Why we need Solar Charge Controllers?
When you plan to install off-grid or hybrid solar energy system – the one where you are storing the energy generated by solar panels is batteries – buying an external solar charge controller becomes absolutely necessary.
What does Solar Charge Controller do?
“In just one second, the Sun produces about 100 times as much energy as entire India used in the year 2014”
Solar panels may make power at very high voltage and current. If all that is fed directly to the battery then it may get overcharged or blast (in extreme cases).
A solar charge controller prevents this from happening. It is is placed in between the solar panels and the battery bank to regulate the charging (current and voltage) of the batteries through solar. For example if your solar panels is making 20V and the battery is of 12V then it will make sure that only 12V reaches the battery.
It also prevents the reverse flow of current from batteries to the solar panels during night-time.
Basically, without a charge controller it is not possible to safely use solar energy for charging batteries. There are two types of solar charge controllers available in the market – PWM(Pulse Width Modulation) and MPPT (Maximum Power Point Tracking).
Which One is better – PWM or MPPT?
MPPT is at least 30% more efficient than PWM i.e. with MPPT you get 30% more output of your solar power system.
Why MPPT is Better than PWM?
PWM charge controllers have been around for ages and rely on old technology. They work to match the voltage of the panel to battery voltage and pulls down the panel output voltage in doing so.
Power (measured in watts) = V (volts) x I (current measured in amps)
A 12 V, 100 W solar panel can produce up to 18V and 5.56 amps
18 x 5.56 = 100.8W
(Here we are assuming that the efficiency from solar panels is 100% which is seldom the case)
Example: If you are using a 12V, 100W solar panel with battery of 12V then that panel may make 18V during the time of peak sunshine.
However PWM will only give 12V and 5.56 current to the battery. You will get only 66W(12×5.56) from your 100W panel and the extra 6 Volts will be wasted.
PWM is dragging down the voltage of solar panel to the battery voltage.
MPPT is the latest technology meant to extract maximum from the solar panel. They operate according to the panel voltage and converts extra voltage of panel into current which increases the output from the solar system.
Example: When 12V, 100W solar panel makes 18V then it will give 12V to the battery but will also increase the current to 8.34 so that you can get full 100W (12×8.34) from the panel.
As you make more power from your existing solar panels you generate more electricity which ultimately translates into savings for you. We recommend that you go for MPPT charge controllers instead of PWM even though they are a little expensive because you will be able to recover the difference in price in no time.
Just like sine wave inverters are technologically much advanced than their older counterpart, square wave inverters, MPPT charge controller is based on latest technology and are better than PWM.
It is up to you to buy either PWM or MPPT based on your budget as we have given best possible features to Su-Kam’s PWM charge controller. However we strongly advice you to never buy low-quality charge contollers.
They may be cheap may cost you your life! There have been many instances where they cause the batteries to burst.
Visit our website to know more about our range of solar charge controllers.