• Skip to main content
  • Skip to primary sidebar

Homemade Circuit Projects

Need circuit help? Post them in the comments! I've answered over 50,000!

Blog | Categories | About | Contact | Calculators-online
You are here: Home / Solar Controller Circuits / Understanding MPPT Solar Charger
warning message: electricity is dangerous, proceed with caution
mpptIVgraph

Understanding MPPT Solar Charger

Last Updated on July 15, 2019 by Swagatam 17 Comments

Here I have explained the actual circuit concept of MPPt type of solar charger controllers and learn how do these devices work.

Table of Contents
  • What's MPPT
  • What's Maximum Power Point or Knee point

What's MPPT

MPPT stands for Maximum Power Point Tracking, a charger concept specifically intended and designed for acquiring highly efficient solar power harnessing.

Solar panels are excellent devices since they allow us to harness free electrical energy from sun, however the present devices are not very efficient with their outputs. As we all know output from solar panel directly depends the incident rays of the sun, as long as its near perpendicular on  it offers good efficiency, which keeps on deteriorating with slanting rays or dipping sun position.

The above also gets affected with overcast conditions.

Moreover a solar panel output is associated with inconsistent voltage levels which needs proper regulation in order to operate the load which is normally a lead acid battery.

Lead acid batteries or any kind of chargeable battery will require a properly rated input so that it doesn't get damaged and it gets charged optimally. For this we normally involve a charger controller in between the solar panel and the battery.

As a solar panel voltage is never constant and drops with dropping sun light, the current from the solar panel also gets weaker as the sun light intensity gets weaker.

With the above conditions if the solar panel undergoes any kind of loading directly, it's current would further go down producing inefficient outputs.

In other words the efficiency of a panel is maximum when its voltage is near the rated specified value. Therefore, as an example a 18V solar panel will operate with maximum efficiency when it's operated at 18V.

And in case the sun light gets weaker and the above voltage drops to say 16V, yet still we could operate it with maximum efficiency if we could keep the 16V volts intact and derive the output without affecting or dropping this voltage.

The below given graph suggests why and how a solar panel produces maximum efficiency when it's allowed to operate at it's maximum circumstantial voltage output.

What's Maximum Power Point or Knee point

Ordinary solar charger controllers only regulate the solar panel voltage and make it appropriate for charging the connected battery, however these do not carry out the panel regulation correctly.

Conventional charger regulator which employ linear ICs for the regulations are unable to keep the solar panel from getting loaded directly by the connected battery or the inverter or whatsoever may be connected as the load.

The above situation tends to drop the solar panel voltage accordingly making its usage inefficient because now the panel is restricted from producing the rated amount of current to the load.

So why does these linear or PWM regulator chargers are unable to avoid loading of the solar panel despite being extremely advanced, accurate and correct with their operations? How do actual MPPT chargers work?

The answer to the above issues is nowhere addressed comprehensively on the net, therefore I thought it necessary to provide with an in-depth explanation regarding the difference between ordinary charger controllers and actual MPPT.

Coming back to the above question, the answer lies in the fact that in linear regulator chargers the load is directly connected with the panel, with no intermediate buffer stage, causing inefficient power transfer and dissipation.

Whereas in MPPT drivers, the load is connected through an intermediate Buck Boost converter which efficiently alters the power conditions to the load depending upon the sunlight power on the panel, ensuring minimum loading of the panel and maximum power delivery to the load.

Basically MPPTs were developed to ensure that the net input wattage was consistently delivered to the output load regardless of the load compatibility with the panel.

How Buck Boost Topology Help MPPT Controllers to maximize Efficiency

This is primarily achieved with the help of a tracking SMPS buck boost technology.

Therefore we can say that it's the SMPS buck boost technology that forms the back bone of all MPPT designs and has provided with an extremely efficient option of configuring power regulation and supplying devices.

In MPPT charger controllers, the solar panel voltage is first converted into a high frequency equivalent pulsating voltage.

This voltage is applied into the primary of a well dimensioned compact ferrite transformer, which generates the required level of current at its secondary winding, matching the specified charging rate of the battery.

The voltage however may not be matching the battery charging voltage, therefore here an ordinary linear regulator is incorporated for fixing the voltage level correctly.

