M2 24volt model Conversion to 2 12v Fans in Parallell

[jdacal]

First off, thanks to Ed Niesley for suggesting this. I figured I'd document my experience in case it helps other.

NOTE: This installation was done on a 24 volt Makergear M2 with the Marlin board shown. If you have a different board these instructions may not apply to you. Also remember to unplug the power cord and USB cable when doing the modification!!!

This post is to explain how to connect two 12 volt fans for the case and the extruder without having to connect them in series across 24 volts. This involves connecting a DC to DC Buck Converter to the 24 volts which currently power the series fans. Setting the output of the Buck Converter to 12 volts (I set mine at 13.5v roughly what a car battery would read). And connecting both fans to the output of the converter in parallel instead of series. The Noctua fans show that they pull .05 amps so two of them would only pull 0.1 amps. The buck converter says its rated at 2 amps and 3 amps for brief periods, so it should handle two fans with no problem at all.

These are the parts I used:

1 - DC to DC Buck Converter Adjustable Power Supply (this is the one I used: http://tinyurl.com/o32a5u7 )
2 - Noctua 40mm x 40mm x 10mm fans (if you want really quiet fans: http://tinyurl.com/ofe6ebt )
About 12" of hookup cable ( black and red preferably )
3M double sided tape
solder and a soldering iron
Digital Volt Meter to adjust the output voltage of the Buck Converter

This is the completed installation. The Buck converter I mounted on the right side wall of the case with 3M double sided tape. The blue piece on it is the adjustment for voltage.

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This is the original factory wiring. I removed the two power cables shown and ran new ones from those same connection points to the input of the Buck DC to DC Converter. Once that is done adjust the output voltage on the converter (I adjusted mine to 13.5v). Then connect both negative wires from the two fans to the negative OUTPUT of the converter and both positive cables to the positive (+) output of the converter. And that's all there is to it.

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[Tim]

Looks good!

I'll add what I said to you in an email, which is that the same converter is great to use for LED strips, which are usually rated 12V.

I don't suppose that the fans draw enough power for thermal considerations to be relevant, but make sure it isn't getting warm enough to make the double-sided sticky tape gooey.

[jdacal]

Looks good!

I'll add what I said to you in an email, which is that the same converter is great to use for LED strips, which are usually rated 12V.

I don't suppose that the fans draw enough power for thermal considerations to be relevant, but make sure it isn't getting warm enough to make the double-sided sticky tape gooey.

Good point, thanks for mentioning it. I just went and checked (its been running about an hour) and its cool to the touch. Should be ok, but for those of you doing it there are mounting holes on the board, I do recommend you use them. It's one of those "do as I say, not as I do" situations.

[jimc]

this is a good write up but i also have to ask.....would it not be easier to just use 40mm 24v fans in parallel?

[jdacal]

this is a good write up but i also have to ask.....would it not be easier to just use 40mm 24v fans in parallel?

Yes Jim, but I haven't been able to find any quieter fans than the Noctua 12 volts and they don't seem to make them in 24 volt version yet. If there is a quieter 24v out there, then yes it would be easier.