Charging 4 3.7V LiPo batteries in parallel with wireless induction charging model.

Question

Same concept as a tooth brush charger. I am stepping down 120V to 5V, with full wave rectifier and 1000uF capacitor. I'm very familiar with making transformers just not as familiar with wireless charging. I am using the stepped down power to charge 4 - 3.7V 750mAh LiPO batteries in parallel. What would be the best way to regulate battery charging, protect against over/uneven charging?

jw0752 · Answer

Hi Blake,

Keep in mind that the rectifier and capacitor (which is probably not needed for the NiMH battery in the toothbrush) are on the toothbrush side. You will need a magnetic field that is varying to induce a voltage across a wireless gap. For wireless phone charging they use a higher frequency than the 50 or 60 cps available from the mains as the higher frequency is more efficient. You might want to check out this excellent Road Test by shabaz that covers a wireless power development board.

https://www.element14.com/community/roadTestReviews/2558/l/wireless-power-design-kit-medium-power-review

This sounds like an interesting project and I look forward to how it turns out.

John

Charging 4 3.7V LiPo batteries in parallel with wireless induction charging model.

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