Solar Home Energy System
Schematic
An inexpensive alternative to kerosene lamps.
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The Appropriate Technology Collaborative
Solar Charge
Controller
The charge controller controls
voltage flowing into the battery
to make sure it doesn’t over
charge or charge at too high of
voltage. It also stops the
battery from discharging too
much. Both of these functions
extend the battery life.
The charge controller also
controls the voltage going to
the lights.
Small Scale Home Energy System to Replace Kerosene Lamps
Charge Controller
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The Appropriate Technology Collaborative
12 volt, 5 watt
solar panel
Solar Module 5W
Maximum power at STCP
max
Optimum operating
voltage
Optimum operating
Current
Open-circuit
voltage
Short-circuit
Current
5W
17V
0.29A
21.6V
A 12 volt solar panel actually makes
more than 12 volts under typical
conditions. It takes higher voltage to
charge a 12 volt battery. Electricity
flows from higher to lower potential.
The voltage controller also keeps
electricity from the battery from flowing
back into the panel at night!
0.34A
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The Appropriate Technology Collaborative
12v 1watt LED
It is important to get LEDs that
have a long life expectancy
and that have a high efficiency.
The critical units are Lumens
per Watt. This is like Miles per
Gallon. The more lumens per
watt the better.
12 volt LED lights that use only
one watt are hard to find.
We choose 1 watt LEDs for
people who are transitioning
from kerosene lamps. We get
between 90 and 120 lumens
per watt.
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The Appropriate Technology Collaborative
6 Amp Hour
12 volt battery
Capacity
77°F(25°C)
20 hours rate(0.6A 10.5V)
10 hours rate(1.14A 10.5V)
5 hours rate(2.05A 10.5V)
1 hour rate(7.5A 9.6V)
Internal Resistance
Full charged battery
77°F(25°C):
14Ah
13.4Ah
12.2Ah
9.5Ah
20mΩ
We often buy
batteries in the
country where the
solar power
system is to be
used to avoid the
expense of
shipping heavy
gear.
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The Appropriate Technology Collaborative
USB 5v Power
Supply
This converts 12
volts to 5 volts and
has a USB
connector for cell
phone charging.
Many of our clients
tell us that this is
the most important
part of the system!
Small Scale Home Energy System to Replace Kerosene Lamps
Schematic Wiring Diagram
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The Appropriate Technology Collaborative
Wiring Diagram
5 Volt USB Cell Phone
Charger
Solar Charge Controller
Switch
12v 6 amphour battery
12 volt, 5 watt
solar panel
+
Wire
Conductors
Switch
1w White
LED
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Small Scale Home Energy System to Replace Kerosene Lamps
Schematic Wiring Diagram
1w White
LED
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The Appropriate Technology Collaborative
• You can purchase complete solar lighting
systems from The Appropriate Technology
Collaborative. Just email:
info@apptechdesign.org
and include the words “Kit Solar” in the
subject line.
Small Scale Home Energy System to Replace Kerosene Lamps
Schematic Wiring Diagram
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