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Solar Panels are nothing new to us and its use has being increasing in enormous figures.  The use of solar panels varies from house-hold purposes to large commercial sectors. Solar panels rely totally on sun and its enduring light energy. It converts solar light energy to electrical energy making way to a technology of power generation that is environment friendly and is definitely a solution for the energy crisis the world is facing.

This simple DIY battery charger circuit-Using Solar Energy is intended for almost all types of battery charging purposes. With this DIY battery charger circuit, we can replenish all types of batteries, like mobile battery, lead acid battery, Lithium ion and NiMh batteries. A 12 volt 5 watt solar panel is the renowned part of this circuit. This solar panel is used as the source of energy. Solar cells converts light energy directly in to electrical energy or electricity. The amount of electricity depends up on the intensity of light energy falling on the solar cells. This solar energy from the solar panel may be used for providing power to electrical equipment or this energy can be stored in appropriate storage devices for later use. Normally the most efficient way of storing electrical energy is, by using rechargeable batteries and we can use this energy depending up on our needs or applications 

Working Principle of DIY battery charger circuit-Using Solar Energy:

At extreme sun light, the 12 volt 5 watt solar panel provides around 16.5 volt at 400mA current. This solar energy from the solar panel is used to charge the battery. Mainly three voltage regulator ICs are used in this multipurpose solar charger circuit. The diode D allows current flow in only one direction. The diode acts as a one- way valve, it allows current flow from the solar panel to the battery, but it doesn’t allow the reverse of the same. Actually the diode act as a blocking diode, which prevents the power discharging of the  battery through the solar panels at night or low illumination levels. The circuit diagram of DIY battery charger circuit-Using Solar Energy is given below.

solar charger circuit

The IC1 7812 is a widely used voltage regulator IC. The IC belongs to the 78xx series of fixed linear voltage regulator ICs. The xx indicates the fixed output voltage that the IC designed to provide. The IC1 7812 provides a 12 volt and 400 mA current. Output from the IC2 is suitable for charging a Lead Acid battery (Point C). These batteries are widely used in automotive, submarines, UPS, Lighting etc. Another voltage regulator ICs are also accomplished in our DIY battery charger circuit. The IC2 7806 provides a regulated 6 Volt and IC3 7805 gives a regulated 5 Volt. Resistor R3 and R2 is used with the output pin of IC2 and IC3 respectively. This is to restrict the current from the ICs to the chargers. Since the IC2 7806 provides a regulated output of 6 volt, it may be used to recharge NiCd battery (Point B). The NiCd – Nickel Cadmium battery is a rechargeable battery. This NiCd battery used a wide range of commercial and residential applications like, calculators, Digital cameras, Photoflash equipment, Instruments etc. The integrated circuit (IC3) 7805 provides a regulated 5 volt. This can be used to charge all types of mobile phone batteries (Point A), which are normally rated at 3.6 volts. The R2 limits the charging current to a safer level. From the point A we can get 5volt, this point can be used to charge batteries like Lithium ion and NiMh batteries. High value capacitors (C1 and C2) are used in the DIY battery charger circuit, which act as a current buffer. So if there is any interruption in the current flow from the panel, it will not affect the entire charging process. There is a red LED used in the circuit and it is used to indicate the charging process.  

Electronic Components:

  • Solar panel: 12volt 5Watt
  • Voltage Regulator IC1:7812 IC
  • Voltage Regulator IC2:7806 IC
  • Voltage Regulator IC3:7805 IC
  • LED, Red: 1 no.
  • Diode, D: 1N 5204/1N 5402


  • R1: 1K
  • R2: 47 ohm
  • R3: 47 Ohm


  • C1: 4700uF
  • C2: 4700uF

NOTE: If you want to know more simple and interesting Mobile Phone battery charging DIY Projects and techniques just go through,

User Review (4)

Charl Marais   Johannesburg,Gauteng

Something seems to be wrong here. As far as I know you need the carging voltage to be higher than the rated voltage of the battery in order for the battery to charge. 12 V lead acid batteries are normally charged at around 14V. With this cicuit you seem to have a 12V output to charge a 12V battery. Would this not cause the battery to remain under charged, only reaching a charged level of around 11V or so?

Reply  Report Abuse   17 December,2015 07:12

Abraham Alexander   cochin,Kerala

does there is a difference if we are using a solar panel of 12v 10w

Reply  Report Abuse   17 March,2015 11:03

Abraham Alexander   cochin,Kerala

does there is a difference if we are using a solar panel of 12v 10w

Reply  Report Abuse   17 March,2015 11:03


Hi Abraham, we know that Power,P =VI, so I=P/V. according to this equation if we are using 12V 10W solar panel, then there must be change in the current i.e Amperes. So you should change the regulator ICs according to that Ampere rating change.

Reply   Report Abuse   18 March,2015 10:03
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