Is this power supply too much or too less?

Projects General Guidance
1

Hello, I'm building a project with the components listed below;

The pumps have to be turned on at the same time at some point. How do I determine a power supply to use? I was thinking a 12V AC 5A adapter (with an AC/DC converter). Will that be powerful enough or too much?

2

It could work but I would go for a 10 amp version in order to avoid trouble with the low voltage devices.

3

Could you explain more in depth when you say "to avoid trouble with low voltage devices". I'm confused what you mean by that...what could happen if I chose the 5A one?

4

As a thumb of rule I calculate the need for current for motors to be 10 times the settled running current. They drink a lot more when starting. That calls for 2 * 300 mA * 10 = 6 Amps.

1 Like
5

You have not mentioned using an Arduino. :astonished:

In general, you will also want a 5 V supply for the Arduino. If you have 12 V, then a switchmode "buck" converter would be appropriate.

6

Yes I am using an Arduino MEGA!

I'm new to what a buck converter is, but looking online it looks like its produces an output voltage less than it's input (makes sense). How would I connect the buck converter to the arduino and power supply?

7

DC motors 'drink' about 1.25 times more. so the correct factor is 2x with a LOT of room to spare. 10x means you will never use 80% of the capacity.

8

What power supply would you recommend for all the components? 12V 5A DC or 12V 10A DC? Could I get away with the 5A if the pumps and solenoids are running at the same time...

9

I would use a separate power supply for the pumps, and look for the peak current capabilities. The startup current will flow for just a short moment.
When using a transformator they will be able to handle that, even though the voltage may drop. And, if the pumps are controlled by software, you can avoid that they start at the same time, so that startup current does not occur at the same time (e.g. by time shift, of, say, a few 100ms). And, by separate power supply, you make sure that your Arduino does not get disturbed - but for further assessment you need to share your circuit.

10

The way i read the power.
2 motors @300 but at max power start. 400ma each.
Then 4 solenoids 1,200
So 2,000 ma required.
If that was the total load i would use 3 amp.
Adding excess for a safety margin. 5 amps.

I don't like to plan for more than 70% or less than 40%.

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