Introduction: Apartment Solar System

About: I'm an Electronics Engineer who likes to make Doze Lamps, Lumen Powered Thingamajigs, Almighty Brainy Buttons, Tweeting Weather Stations and share them on Instructables.

This is a 'Green' and eco-friendly Instructable which creates a sustainable way of living which combines the use of Solar & BATTERIES. For example, the materials/ parts used do not consume electricity inorder to function. Instead it generates Clean Electricity from the Sun. No electricity is needed when it's not in use and in stand-by mode. The entire circuit is easy to repair, individual parts can be reused and also recycled down the line.

What is a Solar System?

A Solar System is a system which converts light energy into electrical energy, stores this electrical energy and also consumes this stored energy.

Main Requirement:


Why Solar?

Unlike Petrol, Solar energy from the Sun is free of cost and you dont pay taxes on it. The prices of fuel will always increase, but as production of solar panels increase the price of these panels shall decrease. You can store the converted solar energy in a BATTERY. A solar system can be assembled in any OUTDOOR WORKSHOP. Solar Energy is a Green Energy, its a Renewable Source of Energy and its good for our planet. And as long as the sun shines your system will be powered.

Step 1: Things You Will Need

Electrical Components:


Step 2: Circuit Diagram

Follow the connections in the circuit diagram. The Red wires are Positive, Black are Negative. The Red wire between the Inverter and Plug Point is Live, Black is Neutral and Green is Ground or Earthing.

Be Careful while making connections. Do not switch anything ON while connecting all the parts and components.

Do not interchange the polarity and stick to the colour coding of the wires- Red, Black & Green.

Cut all the wires to length using the wire cutter and strip the PVC covering of the ends of the wire using the wire stripper.

Step 3: Solar Panel Connections


  1. Solar Panel Connections

The Solar Panel is the device which converts the light emitted by the Sun into electrical energy. When the suns rays fall onto the solar cells, the electrons in the solar cells get excited and begin to flow, thus producing electrical energy.

Connect the wires to the Solar Panel. Let the Red wire be connected to the positive (+) terminal and the black wire to the negative (-) terminal.

Connect the other end of the red wire to the input of the first Circuit Breaker. Connect the other end of the black wire to the input of the second Circuit Breaker.

Tighten the screws of the terminals using a Screwdriver.

The diodes in the Solar Panel Connection Box are used to maintain the polarity of the solar panel. If the positive wire is connected i the middle terminal, the voltage is halfed.

Step 4: Circuit Breaker Connections


  1. Circuit Breaker Connections

The Circuit Breaker is a kind of Switch which switches OFF/shuts down/shuts OFF when a certain amount of current passes through it. It will shut OFF only when the current exceeds the given specified amount. E.g: 15A etc. It also shuts OFF when theres a short circuit. The reason one MUST connect the Circuit Breaker between the solar panel and the rest of the system is to prevent the entire system from lightning. Lightning can cause the battery to explode and also damage the entire system. The Circuit Breaker immediately shuts OFF when lightning strikes the Solar Panel.

Connect the output of the first Circuit Breaker to another red wire. Connect the other end of this red wire to the Charge controller.

Connect the output of the second Circuit Breaker to another black wire. Connect the other end of this black wire to the Charge controller.

Tighten the screws of the terminals using a Screwdriver.

Step 5: Charge Controller Connections


  1. Charge Controller Connections.

The Charge Controller is an electronic circuit which regulates the charging of the battery and also shows the battery level. The Charge controller prevents the battery from overcharging. Once the charge controller detects that the battery is fully charged it stops charging the battery. The charge controller also uses a voltage regulator to regulate the input voltage given from the battery inorder to give a stable constant output voltage. E.g: Consider a 12V soalr panel which is giving 12.5V. The charge controller will regulate and convert the 12.5V into a constant and stable 12V.

Connect a red wire to the output of the charge controller's positive terminal and connect the end of the wire to the positive terminal of the battery.

Connect a black wire to the output of the charge controller's negative terminal and connect the end of the wire to the negative terminal of the battery.

Tighten the screws of the terminals using a Screwdriver.

Step 6: Battery Connections


  1. Battery Terminal.
  2. Red wire connected to the Positive (+) terminal of the battery.
  3. Black wire connected to the Negative (-) terminal of the battery.

The Battery is a device which stores the electrical energy in the form of chemical energy. A Lead Acid battery contains lead acid in it. As the battery is used it releases hydrogen gas.This hydrogen gas is too little to affect humans.

