How To Make A Solar Battery Charger
Materials:
- Solar Cells
- 1 Diode
- Battery Holder
- Wire
- Soldering Iron & Solder
You will need to understand the difference between wiring in
a SERIES or in PARRALLEL. A SERIES is when each Cell
(Solar or Battery) is wired Positive to Negative to Positive
to Negative and so forth. A SERIES will increase Voltage
while maintaining Amperage.
PARRALLEL is when each Cell is wired
Positive to Positive to Positive and then Negative to
Negative to Negative. PARRALLEL increases Amperage
while maintaining Voltage.
You will need to configure the Solar Cells to produce 1.2-1.5 VDC
or Volts in Direct Current. To increase Voltage, while maintaining
Amperage, wire the Cells
in a SERIES. Three Cells producing 0.5 Volts each wired in a series
produces 1.5 Volts. The alternative to wiring in a SERIES is to
wire in PARRALLEL which will increase Amperage while maintaining
the Voltage of a single Cell. Three Cells producing 0.6MA and 0.5
Volts each wired in PARRALLEL will produces 1.8MA at 0.5 Volts.
MA stands for Millionths of an Amp.
A Diode is a one-way switch for elecrical current.
Current flows from Cathode to Anode but not Anode to Cathode.
If the band marking Cathode is not visible,
you must contact Radio-Shack to find out which
end is which. I did this but had a really hard time with their
phone support, eventually someone helped me!
Most if not all battery holders come prewired in a SERIES. You
want the batteries to be in PARRALLEL with one another. They will
currently be positive to negative to positive to negative, etc..
You want them to be positve to positive to positive and then negative
to negative to negative.
Radio Shack sells a Silicon Solar Cell which is 2x4cm and delivers
0.3amp at 0.55VDC. We want the Voltage to be 1.2-1.5V so we will
take 3 of these and wire them in a SERIES to give 0.3 amps at
1.65 volts. If we wanted more Amperage, we would wire another
set of 3 Cells and wire the 2 sets together in PARRALLEL to produce
0.6 amps at 1.65 volts.
To wire the Solar Charger together, you will put the diode on the
negative wire between the Solar Cells and the Battery Cells.
The Negative wire on the Solar Cells should be soldered to the
Cathode and then the Anode should be soldered to the Negative
wire of the Battery (holder). So the one-way current is from
Solar Cells to Battery Cells which is Cathode to Anode.
The positive wire on the Solar Cells will be connected directly
to the positive wire on the Battery Cells.
Packaging the Solar Charger is up to you. The 2x4cm cell used
in the above example is very breakable and must be protected
in some fashion. Radio Shack sells pre-packaged cells which
have a plastic case with a translucent top. They come in a
variety of Voltages and Amperage. You can modify the charger
with plugs so you can change out battery holders to different
sizes as needed.
The following is a list of Radio Shack catalog numbers and
specifications for Solar Cells.
Catalog Number
|
Specifications
|
Description
|
RSU 12037115
|
050MA at 4.0VDC
|
Flexible Solar Cell
|
RSU 11903101
|
300MA at 0.5VDC
|
Enclosed Solar Modules
|
RSU 11903085
|
200MA at 1.5VDC
|
Enclosed Solar Modules
|
RSU 11903093
|
050MA at 6.0VDC
|
Enclosed Solar Modules
|
276-124
|
0.3Amps at 0.55VDC
|
Silicon Solar Cell
|