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Ever since discovering these crazy wireless LEDs I’ve been messing around with wireless charging technology. So far I’ve been a bit disappointed with what I’ve been able to do, it’s been great for making LEDs light up, but my attempts to use it for anything serious have either resulted in me burning out the transmitters, or releasing the magic smoke from the circuit I’m trying to power.

So I decided to bite the bullet and get a proper set of wireless charging PCBs. If you want to watch a full video of the experiments in this blog post then you can do so here – it’s definitely worth it!

The transmitter board I have can take 5v, 9v and 12v as input and in theory with the receiver board I have we should be able to get up to 1.5A at 5v out of it. To test this I’ve hooked the transmitter up to my USB power monitor and the receiver up to my electronic load. The USB power monitor is pretty cool, it will monitor the voltage, current and power, and it also lets me trigger the various USB Power Deliver and Quick Charge modes.

I’ve run through the three different voltage inputs with the electronic load set to different load currents and generated the following graph. What was quite interesting is that I struggled to get the 12v input to work consistently, it would often fail at quite low current loads.

With the 5v input, we get maximum efficiency of 73% at a load of 0.4Amps. With the 9v input, we get just under 70% efficiency at 1.1 amps. With the 12v input, I couldn’t get it to work consistently above 0.7Amps and the efficiency was very low. I also noticed that the receiver board was getting quite warm when the transmitted was using 12v. The board was getting up to almost 80 degrees C, which is a bit too hot for my liking. When running at 5v or 9v it only got up to about 50 degrees C.

The efficiency I’m measuring is pretty close to the listing on AliExpress – which says we should be able to get 75% – so we are facing one of those rare occasions where the listing is actually accurate!

I also tried to measure the range of the transmitter and receiver. Running at 5v I got around 1cm of range, at 9v I got around 1.5cm – 2cm of range. I didn’t try and measure the 12v range as I didn’t really trust it.

I thought it might be fun to try and run a Raspberry Pi Zero W2 with the transmitter and receiver boards. To make it a real test I’m going to run Doom on the Pi with a nice TFT screen. To check if this was even feasible I ran the Pi with it connected to my USB monito