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How to: Model 3 Constant 12V for Dashcam

rohan3au

Member
Oct 27, 2017
367
639
Newcastle, Australia
Hey all, I did some searching and can't find a to-the-point post on getting a constant 12V feed that's easy to get to for a dashcam, so here it is.

Remove the front domelight / hazard switch / microphone housing using plastic trim removal tools, it can be tricky to get out, be patient. The grey facia is just a cover and the module is actually black plastic, be careful not to rip the grey cover off the module.

Once off, disconnect the black wiring connector, this is where you can find your constant power and ground reference.

- The yellow cable offers +13.4V when the car is awake and +9V when the car is asleep.
- The thick black wire third from the right in my image below is a ground reference. Be aware there is another thinner black wire on the connector that is not a ground reference.

You can then run the cable between the headliner and windscreen to your dashcam as seen in the second picture.

Things to note:
Since installing in December, I haven't noticed any battery drain on the main pack caused by the dashcam being constantly powered. As the Blackvue 650S I've installed goes into "parking mode" after a period of no motion, the camera draws little power, enough to use motion detection to start recording if something is picked up.

Make sure you check the specifications for your particular dashcam to ensure the operating voltages will work with the 13.4V to 9V range.

IMG_8562.JPG


IMG_4997.jpg
 

ewoodrick

Well-Known Member
Apr 13, 2018
5,285
3,729
Buford, GA
Note: Be careful.

I was recently at a service center and we were talking about one car that was brought in, had problems. Son had done mods to Dad's car, sound, not dashcam, but still a 12V mod.
It was causing issues with the car and had to be removed.

Tesla babysits the 12V buss and battery closely. Anything that it out of normal can cause issue. A dashcam can pull a lot of current and drain a 12V battery.
 
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Nogasmn

Member
Dec 8, 2018
232
114
Rochester
There is a much better 12v source that does not involve any in car electronics. There is a youtube video, I linked it below, out there explaining how to get to it. I would remove what you did before the car realizes what you are doing and throws a fit.
 
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Watts_Up

Active Member
Mar 4, 2019
3,299
2,194
In a galaxy far, far away
There is a much better 12v source that does not involve any in car electronics. There is a youtube video, I linked it below, out there explaining how to get to it. I would remove what you did before the car realizes what you are doing and throws a fit.
This video is from August 2018, and I remember someone mentioning that the connector (see at 1:24)
didn't have any slot available on the 2020 Model 3.
 
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mooo

Member
Dec 29, 2019
8
3
here
This video is from August 2018, and I remember someone mentioning that the connector (see at 1:24)
didn't have any slot available on the 2020 Model 3.
Sort the comments by new, some of the more recent responses (as recent as 2 weeks ago) from the uploader says it can still be safely tapped.
Don't take my word for it, go read the responses.
 

lowcarbon

Member
Oct 6, 2019
19
1
UK
@James Cole you ask why bother if we have Sentry Mode? Good question. I’ve given up on Sentry Mode myself as it drains the main battery ~1mile/hr and draws way more attention to the M3 with its headlight flashes - plus footage storage is very temperamental and you can’t monitor remotely. I’ve installed a 750S-2CH which picks up my home WiFi even when parked in the street outside, plus a lot more discrete.

@rohan3au I think you are confirming the Blackvue 650S operates fine on 9V source but would be great have have this confirmed - but how did you wire the connection, as doesn’t the 650S terminate with its own 12V car adapter?

I’ve gone for a slightly less permanent but still very workable solution with my 750S-2CH by similarly running the cables neatly behind the headliner and trim (v easy once you realise the material is pliable) and using a 60,000mAh battery under the seat - not an expensive Blackvue battery. It took me a few attempts to find the right combo, but there’s a cheapish GP10 battery pack that’s is distributed under various brand names (Transcool being one) which comes with its own 12V adapter and inbuilt 12V socket.

