MPPT Solar Charge Controller is Best for RV Solar Power System

It is common that to install solar panel for RV. The whole RV solar power system consists of photovoltaic module, solar charge controller, storage battery and curcuit breaker.

The solar charge controller does not cost much in installing. It serves as the command center of RV solar power system and plays a significant role.

 

So, why do we choose the solar charge controller? This article will introduce the main solar charge controllers in the market as well as the operating principle and advantages of MPPT solar charge controller.

 

The main solar charge controllers in the market include general solar charge controller, PWM solar charge controller and MPPT solar charge controller.

 

 

General solar charge controller is the first generation technology product. It works by directly connecting the output port of solar panel to the battery port and starting charging. When the storage battery is full charged, it will interrupt the charging current. However, it is difficult to fully charge the storage battery due to the internal resistance. Therefore, the solar panel can not be made full use. And this kind of product has gradually withdrawn from the market.

PWM solar charge controller is the second generation technology product, which has obtained the most market share at present. The operating principle is PWM module. It is more excellent than the general solar charge controller in working out the problem of not fully charging the battery. However, the solar panel also can not be made full use.

MPPT solar charge controller is the third generation technology product as well as the most highest level solar charge controller.

 

A MPPT solar charge controller is the charge controller embedded with MPPT algorithm, which is the upgraded product of PWM solar charge controller.

 

MPPT solar charge controller can detect the voltage and current of solar panel in real time and continually track the maximum power point in order to reach the maximum efficiency for charging the storage battery. The MPPT tracking efficiency is 99 percent and the generating efficiency of the whole system is up to 97 percent. The battery is managed and protected well. The charging modes are divided into MPPT charge, constant voltage equalizaing charge and constant voltage floating charge. When charging the storage battery, the output voltage of solar panel are supposed to be higher than the current voltage of battery. If the voltage of solar panel is lower than the voltage of battery, the output current will be close to 0.

 

Therefore, for the sake of safety, the peak voltage of 12V solar panel was set at 17V before delivery which meets the standard of 25℃ environment temperature.

 

When it is hot, the peak voltage of solar panel will reduce to around 15V. But in the cold days, it will raise to 18V.

The output of photovoltaic array is non-linear. It is influenced by sunlight intensity, environment temperature and load condition.

 

In the condition of constant sunlight intensity and environment temperature, photovoltaic array can work at different output voltages. However, the output efficiency of photovoltaic array will reach the maximum at only one output voltage. At this moment, the operating point of photovoltaic array reaches the maximum point of output efficiency voltage curve, which is called "maximum power point."

 

Therefore, it is important to adjust the operating point of photovoltaic array and keep it close to the maximum power point so as to raising the whole efficiency of photovoltaic power system. This process is called "maximum power point tracking."

 

Now, let's compare MPPT solar charge controller with the general solar charge controller.

 

The general solar charge controller is like the gearbox of manual car. If the gear of gearbox was not been raised accordingly while the engine speed raised, it would definitely affect the speed of vehicle.

 

The charging parameters of the general solar charge controller have been set before delivery. However, MPPT solar charge controller will track the maximum power point of solar panel in real time in order to reach the maximum efficiency. When tracking the maximum power point, the higher the voltage, the more the output power and the higher the charging efficiency.

 

The efficiency of solar power system embedded with MPPT solar charge controller is 50 percent more than those embedded with general solar charge controller theoretically. Nevertheless, according to practical evaluation, this figure only comes to 20 percent or 30 percent due to the surrouding environment and energy loss.

 

In conclusion, the area of solar panel installed in RV will be limited because of the installation cost. Besides, there will be efficiency loss to a large extent because the solar panel of RV is flatly installed.

 

Therefore, it is vital to choose a suitable solar charge controller in order to reach the highest efficiency of RV solar power system.