Solder the battery connectors to the wires. This will ensure that the wire doesn't come out and also prevents shorting. Connect the battery connectors to the Battery terminal.

Once you have connected the terminals of the battery to the output of the charge controller, you can connect the inverter to the battery terminals too.

Connect one end of a red wire to the positive battery terminal and its other end to the positive DC terminal of the inverter.

Connect one end of a black wire to the negative battery terminal and its other end to the negative DC terminal of the inverter.

Step 7: Inverter Connections


  1. Inverter output connections.
  2. Cooling Fan of Inverter.

The Inverter is an electronic device which converts a low voltage DC input into a high voltage AC output. E.g: An inverter can convert 12VDC (from battery) into 220VAC (to appliance). An inverter is necessary if your appliances run on 220V AC.

The output of an inverter has three terminals namely Live, Neutral and Ground. Connect your Power Consumption Meter to the three terminals of the inverters output.

Step 8: Power Meter Connections


  1. Power Meter Connections.
  2. Power Meter Connections.
  3. Power Meter Readings ( 58KWh consumed).

The power consumption meter measure the running total of the amount of power-hours that have been consumed by the appliances. It is measured in Kilo Watt Hours (KWh).

Connect the output of the power meter to the Plug point connections.

TEST: Test the solar system by plugging a CFL bulb into the plug point/ socket and see if it comes on. Make sure the switches are ON and everything is connected.

Step 9: Calculations & Expanding Your Solar System

Calculations(example calculation): This is an example. Using the formulas given below larger Solar systems with higher capacities can be made. Use these calculations to expand your solar system.

Appliance Load-

Appliance Quantity Wattage Total

Light Bulb 2 10W 20W

Fan 1 20W 20W


Hence the total load is 40W.

Backup Time/ Running Time-

Now say you want to run these appliances for 4 Hours.

The total back up time will be 4 hours.

Wh-Then total Load x Hour (4hour × 40watt) = 160Wh.

Battery Amperage-

Battery Voltage= 12V & Watt Hour=160Wh

Therefore I= Watt Hour/ Battery Voltage

I=160/12= 13.33Ah ~ 14

I= 14Ah

Solar panel-

Generally a battery charging current = 10% of its AH Charging current = 1.4 A ( )

Power (W) = Current (A) X Voltage (V)

Solar panel needed = 1.4 A 12 V = 16.8 W

Charge controller-12 Volt, 1.4 Amp Thus a solar system is calculated

(System loss is not added with this measurement, so approximate 25% system loss will be added.)

Conclusion: So from calculation

1. Solar panel =20 watt (20 watt is available)

2. Battery = 12volt, 15AH (15AH, 20AH battery available)

3. Chargecontroller=12volt,2A(2Achargecontrolleravailable)

Efficiency of Solar panel: Here output power is the power we get from solar panel. Input power is proportional to the amount of light falling on the solar panel. Hence do not keep the Panel in shade.

Step 10: Caution, Safety, Things to Remember


  1. Safety Rules written on Battery.
  2. Caution and After Use rules on Battery.
  3. Charging Guide.


  1. While soldering do not touch the tip of the soldering iron.
  2. Wear Dark Glasses while installing the Solar Panel.
  3. Do not look Directly at the Sun.


  1. Keep the battery away from sparks, cigarettes, open flames, etc. These can result ion explosions.
  2. Do not throw water near the battery or inverter.
  3. Avoid metallic contact between the terminals of the battery, as this can cause short circuiting.
  4. Lead Acid batteries generate Hydrogen Gas.
  5. Do not hit, hammer or damage the battery, it contains lead acid and can leak.
  6. Make sure the output of the inverter is grounded/earthed.
  7. Do not block the vents of the cooling fan in order to prevent over heating of the inverter.
  8. Do not interchange the polarity of any of the connections.

Things to Remember:

  1. Do not forget to install the Circuit Breakers.
  2. Do not switch the system on until all the connections have been made.
  3. The lead acid in the battery must be replaced at least once a year.
  4. Do not switch on the inverter if the charge controller is displaying the 'Overload' signal.
  5. Always use low consumption appliances such as CFL or LED bulbs.

After Use:

  1. This battery contains lead acid and sulphuric acid. Do not just through it in the garbage as it is hazardous to the environment.
  2. At the end of the battery life, return the battery to the authorised dealer for disposal.

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