Want to know how to install a MPPT Solar Charge Controller? What are MPPT Solar Controllers anyway? Find out all with our guide…
A MPPT solar charge controller is one of several types of charge regulator. Solar charge controllers are designed to ensure the control of the processes for charging and the discharge of your solar power battery bank within the solar panel powering system.
Through its control and regulatory functions, the solar charge controller will prevent the overcharging of your solar system’s battery from overcharging while also enhancing its performance.
Keep in mind that this protection is important because the 12V solar power system will produce a higher voltage of up to 20v which could be dangerous to the battery system. A high voltage above the recommended 12v could either destroy the battery or reduce its lifespan, and with some solar systems having a higher than acceptable voltage because of the use of the 24V panel that connects the 2, 12V panels connected in series, hence the need for the charge controller.
So, if you keep wondering why the MPPT solar charge controller is regarded as the most important component of the solar system, you need to keep in mind the following reasons:
- The charge controller prevents the electricity in the battery pack from getting back into the solar photovoltaic array at night.
- It protects the battery bank from being overcharged when the sun is out.
- The controller manages the extent of the power drains from your battery after you connect appliances to the generator. With the controller, high loads will be disconnected automatically, preventing extreme power discharges.
Important Components Of Battery Controllers
The controller regulates the amount of power from the photovoltaic array system directly to the battery, extending battery life. For this to happen, it features a number of important features.
- The LVD (Low-Voltage Disconnect) – This feature will disconnect the loads plugged into the battery or solar generator if it’s in a low battery charge state, while also reconnecting the appliance loads plugged when recharging your battery. This function works well in small loads, for example, in RVs.
- Reverse current protection – this function will prevent draining of the battery at night by the photovoltaic arrays when the solar panels are unable to power up and recharge your battery bank.
- Control display panel – this function of the charge controller shows then amount of power in volts in the battery, as well as the state of the charge, and the amount of current from the panels.
Types of Charge Controllers: MPPT and PWM
You have two options when it comes to these controllers – the PWM or the Pulse Width Modulation and the MPPT or the Maximum Power Point Tracking system. These controllers differ based on their operations.
But between the two, the PWMs are often used in the smaller solar panel systems while the MPPT charge controllers are ideal for use in the larger solar systems, hence their higher cost.
What Is A MPPT Charge Controller?
MPPT or Maximum Power Point Tracking is a feature that allows the input power in the MPPT to always be equal to the output power. What this means is that if the solar array’s output is 24v or 48v or higher than the voltage of the battery bank, always 12V, the MPPT charge controller will lower the power from the array to 12v.
But to do this, it compensates for the voltage drop through the increase in the current, which means that the power from the photovoltaic array to the battery is invariable.
Thanks to the fact that the MPPTs don’t lose any of the power, they offer more flexibility which allows you to connect as many panels (all in series) as possible; resulting in a significant increase in the total power/ voltage from the solar array, at no risk of losing the generated solar energy.
A MPPT solar charge controller works by squeezing out all the maximum power from your solar panel, resulting in the controller’s operation at the highest level of efficiency in terms of both the current and the voltage; hence the maximum power point. It converts the generated voltage to the optimal produced voltage, providing the highest possible charging current to your battery at all times.
Essentially, the primary role of this controller is to prevent the loss of the solar power, while maximizing the power generated from the power array. It ensures that the solar panel runs at a given voltage that’s closest to the maximum system’s power point, and it also reduces the gauge/ wire size needed for all the wires that connect the controller and the solar/ photovoltaic array.
Given their efficiency, MPPT controllers cost significantly more than the PWMs, and they are also quite efficient.
Note that the PWMs send out a series of short energy pulses to your battery rather than a steady output. In case of a battery that’s nearly charged, the pulses are short but also rarely sent, but for a discharged battery, the pulses are long, and they are sent almost constantly; hence the use of the Pulse Width Modulation in the small off-grid solar systems.
To choose the solar charge controller that best works for you, you need to consider the solar array’s current, the system’s voltage, and the type of battery.
Some MPPT Solar Charge Controller Examples
Here are some examples. Click through to Amazon for more info and/or check prices:
Setting Up A MPPT Charge Controller – Getting the Right Size Of MPPT
Most of the common solar charge regulators will have an output voltage that ranges from 12v, 24v, or even 48v, while the input voltage plus the readings of the current starts from 60v up to 60A.
With the MPPT solar charge controller, you could boost the input range to even 150v. What this means is that this controller will give you a lot more freedom to connect more solar panels, all in series, hence their use with larger solar systems.
So, how do you select and install the MPPT charge?
First, you need to find out the total installed power WP for your solar array.
Next, you need to determine the charge current IC, and you can do that by dividing the WP by the system’s voltage (12v for the off-grid panels).
Next up, you need to determine the maximum charge current (IcMax) – divide the IC by 1.2, which is the NEC safety factor.
Determine the nominal voltage for your solar array – Vmp_array. Here, you need to determine the number of solar panels connected in series. The Vmp_array is determined by multiplying the total voltage of each panel, Vmp_panel x Number of panels in series. Keep in mind that for your controller to handle the entire solar array, the value of Vmp_array must be within the input voltage range for the charge controller.
Next, check the max voltage of your solar array Voc_array, making sure that the number isn’t more than the maximum input voltage for the controller. For the Voc_array, you multiply the open circuit’s voltage of each solar panel x number of solar panels in series.
Note that the MPPT tracking efficiency goes as high as 99, while the power generation’s efficiency of your entire photovoltaic system will reach 97%.
The MPPT Setup
- Before the connection/ wiring, you first need to remove the cover then loosen the connection lock. Opening it up gives you a view of the wiring terminals for the battery, the solar panel, Load, temperature sensors, and the Rs 485 port-specific for PC.
- Now, connect the batteries to the MPPT charge controllers.
The negative and the positive terminals must be connected properly, and the batteries all connected in series. Disconnect the circuit breaker to connect the batteries.
Connect the DC load to the MPPT solar charge controller
Note that the DC load terminal for the charge controller can be easily connected to the DC load if they have the same rating for the batteries. The controller gives the power that’s based on the battery voltage.
Connecting the PV Panel Module to the charge controller
Here, you need to keep in mind that the MPPT regulator is ideal for 12V, 24V, or 48V, solar panels for the off-grid module that’s applied to the grid-tie module with which the open voltage will not exceed the maximum specified input voltage. And also, the PV module for your solar power system can’t be more than the system voltage. To connect the PV module, disconnect the circuit breaker.
The connection for the Temperature sensor/ MPPT Controller/ and the PC connection
You can only connect the controller to the temperature sensor and the photovoltaic cells via the Rs485. The Rs485 communication line is, however, optional.
Installing the MPPT Charge Controller
Besides the wiring requirements specified above, you also need to keep the following conditions in mind:
You can only install the control on a solid surface, and the installation site must be accessible at all times, and also easy to disassemble.
The ambient working environment for the controller is between -20 and 50 degrees Celsius.
Maintain a safety clearance of 20cm on the sides and 30cm upwards and at the bottom between the controller and surrounding objects for proper cooling.
The MPPT solar charge controller is one of the most important components of the large solar systems as it ensures the protection of the battery from damage and overcharging by controlling and leveling the output current.
It quite efficient, and though expensive, it’s the best investment if you are planning to use solar energy to power your home and where you plan to use many solar panels. Just make sure you follow the installation steps above correctly.