From what I can tell the 750S-2CH (front and rear cam) consumes about 4W when in parking mode without GPS and the battery pack lasts 3 days without any recharge but I’m finding that within minimal weekly driving during a week, this setup lasts continuously and seamlessly.
 

Watts_Up

Active Member
Mar 4, 2019
3,299
2,194
In a galaxy far, far away
I’ve gone for a slightly less permanent but still very workable solution ... using a 60,000mAh battery under the seat
- not an expensive Blackvue battery. It took me a few attempts to find the right combo, but there’s a cheapish GP10 battery pack
that’s is distributed under various brand names (Transcool being one) which comes with its own 12V adapter and inbuilt 12V socket.
Does the battery pack can be charged and deliver power at the same time, or do you need to reactivate the output after charging?

Note: I tried using a 12 V Jump Start battery but this device doesn't support “pass through charging”
and it turns off the output 12 V socket when I plug the charger to an household electrical socket.

I didn't tested also if the 12 V Jump Start battery could be charged from another 12 V battery?
I imagine that you would need a converter to raise the voltage?

Another solution that I am considering is to use a small 12 V motorcycle battery connected to the 12 V auxiliary plug through a diode.
I would loose the junction voltage (0.6 V) but I wonder if this would be enough voltage for Dashcam?
The risk would be that I could not control the charging current if the small 12 V motorcycle battery is drained, and thus blows up a fuse?
 
Last edited:

rohan3au

Member
Oct 27, 2017
367
639
Newcastle, Australia
@rohan3au I think you are confirming the Blackvue 650S operates fine on 9V source but would be great have have this confirmed - but how did you wire the connection, as doesn’t the 650S terminate with its own 12V car adapter?

I cut off the cable from the 12V adapter and soldered (Australian spelling, yes) directly to the cars wiring. 650S (without a rear cam) works perfectly on the varying voltages, I haven't tested it with a rear camera installed. Has been installed since January and still working fine.
 

ElectricIAC

Devil’s Advocate
Dec 31, 2019
2,273
564
DFW
Hey all, I did some searching and can't find a to-the-point post on getting a constant 12V feed that's easy to get to for a dashcam, so here it is.

Remove the front domelight / hazard switch / microphone housing using plastic trim removal tools, it can be tricky to get out, be patient. The grey facia is just a cover and the module is actually black plastic, be careful not to rip the grey cover off the module.

Once off, disconnect the black wiring connector, this is where you can find your constant power and ground reference.

- The yellow cable offers +13.4V when the car is awake and +9V when the car is asleep.
- The thick black wire third from the right in my image below is a ground reference. Be aware there is another thinner black wire on the connector that is not a ground reference.

You can then run the cable between the headliner and windscreen to your dashcam as seen in the second picture.

Things to note:
Since installing in December, I haven't noticed any battery drain on the main pack caused by the dashcam being constantly powered. As the Blackvue 650S I've installed goes into "parking mode" after a period of no motion, the camera draws little power, enough to use motion detection to start recording if something is picked up.

Make sure you check the specifications for your particular dashcam to ensure the operating voltages will work with the 13.4V to 9V range.

View attachment 503352

View attachment 503353
Seems like a lot of trouble to go through when the charge loss is fairly minimal and SM/TC cover more angles..
 

rohan3au

Member
Oct 27, 2017
367
639
Newcastle, Australia
Seems like a lot of trouble to go through when the charge loss is fairly minimal and SM/TC cover more angles..
Did this for many reasons:
- Don't fully trust Teslas dashcam or sentry mode, I have seen loads of people having issues with footage not recording, blank files, gaps in footage.
- Sentry mode does not work when the car is under 20% charge, this covers for that.
- TeslaCam front camera is not wide enough making a huge blind spot in Teslas coverage to the left and right of the front of the vehicle. Tesla should use the wide camera to record, not the mid-range cam they currently use.
- TeslaCam does not record audio, my dashcam does. This is useful if you are pulled over by police and need the audio for whatever reason, can also be handy in the event of an accident to have an audio recording of the post-accident chatter.
 
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