# Inductive Charging Li-ion Battery

Discussion in 'General Electronics Chat' started by Anabella, Jan 14, 2010.

1. ### Anabella Thread Starter New Member

Jan 13, 2010
2
0
Good morning,
I am trying to learn about inductive charging and how feasible it is for a project that I am working on. I need an expert's opinion or any other input that might be helpful.

Theoretically, this charging method can be implemented in the device, but I need to find out the size of the secondary coil that would be placed inside the device: how big? What about the charging circuitry?

Three battery scenarios are being considered:
-Single cell 18650, 1600mAh Li-ion cylindrical battery
or
-Two 18500, 1600mAh Li-ion in parallel
or
-Two 18500, 1600mAh Li-ion in series

I understand that this may be a complex question, but any input would be greatly appreciated.

What information do I need to find out the size of the coil? How do I know if this method (inductive charging) is feasible? How long would it take to charge these batteries?

2. ### rvh002@gmail.com Active Member

May 15, 2009
118
2
I do not understand the term "inductive charging" Any battery has to be charged with DC or pulsating DC,(typically via a SCR). Maybe you should explain a bit more?

3. ### Anabella Thread Starter New Member

Jan 13, 2010
2
0
Inductive charging means that the device being charged does not have any exposed contacts and the charging occurs via electromagnetic field. The device that charges has a primary coil and the device that is being charged has a secondary coil. When they are in close proximity, energy transfers from one to the other and the batteries in the device get charged. In other words, it is a form of wireless energy transfer.

4. ### THE_RB AAC Fanatic!

Feb 11, 2008
5,435
1,305
I think you will need to build it and test it to get any significant figures.

As an easy starting point I would go to the discount store and buy one of those \$15 rechargeable electric toothbrushes that have a little inductive charger dock on the base. Then see what power you can transfer through that.

Dec 5, 2009
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