# How to correctly supply power to multiple 12 V devices wired in parallel?

I am an artist, building a functional miniature which contains multiple devices (3 12 V computer fans, 1 cooling pump, two LED strips totauling 14 segments of three or 42 individual lights, and 1 Peltier tile). They are currently wired in parallel. I have been using an adjustable power supply, and it works however it only works when I turn the supply up to 19 V, which I know is bad for all of the devices. This supply claims a max of 3.4 A output. I also have a power supply which provides 12 V and 6 A, which when plugged in is insufficient to power the device. I have tried calculating what the current draw of the device should be, however I am not sure what the current draw of the Peltier tile is or how to determine it, and my best estimate is the the device should use possibly 4-7 Aat 12 V. Why does it work when I give it additional voltage, and yet when using a higher amperage power supply (possibly sufficient) it doesn’t work? What would be a better hypothetical way to supply power to this device? How can I calculate the current the Peltier tile is drawing?

I am learning as much as I can about electrical engineering to safely build this object, and I know enough to hack together art objects, however I am not a professional, and I feel like I have come up against the limits of my ability to figure this out!

I do have a multimeter, which I’ve used to test the claimed voltage of my adjustable PSU, and it is accurate to what it is putting out.

• Use one PSU for the peltier, and a different PSU for everything else. Until you get yourself a multimeter, you're flying blind, so get one. It doesn't have to be the best one out there, any cheap multimeter is infinitely better than none. Commented Feb 26, 2020 at 7:56
• I should have mentioned that I have a multimeter, and when I measure the current the voltage is accurate to what the psu claims it is outputting. Commented Feb 26, 2020 at 14:35
• If you have the multimeter, I would suggest just connection the peltier tiler to the 12V 6A supply and measure the current with the multimeter as Amper-meter (nb : use the high current position if it has one (often 10A on cheap multimeters) Commented Jan 12, 2022 at 18:46
• Measure the AC voltage in addition to the DC RMS voltage. If 12 V min is supposed to work, 19 V RMS works and 12 V RMS (measured at the device that needs it) does not, then the 12V RMS may have an AC component that causes it to drop below 12V min.
– Abel
Commented May 20, 2022 at 2:39