How MPPT works?
The major principle of MPPT is to extract the maximum available power from PV module by making them operate at the
most efficient voltage (maximum power point). That is to say:
MPPT checks output of PV module, compares it to battery voltage then fixes what is the best power that PV module can
produce to charge the battery and converts it to the best voltage to get maximum current into battery. It can also supply
power to a DC load, which is connected directly to the battery.
MPPT is most effective under these conditions:
• Cold weather, cloudy or hazy days: Normally, PV module works better at cold temperatures and MPPT is utilized to
extract maximum power available from them.
• When battery is deeply discharged: MPPT can extract more current and charge the battery if the state of charge in
the battery is lowers.
MPPT solar charge controller
A MPPT solar charge controller is the charge controller embedded with MPPT algorithm to maximize the amount of current
going into the battery from PV module.
MPPT is DC to DC converter which operates by taking DC input from PV module, changing it to AC and converting it back
to a different DC voltage and current to exactly match the PV module to the battery.
Examples of DC to DC converter are
• Boost converter is power converter which DC input voltage is less than DC output voltage. That means PV input
voltage is less than the battery voltage in system.
• Buck converter is power converter which DC input voltage is greater than DC output voltage. That means PV input
voltage is greater than the battery voltage in system.
MPPT algorithm can be applied to both of them depending on system design. Normally, for battery system voltage is equal
or less than 48 V, buck converter is useful. On the other hand, if battery system voltage is greater than 48 V, boost
converter should be chosen.
MPPT solar charge controllers are useful for off-grid solar power systems such as stand-alone solar power system, solar
home system and solar water pump system, etc.
the variations in the current-voltage characteristics of solar cell and shown by I-V curve.
• MPPT solar charge controller is necessary for any solar power systems need to extract maximum power from PV
module; it forces PV module to operate at voltage close to maximum power point to draw maximum available power.
• MPPT solar charge controller allows users to use PV module with a higher voltage output than operating voltage of
For example, if PV module has to be placed far away from charge controller and battery, its wire size must be very large to
reduce voltage drop. With a MPPT solar charge controller, users can wire PV module for 24 or 48 V (depending on charge
controller and PV modules) and bring power into 12 or 24 V battery system. This means it reduces the wire size needed
while retaining full output of PV module.
• MPPT solar charge controller reduces complexity of system while output of system is high efficiency. Additionally, it
can be applied to use with more energy sources. Since PV output power is used to control DC-DC converter directly.
• MPPT solar charge controller can be applied to other renewable energy sources such as small water turbines, wind-
power turbines, etc.
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