Solar Panels for Homebrew Projects.

I have been playing with some solar panels i got off ebay, they are 6v 1w. Its winter here currently and the sun is not as intense as it can be, so its a good time to see just what these panels can do and how close to their ratings they come. Surprisingly, pretty close to specs.


Started with a single panel checking voltage and ampers. Voltage looks good, 7v on an open circuit, and close enough to 6 under load.


Single panel was peaking about about 130ma, near enough is good enough.



Put a single panel on some very dead NiZn 1.6v per cell, cells i had laying about, and in a few hours all were reading 1.5v per cell, which was nice because I will use those cells with 2 panels in parallel to keep them charged for an Arduino Weather Station im currently building.



Next i paralleled all the panels up, not facing the sun in an ideal way or anything, voltage was close enough to 7v.


The for panels in parallel gave a nice 0.5a of current, so i got to thinking about series and parellel up 8 of these and make a nice 0.5a panel for the HB1B YouKits cw transmitter.



Series up 2 panels. 13v, perfect.


130ma, peaking 150ma in winter sun, 8 panels should give a nice 0.5a and keep the 7ah deep cycle well and truly topped up all day.


40m Band pass Filter

So i came across this schematic on Ebay for a 40m dc receiver kit, the front end looked nice so i copied it for my own project.


I am assuming that the band pass is transforming impedance also 50 ohm in and 1500 ohm out into the 612 mixer. I built mine for 50 in and out, by replacing the 270 and 18pf caps with 220 and 56pf.


Using my scope and signal gen i tuned the filter for max amplitude on 7.100mhz, and then did a sweep of the filter from 5 to 9 mhz and plotted its response on the graph above. Looked better than I expected.


Here is the filter as built on the board. Followed by a mess of failures where I was trying to add in a preamp that just kept loading up and not doing anything. Such is life.