Raspberry Pi Zero - split power

Question

Given that the RPi Zero consumes about 1A, and I have a power adapter that gives 2.4A of DC output - I'd like to use the spare ~1.4A to power up some stuff on the throughhole board.

Will that be sufficient if I will simply solder the single micro-USB female socket onto the board, and then route the parallel connection for RPi USB (using male socket for simplicity - don't want to screw up the RPi) and power rails om my board?

Any precautions, like including some resistors in the power tracks to prevent overloading?

The desired result - I will have the single power input for everything, and still be able to use the data OTG mode at my pi, if necessary.

Answer 1

You could add a fuse.

Its probably better to create a power budget so you don't go over the 2.4A mark.

(Fake numbers)

Device 1 =1a
Device 2: 50ma
Device 3: 100ma
Device 4: 200ma

Total them up, and you know won't go over because you totaled the maxes.

You could add some kind of voltage sensor, and if they voltage drops significantly say more than 5% your overloading it.

I did some more poking around and found a current limiter.

https://www.maximintegrated.com/en/products/power/protection-control/protection-ics/MAX14575AL.html

Check that out.

Answer 2

I doubt that "the RPi Zero consumes about 1A" and also that the "power adapter that gives 2.4A", but putting that aside you can power devices from the 5V pins on the Expansion Header. See Raspberry Pi Power Limitations No one really knows how much current the traces on the Pi will carry.

Using a fuse, or worse a resistor will not help; indeed a resistor would cause problems.

It is unclear exactly what you are proposing, but the simplest solution is to power the Pi through the 5V pins on the Expansion Header and connect your external circuitry to the same power supply. I CERTAINLY would NOT be attempting to solder anything to the Pi, except through the solder pads provided for the purpose.

Answer 3

I would say that don't mess with the pi board or alter it in any way. It could induce more problems.

You are correct that Raspberry Pi Zero takes under 1A but if your other gadget (throughhole board) draws more power, the output voltage of the adapter will drop and your pi will either become unresponsive or may restart due to under volt condition.

There is also a chance that if your other gadget has inductive load, it can cause spikes on the Raspberry Pi power line.

It is recommended to keep the power separate. Unless you have an adapter that provides two USB sockets like one below. These power adapters are cheap. Also would like to add that not all adapters deliver the power as marked.

If you still are too desperate and want to use one USB power port to power you Pi and your through hole board, you can also use a power splitter cable like below; there won't be any need to modify anything, just add a micro USB connected to your through hole board: