For your viewing pleasure:
9v battery charger

I use 3 9V rechargeable batteries for my paintball gun and electronic loader. 9V battery chargers are not very common and in addition can usually charge a maximum of 1 or 2 batteries at a time, which is not very convenient. This is why I wanted to build a battery charger that can charge 3 batteries simultaneously.

There was no need for a fast charger, so charge control was not an issue because there is no risk of overload or battery damage with slow charge. Therefore the circuit is very basic.

Circuit design


The resistor value of 120 Ohm is calculated so that the charge current is 25mA. This is the recommended charge current for the 250mAh batteries I intend to use.

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Last update of this page: Mon Jun 12 21:30:02 2006