Radar & Dash Cam Combo 12V power from Review View Mirror

[aragon_arthur]

I’m planning to tap power from the rearview mirror for both a radar detector and a dash cam. I’ve seen several posts and videos showing mirror taps for one device at a time (either a radar detector or a dash cam), but I haven’t found much information on running both from the mirror.
Is it possible and advisable to power both devices this way?
I put together a wiring diagram showing what I’m planning to do and would appreciate any feedback or concerns you might have.
I’ve also included links to the parts I’m considering.
Thoughts?

Amazon.com: Sousery 1PC RJ11 Replacement Mirror Wire Power Cord for Uniden Radar Detectors，Fits DFR7 R4 R3 R7 R8 Model(3005201U) : Electronics

Amazon.com: DC12V/24V to 5V 3A 15W USB Converter Buck Module Power Adapter DC Power Adapter Converter Buck Regulator Car Power Converter : Electronics

Low Voltage Wire Connectors Solid Connection, T Tap Wire Connectors, T Type 2 Pins Wire Splice Connectors, Solderless No Stripping 3 Way Wire Connector for LED Strip, Automotive Fits 24-20 AWG 12 Pack: Amazon.com: Tools & Home Improvement

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[SwampNut]

Both of these devices use very little power so there really should be no issue. I made a video about the job to power my Uniden R4. Those T-splice connectors are EXCELLENT and you can't do better than those. The pin taps are just fine, I think they are likely all the same. My kit came with three pin sizes, only one was a good and reliable fit.

There are links to my parts in the video description:

 

[aragon_arthur]

My 26 R1S Gen 2 is different from what I’ve seen in the posts. I don’t have the silver box/ module and I have a white plug. The devices don’t turn off after several minutes( waited for an hour and is still on) have to manually turn on and off the devices every time I leave and get in the car. Not sure if the recent update made changes to the car sleeping behavior. I’m having second thought of hardwiring the dashcam and radar to the rearview mirror because I’m worried that it will drain out the battery. Thoughts?

 

[aragon_arthur]

Update: I connected both devices today and completed the installation. I’m happy to report that the car goes to sleep mode after 2 minutes and it shuts down both the dashcam and radar detector. I think what happened yesterday was related to the recent software update and kept installing that’s why the car doesn’t go to sleep mode. Charging the car overnight and the deep sleep helped as well. Here are the photos of the final installation.

Shout out to @SwampNut & @citizen for giving me the ideas.

 

[UnsungZero_OldTimeAdMan]

Even if both devices never shut down, they shouldn't draw so much power that the 12V would be compromised. And if BMS is working, it would just manifest in higher observed vampire drain. One way to find out is to obtain or measure power draw of each device. Several consecutive days and nights and with faulty BMS failing to replenish the 12V with the HV pack, that's when you risk a dead 12V.

 

[aragon_arthur]

Thanks for your input but I don’t know how to measure the power draw.

 

[eRacer]

This is very helpful. I sourced power for my radar detector from the mirror power and the source I was using had constant power that would not go to "sleep". As a result my radar would get left on when I didn't actively turn it off. What sucks is that over time it burned in a ghost image on my radar lcd screen.

Will be opening this up this weekend to match your set up.

(One issue that Rivian claims is a result of my wiring of my radar is "phantom vehicle alarms". After the previous software update I kept receiving random "vehicle alarm" notifications after the car was in sleep mode. When the service center looked at the logs, they claimed that the alarms were a result of my radar wiring. Odd because prior to the update, I've never had this issue before. I've had my radar installed since late 2023.)

 

[UnsungZero_OldTimeAdMan]

Thanks for your input but I don’t know how to measure the power draw.

If not listed in documents for the devices, the manufacturers can probably tell you if you ask them.

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