Wireless Charging 8.7mm Coil 300mA Power Charger 5V Output (8.7mm Coil 300mA)

This is a great little wireless transmitter and receiver! The coil is much more compact than others I have purchased. Provides a good 5v.

Didn't work, defective

For small projects only. Coils work well, give 500ma off of a 9V cell, if they are touching. About 250ma with a small distance, but realistically 90-100ma. Cables were soldered on with red/black which proved out to be +/- as tradition. The coils are extremely thin. The wires are very thick insulation with almost no exposed metal and short, so be careful stripping them. If you're comfortable around a soldering iron, these work well.

Even a few mm of distance between the two coils drops the charge transfer to almost zero. Even a pair of thin plastic cases are a stretch for this. On top of that, the coil alignment is super critical - again, a shift of a few mm makes it just not work. And, on top of that, even in the perfectly aligned, almost touching state, I was only getting about 150mA across the link. No indication on the boards of which one is TX and which is RX. On the plus side, if you don't need much power, separation, and can manage the alignment, at least it's small!