Elenco Green Projects - Manual (Page 15)

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Project #3 Best Charging Circuits
Your rechargeable battery (B4) will need to be recharged often; use
any of these circuits. Place the solar cell in sunlight or about 12
inches from an incandescent light bulb of 60W or more. It takes a
few hours to charge 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 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 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.
Best angle adjustment to light
source with voltage measurement:
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.
5V
Best angle adjustment to light source: Minimum parts: 1 2 3
ASSEMBLING PIVOT STAND
1 2 3
Place base on
flat level surface. Snap ball
on pivot
post into
pivot top.
Insert post
into base.