greatly appreciate it.

Here is the pinout diagram for the USB mini-B male.

usb.png
 

Crazy Horse

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How much are they charging you for a proper three wire kit??
25 bucks. It's not the money per se. I've got a 4 wire cable in there already. All i have to do is to hook up either the green or the white to the always on connection. I hate to rip everything out and start over.
 

benzr

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25 bucks. It's not the money per se. I've got a 4 wire cable in there already. All i have to do is to hook up either the green or the white to the always on connection. I hate to rip everything out and start over.
Quick fix i would think is to just get a multi-splitter and cut the wires on that ($5) max
DONT RUIN EXISTING CABLE !!!!!

If screw up no biggie just get another multi-plug
Splitter. 😉😉

Benzr
 
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Crazy Horse

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@benzr, cutting into the wire is not the issue. I already did that for my current dashcam. I ran a standard off-the-shelf USB cable with a mini-B connector at one end that that connects into the dashcam and a standard USB A at the other. I chopped off the USB A connector and connected the bare red and black wires to ACC and ground and it has worked perfectly so far. I just left the green and white wires unused. My question is on how to use the 3rd wire needed for parking mode operation. Should I use the green or the white? I know that in my cable, the white wire hooks up to pin 2 and the green to pin 3. If anyone with an off-the-shelf 3-wire dashcam cable could let me know to which pin on the mini-B male the yellow (third) wire hooks up to, that would let me know if I should use the green wire or the red wire for the always-on 12V connection. I hate to have to rip out a perfectly functional cable and install a premade 3-wire cable.

Thanks!
 

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I wonder how standardized the pinouts are for different dashcams. The reason I mention that is sometimes I grab a dashcam and a random USB cable to test for a week or two. Sometimes it works well, sometimes I get random lockups and failures until I switch over to the factory cable.

For that reason I now make a point to stick to factory cables and power adapters and not mix and match or even use generic USB cables.

Which brand of dashcam/cable do you use? That might help us ensure compatibility when grabbing our multimeters.

On another note, what's the easiest way to actually measure the internal USB pins like that? My multimeter probes wouldn't fit inside a USB cable like that.
 

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@benzr, cutting into the wire is not the issue. I already did that for my current dashcam. I ran a standard off-the-shelf USB cable with a mini-B connector at one end that that connects into the dashcam and a standard USB A at the other. I chopped off the USB A connector and connected the bare red and black wires to ACC and ground and it has worked perfectly so far. I just left the green and white wires unused. My question is on how to use the 3rd wire needed for parking mode operation. Should I use the green or the white? I know that in my cable, the white wire hooks up to pin 2 and the green to pin 3. If anyone with an off-the-shelf 3-wire dashcam cable could let me know to which pin on the mini-B male the yellow (third) wire hooks up to, that would let me know if I should use the green wire or the red wire for the always-on 12V connection. I hate to have to rip out a perfectly functional cable and install a premade 3-wire cable.

Thanks!
Most dash cams that are designed to run on USB for power are expecting 5 volts, not 12... hence why the cables that come with them have a transformer in the plug that goes into your car power outlet and the hardwire kits have a inline box that contains a transfomer to step the 12 volts down to 5. If you connect the usb straigt to 12 volts you are putting in too much voltage and can damage the camera.
 

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I chopped off the USB A connector and connected the bare red and black wires to ACC and ground and it has worked perfectly so far.
What brand and model dashcam? Those that take a USB connection for power usually require 5V, not designed to take the straight 12V your car provides. Good dashcams include a high quality inline converter to take that nominal 12V and output clean and consistent 5V to the cam. If it’s really been taking that variable 12-ish volts like a champ, that’s surprising and impressive.

By the way, if you’re comfortable doing that, why not just hook up one of the wires and see if the 3-wire option becomes available in the menu and works properly? If it doesn’t, just switch it to the other and see.

Another feature of the proper 3-wire kits is to put a configurable voltage cutoff in line as well, so that it doesn’t accidentally drain your battery too much. You probably want to grab one of those, too. My Street Guardian models also have a max recording length time (up to 24 hours) that helps as a last resort as well, but it’s not responsive to the source vehicle voltage.
 

Crazy Horse

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What brand and model dashcam? Those that take a USB connection for power usually require 5V, not designed to take the straight 12V your car provides. Good dashcams include a high quality inline converter to take that nominal 12V and output clean and consistent 5V to the cam. If it’s really been taking that variable 12-ish volts like a champ, that’s surprising and impressive.

By the way, if you’re comfortable doing that, why not just hook up one of the wires and see if the 3-wire option becomes available in the menu and works properly? If it doesn’t, just switch it to the other and see.

Another feature of the proper 3-wire kits is to put a configurable voltage cutoff in line as well, so that it doesn’t accidentally drain your battery too much. You probably want to grab one of those, too. My Street Guardian models also have a max recording length time (up to 24 hours) that helps as a last resort as well, but it’s not responsive to the source vehicle voltage.

Thanks, yeah, I know that I need to add a 12V-5V converter in series. I already have a couple of spare converters, so no issue there.

I plan to use a Vantop H612T dashcam.

https://www.amazon.com/dp/B089SVCW1X/?tag=rdf0cd0c-20

Yeah, I realize that the proper 3-wire kit has the voltage cutoff built in. The more I think about it, if I want to set up parking mode on my dashcam, I should just get the proper wire for it. Parking mode is not *that* important for me honestly. I park in a well-protected underground garage, and I am gone on work trips days at a time, so parking mode probably has limited utility. I might just go with my 2-wire setup and forgo the parking mode for now.

Thanks!
 

Deacon

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The more I think about it, if I want to set up parking mode on my dashcam, I should just get the proper wire for it. Parking mode is not *that* important for me honestly. I park in a well-protected underground garage, and I am gone on work trips days at a time, so parking mode probably has limited utility. I might just go with my 2-wire setup and forgo the parking mode for now.
Dashcams that support parking mode generally also have different modes to minimize current draw, heat buildup, and wear on the microSD card (such as 5fps with no sound), as well as different g-sensor sensitivity such as for being very sensitive to someone who bumps into you in a parking lot that wouldn’t be appropriate for driving on the road. But if you really wanted to get something similar without jacking together your own 3-wire setup or just getting the proper manufacturer’s offering, you could always put the dashcam on constant power with a switch. Flip it on when you want it and flip it off when you don’t (such as parked in your home garage or whatever). That has the downside of relying on you to remember to manually turn it on and off, of course. You could always use a programmable or timed relay to kick on automatically and simply cut power after X amount of time as well.
 

benzr

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Dashcams that support parking mode generally also have different modes to minimize current draw, heat buildup, and wear on the microSD card (such as 5fps with no sound), as well as different g-sensor sensitivity such as for being very sensitive to someone who bumps into you in a parking lot that wouldn’t be appropriate for driving on the road. But if you really wanted to get something similar without jacking together your own 3-wire setup or just getting the proper manufacturer’s offering, you could always put the dashcam on constant power with a switch. Flip it on when you want it and flip it off when you don’t (such as parked in your home garage or whatever). That has the downside of relying on you to remember to manually turn it on and off, of course. You could always use a programmable or timed relay to kick on automatically and simply cut power after X amount of time as well.
Timed Relay is my recommendation here.
Greeeeat Idea @Deacon !!

Benzr
 

benzr

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I still think a better idea is getting the manufacturer’s 3-wire kit ;)
Yeah ... too many variables in search of a issue.

B
 

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