The motherboard cannot be connected directly to an AC outlet for power. It requires a low DC voltage, either 12V or 24V depending on the board and 3D printer components. A regulated DC power supply unit will step down and rectify the AC voltage from the wall to supply a constant DC current. Most DC power supplies are metal boxes with a row of screw terminals. Three of the screw terminals take in the AC power lines, while the other terminals are the positive and negative outputs for a single DC Voltage.

Mean Well Power Supply
Figure 1: Mean Well power supply connected to AC (green, white, and black wires) and supplying 24V (red and black wires)
12V or 24V

To cut to the chase, a 24V power supply is recommended over a 12V power supply. 24V will increase the performance of the stepper motors at high speeds and lighter (higher gauge) wires can be used as the heated bed will require less current at higher voltages. Whichever voltage you decide on, it is necessary to make sure that your extruder and heated bed are compatible. Extruders are either sold as a 12V or 24V edition. The heated bed can usually accept both voltages but where the wires are connected will depend on the voltage supplied.

Current Rating

After deciding on a voltage the only other power supply consideration is the output current. The output current (A) times the voltage (V) will equal the power supply’s wattage (W). The higher the wattage the more expensive and larger the power supply will be. The wattage of your power supply will depend on how your printer is configured. Stepper motors, extruders, fans and LEDS will all draw power. The wattage of each component can be found on the manufacture’s data sheet, but a general rule of thumb is to allot 100 watts for all the electrical components in a single extruder setup except for the heated bed. The heated bed is a power hungry component and can easily consume hundreds of watts.

Quality Matters

The last thing I will say about power supplies is to buy one from a reputable company. Poorly manufactured power supplies could fry your printer motherboard. I find the manufacturer Mean Well to supply quality power supplies on a budget.

External Resources

There are a lot of different ways to successfully build a 3D printer, many of which are not covered on this website. If you want to learn more about power supplies, then click through some of the links below to external websites and forums.

Recommended Products

The table below contains parts specific to this section that Dr. D-Flo uses and recommends. Depending on your printer build these parts may or may not be compatible. It is best to use the products below as a launching point to explore similar products on the linked websites. Affiliate links may be present below (depending on the vendor).

Product Supplier Distributor Description Link
24V Power Supply - Amazon
24V Power Supply Mean Well Amazon 24V 14.6A DC, Low Profile Power Supply.
12V Power Supply - Amazon
12V Power Supply Mean Well Amazon 12V 29A DC, Low Profile Power Supply.