Power supply voltmeter retrofit

Some time ago I was busy procrastinating about buying a laboratory power supply, due to the cost and my not wanting to pay it, when I came across the Powertech MP3800 at Jaycar. This power supply only cost $149, yet has better specs than many of the other power supplies available at twice the cost: 0-24V, 15A continuous. Not bad.

So I bought one, and it has been completely reliable. The only thing that I didn’t love was the absence of a digital volt meter. This isn’t exactly a problem, as the analogue gauge is accurate (if somewhat harder to read because they marked it strangely), and I normally just used my multimeter to check the voltage; however, I still wanted a digital gauge, and on my wanderings around eBay I saw some very cheap, LED voltmeters.

Long story short, see the pictures below of the voltmeter installed, and the brackets that I printed out to mount it off the rear power terminals.



I’m pretty happy with this, especially since the voltmeter cost less than $2.

The voltmeter was listed on eBay as a “0.36” LED Display Car Digital Voltage Voltmeter Gauge Panel 3 Wire DC 0-200V”, and comes in an assortment of LED colours (from soothing “everything’s okay” blue, to an angry “Danger Zone” red), and a selection of measurement voltage ranges.

Since the power supply can range from 0-30V, I just connected both the red (power supply) and blue (measured voltage) wires to the +ve terminal of the power supply, and the black (ground) wire to the ground terminal of the power supply.

For the 3D model of the backet that I used, check out the design on thingiverse (includes solidworks file so that you can modify it to suit your application):



One thought on “Power supply voltmeter retrofit

  1. Nice design – I’ve made myself one as well! For anyone who’s interested, I can highly recommend the MP-3800 as a reliable power supply for a RepRap 3D printer, and JayCar has it on special for only $119 in October 2015 – unbeatable value!

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