The old website

What was it about?

The majority of the pages was about how to connect to the grid made for SHA2017 safely and how to build a grid yourself. Some test results on cheap Chinese DC-DC converters, some tips on how to generate electricity or heat and some user projects were explained on other pages.

Safety third, err, first!

While high voltage grids are more efficient in transporting power over long distances, it makes the system way more complex and many safety measures must be implemented to avoid shocks and risk of fire. Not the way to go on a damp camping field and inside tents. A very low voltage on the other hand is much safer, but cable losses are much greater or, to minimize those losses, cables need to be very thick and expensive. This is because, at the same power, current rises when voltage drops. A 60W laptop charges needs about 0.2A at 300V. At 12V this would be 5A, 25 times as much. Simply said, a cable can be seen as a resistor, cable loss can be calculated at P=I^2*R, for the same cable a current increase of 25 times would mean a power loss factor of 625 times more! You should therefore use much thicker cables at low voltages.

We wanted to be somewhere in the middle, safe but without to much losses. Our grid voltage was specced on 42V +/- 15%. Why 42? It's the answer to the Ultimate Question of Life, the Universe, and Everything! That and voltages below 60VDC (IEC 62368-1:ES1) are believed safe to touch in most conditions. At 42V+15% were at about 48V, leaving some room for safety systems to kick in and leaves a little bit for AC ripple too.