Which power supply for a Rasperry Pi controlling 4 stepper motors

Let's Make Robots
1

hi,
I’m looking for the easiest way to use 4 stepper motors with a raspberry pi.
(easiest = only a few soldering)
So, the MegaPi from MakeBlock looks like very interesting to me,
I’m good with coding, but I’m not with electronic…

the documentation of the MegaPi says the power supply can be between 6v to 12v.
the stepper motors from MakeBlock says also their power supplies are 12v.
So, that’s easy, I need a 12v power supply for this project.

But about the amps?
these stepper motors documentation say they need 1,7A/step.
so I need a 1,7A x 4 motors = 6,8A power supply, don’t I?

On this website, the biggest 12V battery can only deliver 2,8A .
Should I connect 3 of them to have 8,4A?
Someone has any better idea or any better product?
(the stepper motors shaft must have 4mm diameter)
Or did I misunderstand something?

Thanks

2

Hello @NekoKamiFR,

I guess you want to make something like this:

connection
connection771×538 39.1 KB

Did you already choose which stepper motor you want to use?
I guess suggestion would be:
https://www.robotshop.com/uk/makeblock-12v-075oz-in-bipolar-stepper-motor.html

These stepper motor drivers could withstand up to 2.5A but you would have to improve cooling, heat disipation.

Your calculation is ok. You should connect your batteries in parallel: https://www.batterystuff.com/kb/articles/battery-articles/battery-bank-tutorial.html

3

Wow! it was a fast answer!
Ok, you perfectly understand and answered my question.
Thanks.

Because of the price of the batteries and their capacity, I’ll look for another solution.
Probably a low power motors like the NEMA-17 12V, 350mA.
I need to figure out if it’s strong enough for my project.

4

No problem @NekoKamiFR :slight_smile:

If you want, you can share more info about your project here.

For example, what are you building, why do you need batteries, etc. :slight_smile:

5

It can be a good idea, but i should change the title of this topic…

I’m trying to build a trash can which follows my wife , opens it lid and makes an annoying sound each time she drops something on the floor.

For this very useful project , I want to use mecanum wheels (using 4 stepper motors),
a cam with Pan and Tilt that lights up the object she drops (2 servos).
And a third servo opens the lid.

Thanks for the help of all the community :laughing:

1 Like
6

:rofl::rofl::rofl::rofl:

Amazing idea :smiley:

You must put it in Robots section :sweat_smile: