Solar Charge Controller
Solar Charge Controller MPPT and PWM A solar charge controller manages the power going into the battery bank from the solar array. It ensures that the deep cycle batteries are not overcharged during the day, and that the power doesn’t run backwards to the solar panels overnight and drain the batteries. Some charge controllers are available with additional capabilities, like lighting and load control, but managing the power is its primary job. A solar charge controller is available in two different technologies, PWM and MPPT. How they perform in a system is very different from each other. An MPPT charge controller is far more efficient than a PWM charge controller, and it is often worth it to pay the extra money. MPPT or ‘maximum power point tracking’ solar charge controllers are far more advanced than PWM controllers and enable the solar panel to operate at its optimum voltage for maximum power output. Using this clever technology, MPPT solar charge controllers can be up to 30% more efficient, depending on the battery voltage and type of solar panel connected. The reasons for the increased efficiency and how to correctly size an MPPT charge controller is explained in detail below. As a general rule MPPT charge controllers should be used on all higher power system with 2 or more panels, or whenever the panel voltage is much higher than the battery voltage (full explanation below). An MPPT is basically an efficient DC to DC converter used to maximise the power output of a solar panel. This technology is now used in virtually all grid-connect solar inverters and many solar charge controllers.
The functioning principle of an MPPT solar charge controller is rather simple – due to the varying degree of sunlight (irradiance) landing on a solar panel throughout the day, the panel voltage and current continuously changes. In order to generate the most power, the maximum power point tracker sweeps through the panel voltage to find the ‘sweet spot’ or the best combination of voltage and current to produce the maximum power. The MPPT is designed to continually track and adjust the voltage to generate the most power no matter what time of day or weather conditions (Note, only high-end MPPT controllers will detect partial shading, or be able to track multiple power points). Using this clever technology, the solar panel efficiency increases and the amount of energy generated is up to 30% more than a PWM solar charge controller. 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. The switch (transistor) is open until the battery reaches the absorption charge voltage. Then the switch starts to open and close rapidly (hundreds of time per second) to reduce the current and maintain a constant battery voltage. This works ok, but the problem is the solar panel voltage is pulled down to match the battery voltage. This in turn pulls the panel voltage away from its optimum operating voltage (Vmp) and reduces efficiency. PWM solar charge controllers are a great low-cost option for small systems where a single solar panel and single battery is used for simple applications.
Models Available:
| MODELS | SOLAR CHARGE CONTROLLERS |
|---|---|
| 120VDC-60A | PWM |
| 12VDC-15A | PWM |
| 12VDC-30A | PWM |
| 24VDC-15AC | PWM |
| 24VDC-30A | PWM |
| 12VDC-30A | MPPT |
| 24VDC-40A | MPPT |
| MODELS | SOLAR CHARGE CONTROLLERS |
|---|---|
| 48VDC-40A | MPPT |
| 48VDC-60A | MPPT |
| 72VDC-40A | MPPT |
| 72VDC-60A | MPPT |
| 96VDC-60A | MPPT |
| 144VDC-60A | MPPT |