Best Charging Circuits

Project Number: 3

Description: Your rechargeable battery (B4) will need to be recharged often; use any of these circuits. Place the solar cell in bright sunlight or about 12 inches from an incandescent light bulb of 60W or more. It takes a few hours to recharge the battery. Fluorescent lights do not work well with solar cells. You can't hurt the battery by overcharging. Circuit #1: The solar cell is on the pivot so you can adjust it for the best angle to your light source, and uses the meter (M6) to measure the voltage. Circuit #2: The solar cell is on the pivot so you can adjust it for the best angle to your light source. Circuit #3: This uses only a few parts, so you can build many of the other circuits while charging the battery.

Snappy: Although the battery is rated as 3.6V, it may charge to as high as 4.0V. If you are monitoring the voltage using the meter, you may see the voltage quickly reach 3.6V, but this does not mean that the battery is fully charged. When the battery is discharging to power something, the voltage is nearly steady for a long while then drops off quickly. The same thing occurs when it is charging. Recharging the battery will quickly reach around 3.6V but it needs much more charging to avoid a quick drop-off when discharging. Recharge the battery for several hours.