What will do if you are in a place where AC is not available to power your gadgets ? You can carry this Portable Solar Generator to a Picnic spot where AC is not available. It lights a CFL to provide sufficient light and AC for charging Mobile Phone, Tablet etc and can even play a small CD player. Alternately you can use the unit in home during Power Outage days. It converts the 12 V DC from the battery to 220V AC to light the CFL. It has a bulb holder to fix the CFL and an AC outlet to tap AC for other purposes. It uses a simple 20 Watts CFL Driver board to converts DC to AC. The battery can be charged using a 12 V Solar panel or 12V DC Adapter. The battery used in this unit is 12V 3 Ah (3 Ampere Hour) rechargeable Lead acid battery which can power the CFL many hours.
Theoretically, the 11 Watts CFL consumes 0.050 Amps or 50 mA current in one hour.
I = P / V = 11W / 220V = 0.05 A mps
P = V x I = 220V X 0.05 A = 11W
Where P is the Power in Watts, V is the AC voltage and I is the current in Amps.
Even though the CFL consumes only 50 mA current in one hour, the CFL driver is not so much efficient and not generating pure Sine wave. Any way you can expect 5 – 6 hours back up with 3 Ah battery. If you use a 12V, 7.5 Ah UPS battery, it gives many days backup.
You need the following
1. 20 Watts CFL Driver board – 1
2. 12V 3 Ah battery – 1
3. 1K Resistor – 1
4. 22K 1 Watt Resistor – 1
5. DC Socket and Jack – 1 pair
6. Red LED – 1
7. Green LED – 1
8. AC Socket – 1
9. Bulb holder – 1
10. 12 V , 5 W Solar panel.
11. Box for enclosing
12. Some wires
See the connection diagram below
The DC socket is connected to the 12V battery directly. So when the Solar panel is plugged in, battery will charge. You can also connect a 12V 1 Amps DC adapter in the same socket for charging. From the battery, DC goes to the CFL driver board ( It is a CFL driver working in DC ) through the AC switch. So when this switch is turned on, the CFL driver gets power. It is a DC – AC converter that converts 12V DC to 220V AC. This AC is used to drive the CFL. So connect the output wires (no polarity since AC ) to the bulb holder . Solder two wires from the same points to connect with the AC socket. So AC will be available in the bulb holder as well as in the AC socket. Power from the AC socket can be used to connect the Mobile phone or Tablet charger adapter.
Two LEDs are used for visual indications. Green LED indicates battery power is Ok and going to the CFL driver board. Since it is 12V DC, 1 K series resistor is used. Red LED indicates the AC output from the CFL driver board. Since the AC voltage is 220V, a 22 K 1 watt resistor is used for the Red LED.
Connect battery. Then connect 11 watts (or 5 W , 8 W etc ) CFL in the bulb holder and switch on. CFL will light. Check the AC socket using a tester. It also gives AC voltage. Connect Mobile charger in the AC socket. Mobile will charge normally.
12 V Solar panel has an open circuit voltage of 13.5 – 16V . It is rated 5 watts and delivers 400 mA current for charging the battery. As a rule, Solar panel delivers around 80mA current per watt. So 5 watts give 400 mA.
Remember; turn on AC switch only after connecting a load such as CFL or Mobile charger. If not, the CFL driver will be damaged. So do not power the board without load.