1.1 The principle of controlling charging difference: PWM solar charge controller charging by changing the pulse width or on-time proportion of the total time, i.e., the duty cycle of the pulse to frequency regulation, the use of appropriate control methods to keep the voltage and pulse frequency for the change. And then by adjusting the period of PWM to achieve the purpose of regulating the charging current. MPPT in the control of solar battery charging will first analyses the voltage-current characteristic curve to determine the voltage of the maximum power, in the Vmp voltage to collect the current will be converted from the current, you can ensure that the solar panel of the maximum power point.
1.2 Difference in efficiency: MPPT solar charge controller, as a new product, adopts a different technology from PWM, making it more efficient than PWM. The charging time of the solar cell will also be shorter.
1.3 Difference in adapting to the environment: If in colder conditions, i.e., the solar battery voltage is higher, the advantage of MPPT is shown because MPPT can convert the excess voltage into current, thus reducing the charging voltage of the solar battery. If in hotter conditions, PWM has a greater advantage, it does not make a large increase in the maximum power tracking point.
1.4 Difference in cost: MPPT keeps the solar panels always at the maximum power point, and the increase in applicability to the solar panel system all make based on the increase in cost. PWM has fewer components, the manufacturing process will be reduced, the labor cost is also reduced, so the overall cost of PWM will be less.
Advantages: PWM solar charge controller size is smaller, in the case of limited installation sites, PWM will reduce the use of sites, the installation of sites to maximize the benefits of PWM is an earlier R & D products, the cost will be cheaper, PWM structure is simple, the internal electronic components are fewer, will not occur larger failures, long service life and work in the process of producing less heat, reducing energy consumption.
Disadvantages: PWM solar charge controller frequency modulation process driver may produce noise although through the filter can be reduced, but in some more sensitive areas, the noise will still be inconvenient for users. Because PWN belongs to a new generation of products, the technology is not perfect, low efficiency. It is suitable for systems where the voltage of the solar panels and solar battery are not matched to each other, thus limiting the usability of PWM.
Advantages: MPPT solar charge controller belongs to the basis of PWM, coupled with further research and development, improved control efficiency. For cloudy days and cold environments still have high efficiency, MPPT for solar panels and solar battery voltage requirements, increasing the scalability of the MPPT, for the later want to increase the number of solar panels for the user, do not need to modify the solar system.
Disadvantages: As a new product, although MPPT solar charge controller has higher performance, its cost is also the reason why more users do not choose it. For some large solar systems, MPPT is a better choice, but for home use, your budget cost is enough to choose this controller as well.
Both PWM and MPPT solar charge controllers have their own advantages, MPPT is more efficient and less restricted for large solar systems, while PWM is convenient for small solar systems.
