Powering Rock Pi 4b directly from car

#1

Hi there.
My name is Peter and I come from Slovenia.

I bought my first rock pi, but I own a few raspberry pi’s.
I made a car headunit using raspberry pi with official touchscreen, and I would like to make another one with rock pi because it supports android.

And since I read that it can take 12V also I’m wondering if I can power it directly with my car that is around 12.5V
Does it need constant 12V power or can it handle fluctuations in cars voltage?
I will be using 12V DC to USB-C adapter
https://images.app.goo.gl/7AtuCo3XEcuB6CScA

#2

In theory vacuum you can power Rock Pi directly from yours car’s battery. But i would advise for you to use something like “Automobile charger with QC” example https://www.amazon.com/2019-HUSSELL-5-4A-Charger-Adapter/dp/B07J6FWK57/ref=mp_s_a_1_4?keywords=automobile+charger+qc&qid=1577181626&sr=8-4

Also your link doesn’t work

#3

In the link is simple 12V DC barrel to usbc adapter.

Will use automotive QC for safety reasons.

#4

Just out of curiosity.

1st: What did you mean when you wrote “in theory vacuum”.
2nd: Why would you advise me to use “automotive QC” and what would be the advantage over directly powering from cars main power.

Just asking because rock pi supposed to have built-in buck converter that can accept voltage up to 20V. And cars voltage is ~12.6V when running (max ~14.6V spikes when accessories are turned on and off), and can drop to about ~10V when turning on the car.

“~” is meant as “around that value” and not as AC current

#5

Please bear with me as I cannot post links or more than one image, I made an account to reply to this as I just went through the process of trying many ways to do this including a usb c QC 3.0 to cigar adapter and a power bank. as you know though the rock pi 4 can take 5-20v I had to do some research myself but I found a thread on here confirming that the usb-c port can take a direct 12v line and then the rest is history, I got to work sourcing parts and ended up with a very functional outcome.

what ended up being the best solution for me was a direct 12v (3.5a fuse) line to a programmable relay then to usb-c using a custom cable i made with some cat-5 (nothing excels like excess right?)

I now have it turn on when I start the car and run for an hour after it shuts down, and is working great!

let me know if you have any questions

12v%20to%20usbc
12v to usbc.jpg2994×1581 1.48 MB

2 Likes
#6

I have a similar thing now in my car with raspberry pi.

What operating system do you use?
How did you connect signal to the rock pi so that it knows when the ignition is on and off? In my raspberry pi car headunit I did the following.
I use 5pin 12V relays that is triggered with ACC wire. When the ignition is ON the relay is on, and vice versa. When the ignition is OFF, then GPIO23 gets connected with 3v3 pin. I have a script that is constantly monitoring GPIO23, and when it gets 3v3 it starts countdown to shutdown (currently I have it set to 58min). If ACC isnt back ON (disconnecting GPIO23 and 3v3) in that time, it shuts down raspberry pi. If ACC gets ON in that time the shutdown is canceled. When the pi shuts down there is 5V delay relay that cuts ALL power to the raspberry pi after 30 seconds.
You can go to www.bluewavestudio.io forum where my “3 relay safe shutdown” is written in detail.

#7

Ah, sorry for late answer

By theory vacuum i ment that on paper it may work, but in reality you may fry RockPi :slight_smile:

Very simple answer. Safety. Converters is good, but if my memory serves me right - any electronics doesn’t really love unstable current.