12V Pump Controller

Time to detail the Pump Controller box.  We decided to go with the 12v High Temp Solar Pumps for our system.  We knew that we wanted to grow to three pumps and the price for a Chugger or a March pump is prohibitive.

In researching the pumps, I found that they are food grade and can handle temps up to 100 degrees Celsius (212 degrees Fahrenheit).  I also noted that a lot of people using these would use an old DC power supply (wall wart) as their power supply.  It seemed to me that the failures reported were from those that used older supplies or with not enough amperage.  To try to ensure that didn’t happen to us, we got a 12v 30a regulated Power Supply from Amazon.

12v 30a Regulated Power Supply – $23.14

This power supply take AC power in, converts it, and splits it out to a terminal block with three outputs.  The clear plastic cover flips up for access to the terminals.  1, 2, and 3 are +V DC Outputs. 4, 5, and 6 are -V DC Outputs.  7 is incoming AC Ground, 8 is incoming AC Neutral and 9 is incoming AC Live.

It ships with the voltage selector switch set to 220, be sure to set it to 110 for use in the US.

The box in which this will all be installed is a 10 x 10 x 4 utility box that I found on sale at Amazon.  Then I found some switches I liked and got those.  I wanted to be able to disconnect all the pumps and move them for cleaning and such, so I got some DC Jacks to enable this.  I also ordered some low voltage wire.

10 x 10 x 4 Utility Box – $20.25
Push Button on/off switch x 3 – $22.74
Low Voltage Wire – $4.86
DC Power Jacks – 10 pack – $5.54

Once the power supply came in, it was off to The Home Depot to find screws to mount the controller inside the box.

M4-0.7 x 8mm Machine Screws – $0.67

Now let’s get started.  Here’s the box:

There was obviously something in it and I wasn’t expecting that.  Turns out, it comes with a ground screw.  You can see the mounting point for the screw in this picture too.

Well, the ground screw mount point made it impossible for me to mount the power supply at the top of the box, so I had to find a new area for mounting.


Once I knew where to mount it, I took a piece of paper and placed it on the back of the power supply.  I used a small Phillips head screwdriver and punched holes in the paper into the mounting holes of the power supply.

I placed the piece of paper in the box where I wanted to mount the power supply and marked the hole with a sharpie.  Then I drilled these holes out and screwed the power supply to the box.

I had one of these electrical box cable connectors lying around, so I used it for the AC power cord coming in.

The power cable is a computer power cable that I also had lying around.  I cut off the end that would plug in to the computer and slid it through the cable connector.

I stripped off enough of the insulation to let me work with the wires.

And I connected the wires to the power supply.  I will tell you that the picture I took earlier of the back of the power supply came in really handy when working inside the box.

I then cut some of the low power wire to the length I needed and connected it to the terminals.  If you look closely, you will see that on pins 3 and 6, there are two wires.  This is for a DC Out connection that will be constant power instead of on a switch like the other three connections.

To make things easier while working with the wires, I labeled them.

I then marked the locations for the three switches.

I bought a Radio Punch kit to make the holes for the switches, but once they arrived I noticed that the punches made holes larger than what they were marked.  So I used a 5/8″ hole saw and was really surprised at how thick the metal on this box is.  Yes, you see how thick it is, but it’s something quite different when trying to drill a 5/8″ hole through it.  Unfortunately, this led to three non-linear holes.  Damn.  Oh, well.

These are the switches I decided to go with.  There is a blue ring around the push button that will light when turned on.

Just to ensure that nothing goes too easily there are five connectors on this switch.  Of course, there were no instructions that came with the switch so…

Google to the rescue!  You can have the indicator light always on, or only on when power is on.  I chose to only have the light illuminate when the power is on.  That way, we can look at the panel to see which switch is turned on by seeing the light.  This is shown in the diagram on the top.

Notice that the diagram calls for a jumper to be soldered between two of the pins on the switch.  Doing this on the first switch proved to be a royal pain.  To make things easier, I bent the pin that is not used out of the way and then bent the two pins that are supposed to be jumped so that they touched.  There are little holes in these pins and I threaded the wire through these holes to hold the pins together and soldered in place.

Then I drilled four holes into the bottom of the box and threaded the DC Jacks into place.

Yes, four.  Three switched for the pumps and one non-switched.  This is how I wired them up.

Here they are in place:

This is the box all wired up and cable ties in place.  Remember: Neat Wires are Happy Wires!

Here’s the finished box!

Money shot!  Plugged in, turned on.


Sure, cost of the controller was a bit up there, and I could have honestly just connected the pumps straight into the power supply, but I wanted a modular solution with the ability to control the pumps with a switch.  Even so, at $77.20 to build this box, I can get two 12v pumps and still be just under the price of a single Chugger pump.  Plus having a clean 12v power connection for additional devices adds a lot of flexibility to the system.

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