How to add a 12v cigarette socket in frunk (Model Y 2022)?

[chewy1337]

I have a 2022 Model Y (which has the 12v Li-Ion battery).

I would like to add a 12v accessory (cigarette) socket in the frunk so I can use it to charge my OneWheel [an electric skateboard] which I store in my frunk.

Can I simply connect a 12v accessory socket directly to the 12v battery terminals and call it a day?

(In case its relevant, my OneWheel car charger uses 12v @ 10amps, and runs for 3 hours to bring the skateboard from 0 to 100%.) I'm hoping it can charge up when I've parked the car and walked away, but if it only will charge when I'm driving or in camp mode, I'll take that as the next best thing.

 

[jcanoe]

I have a 2022 Model Y (which has the 12v Li-Ion battery).

I would like to add a 12v accessory (cigarette) socket in the frunk so I can use it to charge my OneWheel [an electric skateboard] which I store in my frunk.

Can I simply connect a 12v accessory socket directly to the 12v battery terminals and call it a day?

(In case its relevant, my OneWheel car charger uses 12v @ 10amps, and runs for 3 hours to bring the skateboard from 0 to 100%.) I'm hoping it can charge up when I've parked the car and walked away, but if it only will charge when I'm driving or in camp mode, I'll take that as the next best thing.

Store the skateboard in the rear as there is already a 12V accessory socket there. You would need to use Camp Mode so the 12V power stays active after you exit. (Manually lock the doors using the Tesla app.)

The 12V accessory port is capable of 12A continuous, 16A peak. The 12V lead-acid battery cannot provide the needed power, only the Tesla power conversion system DC-to-DC converter can supply enough power for the time needed to charge the skateboard.

 

[chewy1337]

Thanks jcanoe!

Are you saying that the accessory ports inside the Model Y are powered directly from the DC-to-DC converter, rather than from the 12v battery? If so, is there a way I can access the DC-to-DC circuit in the frunk to add an accessory port inside there?

You're totally right that the simple solution is for me to store the OneWheel in the trunk, however for a number of reasons I'm motivated to keep and power it in the frunk if I can find a way.

This person did it here (

https://www.reddit.com/r/onewheel/comments/ib5fx4

), claims it works well, but he/she didn't follow up later to update if this ever caused problems.

I saw from your post in 12v On Board DC/DC Charger that "I believe the Tesla Model Y's DC-to-DC converter's maximum output is right around 2kW" and "The Model Y will maintain the 12V battery as required even if the Model Y enters sleep mode". Wouldn't this suggest that if I attempted to pull more power than the 12V battery could continuously provide that the DC-to-DC converter would turn on and supplement the necessary power?

 

[ATPMSD]

The 12V lead-acid battery cannot provide the needed power,

Seems like a moot comment as the 12v port only functions when the car is awake, and when the car is awake the 12v system is powered by the DC-DC converter. (?)

 

[ATPMSD]

Can I simply connect a 12v accessory socket directly to the 12v battery terminals and call it a day?

No! You should never connect anything directly to the 12v battery.

 

[crazyrudy]

Here is my solution. I have soldered a tap at the rear socket location. The + wire runs through a diode that prevents power feedback to the car battery, and is connected then to the positive terminal on an Ohmu battery. That battery is then connected to a power distribution center (RigRunner) with fuses. When the car goes to sleep, the Ohmu powers all of my many accessories until I power up the car again. Works like a charm! The attached photo was taken before dressing the cables. 2023 MY DM LR.

 

[ATPMSD]

Looks cool, but it seems you are still drawing power directly from the battery and bypassing the BMS. It will be better to avoid connecting directly to the car’s battery.

 

[crazyrudy]

Looks cool, but it seems you are still drawing power directly from the battery and bypassing the BMS. It will be better to avoid connecting directly to the car’s battery.

No, I am only drawing from the car battery when the car is on. And I am drawing the power from the 12v cig socket. So NO direct connection to the battery. I have already been down the direct to battery connection road. That is a road that is very rough with 12v reset potholes. When the car sleeps, the accessories are powered by the Ohmu battery that you can see in the pictures. When the car is awake, it charges the Ohmu. The Ohmu supplies the power to the rigrunner, and then to the accessories (cameras, wireless router, inverter, etc.). Also, the BMS is not involved here. It is the left front VCU that controls the low voltage system, the BMS is controlling the high voltage system. So no BMS involvement at all except when it directs power to the LFVCU.