1 Topic by ThatGuy

  • ThatGuy
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  • Registered: 2013-04-14
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Topic: Max number of fans board can handle?

Ok, so I added a 60mm cooling fan to the electronics. Piggybacked off the extruder fan with no issues, and have been running with this for a while.

Printed and installed Lawsy's Mk5 extruder tip fan and added a 40mm fan to the same circuit and during the first test the heatbed couldn't get up to temperature (hovered around 87.2 degrees), extruder heated to temperature ok. But when I clicked print, both temperatures struggled. Extruder dropped down around 185, and bed stayed at 87. I killed the print after a minute.

So, I guess I'm asking too much of the board. Would running the 60mm fan off the lighting circuit work, or is this an issue where the power supply cannot supply enough Amps to keep everything happy? I have the Sang board as far as I'm aware.

2 Reply by adrian

  • adrian
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  • From: Canberra, Australia
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Re: Max number of fans board can handle?

Which model board ? if its the Printrboard clone - it can do about 200ma via the PWM MOSFET Header.

If its an older sanguinololu and the stock power supply (which is relevant as well to the above board as well) you only have ~400ma 'spare' if you have a 12.5amp power supply. And you don't want to run it at limit.

So long story short - you can run one, MAYBE 2 fans, but you dont want them to draw more than about 300ma to avoid blowing your supply early in life.

Upgraded PSU - then the skys the limit and just tap directly to the 12v supply...

3 Reply by ThatGuy

  • ThatGuy
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Re: Max number of fans board can handle?

Yeah, I'm pretty sure I have the sanguinololu board. I got my printer in April/May this year.

Wow, so very little headroom in the selection of the power supply. Maybe if I downgrade 60mm fan to 40mm fan and just have two 40mm fans I can squeeze it in. As long as I don't blow the board I'm happy. But realistically maybe for now I just run the extra fans off a separate 12V plugpack until I find something more suitable smile It's all connected with terminal blocks for now (I knew I might have issues and have to change things around a bit). One day I will have effectively built this printer from scratch with the amount of improvements required >.<

4 Reply by ThatGuy

  • ThatGuy
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Re: Max number of fans board can handle?

Now running additional fans off a separate power supply. Next issue, extruder tip fan locally cools the bed too much and leads to warping, and drops the extruder temp to a point where the software is flagging under temperature extrusion prevented (or whatever the catch phrase is).

I guess I either drop the fan speed, or abandon the fan duct all together.