AUTOMATIC SOLAR POWERED NIGHT LIGHT

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Introduction: AUTOMATIC SOLAR POWERED NIGHT LIGHT

About: a MAD man who fancies himself a genius

Hello friends

Thank you for your support for my previous project

Today I am going to make life hack "instructable" can save both money and time. This is the tutorial of “how to make an automatic solar powered night light”. This device can charge at daytime and work automatically at night

Step 1: Know Your Circuit

This device has three circuits. a switching circuit. a solar charging circuit with battery and a LED night light circuit

Step 2: The Switching Circuit

Switching circuit is most

important part in this system. to make the switching circuit you need

1) IRFZ44 MOFSET

2) 150K Ohm resistor (see the step 3 for more details)

3) 3 2pin PCB connecter

4) Wires

5) LDR

6) PCB BORD

Fig shows the circuit

I am using a long two core coated wire to connect the LDR to main circuit. it will help to avoid the unwanted lights from other light sores

Step 3: Calibration of the Circuit

This is the most important step

in the circuit designing. Calibration of the circuit helps to improve the sensitivity of the dark sensor

LDR is the important component of this circuit. it will act as the dark sensor. There are two methods to calibrate the LDR one pre calibration and other one is post calibration

In pre calibration we use a single resistor with pre calculated resistance. in post calibration we use a variable resistor and calibrate circuit at final stage

I am using pre calibration just because of its simplicity in India cost of a variable resistor are 5 to 10 times higher than a single resistor

For pre calibration you need to find the right resistor. For this first you need to find R max and R min of the LDR

Connect your LDR to multicenter and find the maximum resistance(R max) at day time. Repeat the step at night time and find out the minimum resistance(R min)

In my case R max is 600k and R min is 2k

To find the resistance we need I am using voltage divider equation

V out = V in x (R2/R1+R2)

V out = voltage to MOFSET Gate

V in = supply voltage (12V)

R1 = R min (2K or 2000 Ohm in my case)

R2 = R1 (I am using 150K or 150000 Ohm resistor)

12x (2000/2000+ 150000) = .150V

That means the MOFSET will stay off

Now test with R max .it is 600K or 600000 Ohm

12x (2000/2000+ 600000) = 9.5V

So the MOFSET is turn on and it switch on the light

Step 4: "Power, Light and Charging"

I am using a 12v 7Ah battery as

power source and a 12v 2W LED as light source. To charge the battery i am using 12v 6W solar panels. to reduce the cost i am using a DC to DC buck converter as charge controller. it can boost 12v to 14v and prevent reveres flow of voltage with a high capacity diode

You may wonder how this circuit work without any overcharge protection

After the one month test run i found out that these solar panels can’t fully charge the battery. Due to low current, battery needs 18 hours to fully charge the battery but sunlight is only available for 12 house max. in conclusion at the night time the switching circuit and LED light consume 10 to 12w of power from battery and at day time the solar panels refill the battery. Little bit tricky but its work!

Step 5: Fitting and Wiring

The fig shows the circuit of whole system

Step 6: The Moment of Truth

If everything is correct the circuit switch on the light at night and switch off and charge at the battery at day time. Just fix everything on a safe place and it work automatically

Step 7: Sum Ting More

if you want more powerful light just replace 12V LED with a 12V relay and connect that relay to ac power sources

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    22 Discussions

    0
    Sue Ann Herrera
    Sue Ann Herrera

    Question 1 year ago on Step 4

    Hi i would like to inquire how the DC-DC power boost module is connected to the switching circuit?? is that considered as the charge controller? and can you provide me the total circuit diagram including the step 4?

    0
    Sue Ann Herrera
    Sue Ann Herrera

    1 year ago

    Where is the step 4 pcb in the moment of truth video?

    0
    Arun aaron
    Arun aaron

    2 years ago

    Can you please add me in that group?

    0
    zahir1997
    zahir1997

    2 years ago

    this circuit still need to connect to the ac power supply or from the solar panel

    0
    vina1991
    vina1991

    Reply 2 years ago

    this circuit is designed for solar

    0
    AbdulM161
    AbdulM161

    2 years ago

    What is the watts of Solar panel with charging an 7.8ah battery

    0
    vina1991
    vina1991

    Reply 2 years ago

    you need a solar panel can produce more than 10w,i recommend 15w

    0
    pristlin
    pristlin

    3 years ago

    how much does it cost

    0
    vihan vikas
    vihan vikas

    4 years ago

    hii.vina

    can u tell me what is the total cost of this solar project

    0
    Mannoj22
    Mannoj22

    4 years ago

    How long can this LED light glow?

    0
    vina1991
    vina1991

    Reply 4 years ago

    Full night,about 12 hours

    0
    RadithyaA
    RadithyaA

    4 years ago

    Where do you Buy That???

    0
    vina1991
    vina1991

    Reply 4 years ago

    WHAT?

    1
    yashkhanvilkar
    yashkhanvilkar

    4 years ago

    that's just what i was looking for :)

    0
    vina1991
    vina1991

    Reply 4 years ago

    thank you for your positive feedback :)

    this is a cheap but effective night light circuit

    0
    momoluv
    momoluv

    4 years ago

    Nice job

    0
    vina1991
    vina1991

    Reply 4 years ago

    thank you for your positive feedback :)

    0
    vharish
    vharish

    4 years ago

    where you purchased solar panel, online ? if so please share details ..

    0
    vina1991
    vina1991

    Reply 4 years ago

    actually that solar panes are the gift of my old collage friend.he have a dream for making solar lights for poor who cannot afford electricity. unfortunately he fail to fulfill his dream do to sum political problems.so he give me 5 of his solar panel for free

    you can find same type of solar panels from ebay or amazon