Selecting the ‘right’ type of charge controller does not mean to decide which charge controller technology is better – the PWM one or the MPPT one – but rather to estimate which type of these would be more suitable for your solar system.

A PWM (pulse width modulation) controller can be thought of as an (electronic) switch between the solar panels and the battery. During the bulk charge mode, the switch is ON. The switch is "flicked" ON and OFF as needed to hold the battery voltage at the absorption voltage. The switch is OFF at the end of absorption while the battery voltage drops to the float voltage. The switch is once again “flicked” ON and OFF as needed (pulse width modulated) to hold the battery voltage at the float voltage. On the other hand, MPPT controller could be considered to be a “smart DC-DC converter”, i.e. it drops the panel voltage down to the voltage required to charge the battery.  The current is increased in the same ratio as the voltage is dropped (ignoring heating losses in the electronics), just like a conventional step-down DC-DC converter. As for the features, the difference between PWM and MPPT can be mentioned as per below:

PWM solar charge controllers are usually better for small solar systems, up to 150Wp. On the contrary, MPPT solar charge controllers are suitable for larger solar systems with above 150Wp installed solar power.

For PWM solar charge controller, the solar panel/ array voltage should match the voltage of the battery bank. While, the voltage of the solar panel/ array can be higher than the battery bank.

PWM performs best when the battery is near the full state of charge. Meanwhile MPPT performs best when the battery is in low State Of Charge (SOC).

PWM usually performs better in the warm-sunny weather and MPPT performs well in the colder and cloudy weather.

The opportunity to expand the system is very less for the PWM solar charge controller. On the other hand, with the help of MPPT solar charge controller there's much better opportunity and chance for system expansion.

Price:

In case of desire to gain higher efficiency with larger solar system Titan Series, Titan Plus Series and Titan Star Series are highly recommended solar MPPT charge controller. Also, EverPro series PWM solar charge controller can be handy option for small solar system with moderate efficiency.