Here’s what you should know if you’re thinking Is PWM a good charge controller and whether you need a PWM solar charge controller or not? Well, a solar charge controller is required for every solar panel installation. The total system, however, determines whether a solar inverter with an integrated charge controller or an external charge controller is required. Hence let’s dive into details and see what is PWM charge controller and know many things about it.
What is PWM Charge Controller?
A PWM (Pulse Width Modulation) controller is a digital link between the solar panels and the batteries. The solar charge controller (also known as the regulator) functions similarly to a regular battery charger in that it manages the current flowing from the solar panel to the battery bank to prevent overcharging. It can accommodate several types of batteries, much like a regular battery charger.
The absorption voltage can control the float voltage as well as the time and tail current. They are most suited for lithium-iron-phosphate batteries because, after fully charged, the controller remains at the fixed float or maintains a voltage of around 13.6V (3.4V per cell) for the rest of the day.
The most common charging profile is the same straightforward sequence seen on a good mains adapter: Bulk mode – Absorption mode – Float mode.
If the battery voltage drops below the specified voltage for a longer period of time, such as 5 seconds (re-entry), this re-entry into bulk mode works better for lead-acid batteries because the voltage drop and drop are greater than for lithium-based batteries, which retain a higher, more stable voltage for the remainder of the discharge period.
In PWM solar charge controller:
1. While the charger mode is in bulk charging mode, the switch is turned On.
2. The switch is turned On and Off as needed (pulse width modulated) to maintain the absorption’s battery voltage.
3. When the battery voltage drops to the float voltage at the conclusion of absorption, it turns Off.
4. To keep the battery voltage at the float voltage, the switch is turned On and Off as needed (pulse width modulated).
5. When the switch is turned Off, the panel voltage is at the open-circuit value (Voc). When the button is pressed, the voltage is equal to the battery voltage plus the voltage difference between the board and the controller. After this, let’s learn the PWM charge controller working principle.
What is PWM Charge Controller Working Principle?
PWM solar charge controllers are the most common form of charge controller seen in solar shops. They are less expensive and simpler than MPPT controllers. PWM controllers reduce the amount of power going into your battery gradually as it nears capacity.
Your solar panel system and home battery must have matching voltages when using a PWM controller. The basic PWM charge controller working principle is that it efficiently prevents overcharging and makes full use of solar energy to charge the battery, a pulse width modulation (PWM) charge controller has been developed in recent years.
PWM charge controller to pulse mode switch PV module input, when the battery tends to be full, the frequency of the pulse or duty cycle changes, so that the on time is shortened, and the charging current gradually goes to zero.
As the battery voltage reaches its lowest point, the charging current will gradually increase again. This charging technique can extend the total cycle life of the battery in the photovoltaic system by producing a more complete state of charge. The charging state is protected by pulse width modulation, which can extend the total cycle life of the battery in a solar system. Now, let’s explore the advantages of PWM charge controller and disadvantages of PWM charge controller.
Also See: Understanding Off Grid Solar System Working Principle
What are Advantages of PWM Charge Controller and Disadvantages of PWM Charge Controller?
The advantages of PWM charge controller and disadvantages of PWM charge controller are as follows:
- At demodulation, a signal may be easily separated, and noise can also be easily separated.
- High capacity for power handling.
- Can use extremely high frequency.
- Noise interference is reduced because there is less heat generated while operating.
- When used to convert the voltage or to power a light bulb, it consumes very little energy. All three types of systems have moderate inefficiency.
- Unlike pulse position modulation, no synchronization between the transmitter and receiver is necessary.
- The system necessitates the use of a semiconductor device with short turn-on and turn-off timings. So, the cost to get one is rather expensive.
- The circuit is complex.
- Interference with radiofrequency signals.
- Communication requires a huge bandwidth.
- Due to the high PWM frequency, there is a large switching loss.
- The transmitter’s instantaneous power varies.
Also Read: 3 Amorphous Solar Panels Advantages and Disadvantages
What are PWM Solar Charge Controller Settings?
A solar charge controller can manage a wide range of battery voltages, from 12 volts to 72 volts. But, the most expensive ones can manage up to 72 volts, which is required if you intend to store your energy for an extended period of time. While solar panels can be connected in parallel to give maximum output voltage, a simple charge controller may only accept 12 or 24 volts as input voltage.
To use a solar charge controller, the voltage and current settings must be specified. You can accomplish this by altering the charge controller’s voltage setting. The voltage setting controls how quickly your solar cells recharge. These parameters can be changed using Computer software or on your charging controller. To get the most out of your solar energy system, it is advised that you follow the manufacturer’s guidelines. Otherwise, your system will fail to reach its full potential.
- Correctly connect the solar charge controller to the battery bank and panels.
- If power is detected, the controller screen will illuminate.
- Hold down the Menu button for a few seconds to access the settings menu.
- The charge current will be displayed (PV to Battery).
- Long press the Menu Button to access the Batter Type Selection menu.
- The controller will automatically detect the battery voltage.
- According to the battery user manual, set the float charge voltage, absorption charge voltage, low voltage cut-off value, and low voltage recovery value.
- Set the discharge value for the DC load (if present), and the charge controller will begin the installation process.
Also See: Solar Charge Controller Settings
Is PWM a Good Charge Controller?
After learning about PWM solar charge controller settings, let’s check if PWM is a good charge controller or not. Charge controllers are unnecessary for the vast majority of solar buyers. Rooftop or ground-mount solar installations with a battery backup are virtually always linked to the electric grid, and if your battery is fully charged, your excess solar energy will be rerouted there automatically.
If you want to establish a small off-grid solar energy system with battery backup, you should consider getting a charge controller to ensure that your battery is properly charged. A PWM charge controller should suffice for relatively small batteries paired with low-output solar panels. An MPPT charge controller may be appropriate for more complex DIY solar projects with higher output panels.
Pulse Width Modulation is widely employed in off-grid solar solutions for homes and businesses. PWM necessitates matching the voltage of the panel array to the voltage of the battery bank. Otherwise, the charging power would be lost. And the greater the mismatch, the greater the power loss. As a result, PWM is less expensive but has less flexibility and efficiency.
Recommended: How Does Solar Energy Impact the Environment?