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wireless charging coil size
So I bought one of these to play with:
http://www.ebay.com/itm/130935883579
The transmitter board always gets really hot and smells faintly of something burning. Is this normal? Should I use some type of heat sink?
Anyway, I discovered that you can add another coil of the same-ish size to the transmitter, and both coils will work. However, if I remove the coil and add a single coil twice the size, it does not work. I'm curious as to why. What determines how large the coil can be?
Discussions
5 years ago
You need to create a coil with around 30 MicroHenry of inductance.
Its a complicated piece of maths, but its affected by the turns^2, by the area^2 and the average coil diameter^2
If its getting hot, I'd be inclined to turn the supply volts down.
5 years ago
Hot is not right, yes, you need a heat sink.
The coils work by matching up magnetic fields - if the coils are too far off in diameter, the receiver won't "catch" the full field of the transmitter.
Reply 5 years ago
I'm wanting to do something like this (multiple little coil receivers in a larger transmitter coil):
http://www.youtube.com/watch?v=p0-_ZX2oMyI
I can put multiple tiny receiver coils in my small transmitter coil and it works, but I'm failing to scale it up a bit. How do I know if the problem is my coils not matching frequency or if my setup just can't handle the larger size?
Reply 5 years ago
Sorry, that's one for somebody else to answer.