Meanwhile I have one of those power supply modules and tested it with a stripe of copper of an old PCB, because at 30 A the resistance of the copper gets interesting, and I have never done this before. It is 12 cm long and 1.4 cm wide, this is the test setup. The load resistance was just some 2 mm^2 flexible wire, cut until I got 46 milliohms, for 22 A at 1 V:
![](http://i.imgur.com/s8lj2QV.jpg)
I measured 7.6 milliohm for the copper stripe. With 20 A this would result in a voltage drop of 0.152 V and a power dissipation of 3 W. The power supply module gets very hot, too, needed a fan.
The temperature of the copper stripe, shot with my new Fluke VT02:
![](http://i.imgur.com/bL1h61r.png)
Maybe I can use some wider traces and 70 um instead of 35 um copper. And the sense-pin of the power module helps a bit, but still a problem if one Avalon chip is up to 20 cm apart the other chip, which is important because of the low core voltage of 0.9 V. But this could be solved with soldering some silver wires on top of the traces. Just in case I'll remove the solder stop mask for it when creating the PCB. Maybe this is one reason that many other mining boards are using 4 layers?
Next week I'll get the PIC (it is available in SMD and DIP) to do some tests on a breadboard before I finish the Eagle schematic.
I don't think that the Seebeck effect would produce much more power than needed to light a LED, the efficiency is only 1-2%. Would be better to power some Stirling motor with the waste heat
![Smiley :)](https://www.eevblog.com/forum/Smileys/default/xsmiley.gif.pagespeed.ic.R8GFI-pF6f.png)
BTW: the "SmartView" software for the VT02 is crap. First it didn't install on my PC and I had to search the temporary files to start the installation program manually. And when exporting an image, it doesn't export the scale on the right side properly (missing temperature numbers) and there are no useful features in the software at all. For example I would like to click with the mouse in the image and get the temperature, or adjust the image transparency overlay, as it is possible on the device. I wonder why the installation package needs 200 MB. But the device itself is nice, now they should hire some better programmers.