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Powering a PI (and accessories) from a 12v 15A rail.

halkun

I'm getting together parts for a project that will put a Pi 3 with touch screen in my car. It's replacing the radio, but the 12v line that went to the radio has a 1A fuse, which is too low for the 2.4A power needed for the PI 3. However, under the radio is the cigarette lighter, which has a 15A fuse. Sadly, most of the 12v lighter to 5v USB adapters have a 1A limit. I'm going to need some kind of breakout that's going to power PI and it's various attachments.

 

Breaking down further -Things I need to power.

 

Raspberry Pi 3  - (5v 2.4A)

Touch Screen - ? (the pi powers it)

Pi Cam (Powered from Pi)

 

7 port USB hub (5v - 2A)

GPS module (Powers from USB hub)

External Webcam (Powers from USB hub)

 

What parts do you think will make something like this? I'll most likely be dong this in some perfboard. My guess is that I'll break out to:

-One USB (+5 and ground only @ 2.4 amps) to the  Pi/touchscreen complex and

-One wall wart "tube" power jack (5v  2A) to the USB hub.

 

Any ideas on a part list?

Parents
  • 0

    Hi Joshua,

     

    The Raspi 3 has a maximum current demand of 2.5A. The USB hub is included in the figure as are all the devices powered from it.

     

    If you don't need wifi and BlueTooth then use a Raspi 2, instead (maximum draw of 1.5 Amps).

     

    Try your desired system with a 1A mains PSU and a quarter metre USB lead and see if it works. If you can manage it, use a full powered PSU and measure the maximum current draw with a multimeter.

     

    You might well find that you can get away with a standard 12v lighter socket USB power supply. Use a very short USB cable.

Reply
  • 0

    Hi Joshua,

     

    The Raspi 3 has a maximum current demand of 2.5A. The USB hub is included in the figure as are all the devices powered from it.

     

    If you don't need wifi and BlueTooth then use a Raspi 2, instead (maximum draw of 1.5 Amps).

     

    Try your desired system with a 1A mains PSU and a quarter metre USB lead and see if it works. If you can manage it, use a full powered PSU and measure the maximum current draw with a multimeter.

     

    You might well find that you can get away with a standard 12v lighter socket USB power supply. Use a very short USB cable.

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