Use Pwm Instead Of Mppt On Flexible Solar Panels

The benefits of a pwm solar charge controller.

Use pwm instead of mppt on flexible solar panels.

For example if you have a 100wp solar panel generating nominal voltage 36v and nominal current 2 78 a 36v x 2 78a 100w after connecting it to a standard let s say a pwm controller it brings the voltage down to 14v while the amps will be the same as a standard controller cannot do mppt tracking as mppt solar charge regulators can. If we have two solar panels with the same voltage but different wattage there is no problem. Using an mppt controller allows much higher voltages in the cables from the panels to the solar charge controller. A pwm controller is in essence like an electric switch between the solar panels and the battery.

It works through transmitting a series of short charging pulses to your battery and the charge controller will continuously check the charging state of the battery and automatically adjusts the pulse signals to. Some on the net professed that an mppt controller simply won t work with lifepo4 batteries because the voltages are higher and an mppt s boost works off the. During our blog an introduction to off grid solar applications we have mentioned that a solar controller is an essential part for a complete solar system. On the other hand if our two solar panels have both different wattage and different voltage then parallel connection is not possible since the panel with the lowest voltage would behave like a load and would begin to absorb current instead of producing it with the.

It is especially important if you have panels with higher wattage output. Once you get above about 200 watts panel wattage a mppt charge controller is justified economically. While both have their benefits. The mppt controller then converts the excess voltage into additional amps.

Example let s say you need to harvest 500 watt hours per day and your sun hours 3 hours in winter. An mppt solar charge controller has been proven to be far more efficient than a pwm controller. Panel wattage for pwm 350 watts. Pwm in the spring of 2014 early may to be exact i set up a series of tests to compare mppt controllers to pwm controllers for charging a lifepo4 battery bank.

Simple pwm or pulse width modulation solar charge controllers have a direct connection from the solar array to the battery and use a basic rapid switch to modulate or control the battery charging. They can be wired in parallel. With a pwm charge controller used with 12v batteries the voltage from the solar panel to the charge controller typically has to be 18v. A pwm solar charge controller offers a simple user experience combined with a proven time tested design.

The panel cost for pwm is roughly 200 higher than mppt. The solar market has grown exponentially over the years there are so many options for a charge controller like pwm or mppt. Solar testing mppt vs.