6 articles were written in March 2014:

When measuring the performance of the wireless power demo kit, I forgot to look at the efficiency. So I repeated my test series, but also measured the current consumption of the transmitter board.

I also ordered a cheap Qi receiver off eBay. Since my son has more than just a single toy I intended it to be used for other ones. Since it comes from China I did not expect to it get before a month or so, but shipping was really fast this time. So I found it in my mail on Thursday, and added it to the test series.