With the above set up the battery stays completely isolated from the solar panel, and gets efficiently charged even under bad weather conditions, since now the solar panel is allowed to operate without affecting or dropping its available instantaneous voltage under any given condition.

This helps to implement the intended maximum power point tracking effect, which is nothing but allowing the panel to operate under minimal loading yet making sure that the connected load gets the complete power required for its optimal performance.

It would be interesting to know how an SMPS prevents the panel or any source from getting loaded directly by the load.

The secret lies behind the use of the ferrite technology. Ferrite transformers are extremely efficient magnetic devices which saturate effectively to generate an efficient conversion from input to output.

Take the example of an ordinary 2 amp iron core transformer power supply and a 2amp SMPS.   If you load the two counterparts with full current that is with 2amps, you will find the iron core voltage dropping substantially whereas the SMPS voltage dropping only marginally or rather negligibly....so this is the secret behind the effectiveness of an SMPS based MPPT compared to a linear IC based MPPT charger controller.

You'll also like:

  • 1.  How to Make a Solar Panel Optimizer Circuit
  • 2.  High Efficiency Solar Charger Circuits using Switching Regulators
  • 3.  How to Design a Solar Inverter Circuit
  • 4.  PWM Solar Battery Charger Circuit
  • 5.  Single LM317 based MPPT Simulator Circuit
  • 6.  Zero Drop LDO Solar Charger Circuit

Filed Under: Solar Controller Circuits Tagged With: Charger, MPPT, Solar, Understanding

About Swagatam

I am an electronics engineer and doing practical hands-on work from more than 15 years now. Building real circuits, testing them and also making PCB layouts by myself. I really love doing all these things like inventing something new, designing electronics and also helping other people like hobby guys who want to make their own cool circuits at home.

And that is the main reason why I started this website homemade-circuits.com, to share different types of circuit ideas..

If you are having any kind of doubt or question related to circuits then just write down your question in the comment box below, I am like always checking, so I guarantee I will reply you for sure!

Previous Post: « Motorcycle Low Battery Over Discharge Protector Circuit
Next Post: Convert SMPS into a Solar Charger »
Subscribe
Notify of
guest
guest
17 Comments
Inline Feedbacks
View all comments

Primary Sidebar

circuit simulator image

Subscribe to get New Circuits in your Email

Categories

  • Arduino Projects (90)
  • Audio and Amplifier Projects (132)
  • Automation Projects (17)
  • Automobile Electronics (101)
  • Battery Charger Circuits (84)
  • Datasheets and Components (105)
  • Electronics Theory (140)
  • Free Energy (38)
  • Games and Sports Projects (11)
  • Grid and 3-Phase (19)
  • Health related Projects (25)
  • Home Electrical Circuits (12)
  • Indicator Circuits (15)
  • Inverter Circuits (89)
  • Lamps and Lights (142)
  • Meters and Testers (71)
  • Mini Projects (46)
  • Motor Controller (64)
  • Oscillator Circuits (28)
  • Pets and Pests (15)
  • Power Supply Circuits (89)
  • Remote Control Circuits (50)
  • Security and Alarm (64)
  • Sensors and Detectors (103)
  • SMPS and Converters (31)
  • Solar Controller Circuits (60)
  • Temperature Controllers (42)
  • Timer and Delay Relay (49)
  • Transmitter Circuits (29)
  • Voltage Control and Protection (38)
  • Water Controller (36)

Other Links

  • Privacy Policy
  • Cookie Policy
  • Disclaimer
  • Copyright
  • Videos
  • Sitemap

People also Search

555 Circuits | 741 Circuits | LM324 Circuits | LM338 Circuits | 4017 Circuits | Ultrasonic Projects | SMPS Projects | Christmas Projects | MOSFETs | Radio Circuits | Laser Circuits | PIR Projects |

Social Profiles

  • Twitter
  • YouTube
  • Instagram
  • Pinterest
  • My Facebook-Page
  • Quora
  • Stack Exchange
  • Linkedin
  • Recent Comments

    • Swagatam on Simple Buck Converter Circuits using Transistors
    • David on Simple Buck Converter Circuits using Transistors
    • Swagatam on Clap Switch Circuits with Relay ON/OFF: [Tested]
    • Mark on Clap Switch Circuits with Relay ON/OFF: [Tested]
    • Swagatam on Boost Converter Calculator

    © 2025 · Swagatam Innovations