MPPT SOLAR CHARGE CONTROLLER By Chukwuemeka Onwuka.

Share

Charge controllers are solid-state electronic devices used in nearly every solar energy system that uses batteries.

A charge controller is used in solar systems with 12 volt, 48 volt, 96 volts, etc, battery banks to keep the battery voltage within acceptable limits.

A charge controller automatically stops electrical power when batteries become fully charged.

Charge controller capacities range from 4 to 80 A etc, and sometimes multiple charge controllers can be used in parallel for larger solar battery system.

MPPT simply means maximum power point tracking.

MPPT or Maximum Power Point Tracking is simply an algorithm that is included in charge controllers used for extracting maximum available power from PV module under certain conditions. The voltage at which PV module can produce maximum power is called ‘maximum power point’ (or peak power voltage). Maximum power varies with solar radiation, ambient temperature and solar cell temperature.

The voltage at which PV module can produce maximum power is called ‘maximum power point’ (or peak power voltage). Maximum power varies with solar radiation, ambient temperature and solar cell temperature.

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 the best power that the PV module can produce to charge the battery and converts it to the best voltage to get maximum current into the battery. It can also supply power to a DC load, which is connected directly to the battery.

That is to say:
MPPT checks output of PV module, compares it to battery voltage then fixes the best power that the PV module can produce to charge the battery and converts it to the best voltage to get maximum current into the battery. It can also supply power to a DC load, which is connected directly to the battery.

The MPPT solar charge controller is more efficient and better than the PWM solar charge controller.

The simplest MPPT charge controllers cut the power when the battery reaches a set voltage, and turn it on when a low voltage set point is reached.

Maximum power point tracking (MPPT) charge controllers optimize the voltage of the solar panel array to maximize total power output then convert that to the correct voltage to charge the battery. This process significantly increases the power from a solar array, particularly in low temperatures when battery voltage is significantly below the PV array voltage.

Most MPPT charge controllers work with higher array voltages, enabling the use of larger solar modules, which can be more economical on a cost per watt basis.

A higher voltage solar array also minimizes the required wire size between the solar panels and the charge controller.

While more expensive than PWM controllers, MPPT charge controllers can boost system performance by up to 30%.

The JP2 MPPT solar charge controller employ the latest in power electronics to regulate the battery charge by controlling the charging voltage and current from a solar panel array.

Charge controllers regulate the charge of the battery, but also prevent the battery from being over discharged which can damage the battery bank.

Charge controllers have multiple stages of control it uses to regulate different voltage and current levels. The voltage and current of a battery varies over the different stages of battery charge.

Though the amount can vary, the bulk charge usually is approximately 80%, the absorption charge is 10% with the float charge representing the balance of the battery charging process.

The bulk charging stage of the charge controllers process is the first stage used to bring the battery depth of discharge (DOD) back to 100%. The bulk charge stage happens first in in the morning after the batteries DOD has drained down since sunset the previous day. The bulk charging stage pushes as many amps into the battery bank as possible from the solar panels and gets the voltage up in the process.

The effect of a charge controller is not unlike trying to fill a cup of water from a tap. You first turn the tap on full while the cup is filling, then slowly reduce the pressure until the cup is full.

When the battery bank reaches a predetermined level known as the bulk voltage set-point, the charge is then substantially slowed.

The second stage of charge a charge controller employs is the absorption stage. After a battery system has been brought up to the bulk voltage set point, the charge controller slows down the charge rate because the battery bank cannot accept the same rapid charging pace without overheating and damaging the battery bank. At the absorption stage a battery bank is only about 80% full. The absorption charge is the function level in the process that tops off the battery bank. During the absorption stage, the charge controller holds the battery volts constant and reduces the amount of current sent into the battery. When the absorption stage is complete, the battery bank is fully charges.

The final step a charge controller performs is the float charge. Typically a charge controller enters into a float charge state when the other charge levels of the battery bank has been achieved. When the number of peak sun hours is limited, a solar charge controller may not be able to get the battery bank back to the float stage before the next cycle begins.

There is a right charge controller for every solar application. JP2 Solar consultants can help you sort through the different challenges of matching the right charge controllers to your solar system.

Always check the maximum input voltage of the MPPT solar charge controller you wish to use. The higher the better.

When using the MPPT solar charge controller, you need lesser wire size/guage for linking your solar panel to the solar charge controller.
Some MPPT charge controllers offer additional features, like charge status display and automatic battery equalization. A good example is the JP2 brand of MPPT solar charge controller with bold status display and automatic voltage selection.

CHUKWUEMEKA ONWUKA.

Share