Solar charge controllers

What is a solar charge controller

The solar charge regulators are installed between the photovoltaic modules and the battery to control the state of charge of the battery itself. For voltages of 12V and 24V it is necessary to have a solar charge controller to control the charge and discharge of the battery or accumulator that we have in the photovoltaic installation. In FVComponentes.com we have two types of charge controllers: mppt solar charge controller and pwm controller.

Charge controller models

A charge regulator is a device that regulates the amount of energy stored in the batteries. It can work independently or integrated in an inverter. A mppt solar charge controller or pwm solar charge controller controls and protects the batteries in a photovoltaic system, prevents overcharging and over-discharging, and ensures efficient use of energy.

pwm charge controller

This solar charge regulator only acts as a power cut-off between the solar panels and the batteries when it has a full charge. For this victron charge regulator to work properly, the solar panels and the batteries of the photovoltaic installation must have the same voltage.

mppt charge controller

This mppt solar charge regulator cuts the current flow of the photovoltaic modules when the battery is fully charged. In addition, an mppt solar charge regulator is able to adapt the output voltage of the photovoltaic module to the battery voltage; so we can have in the same system, for example, 12V solar panels and 24V battery.

MPPT charge controllers have three very important limitations to consider when choosing the solar charge controller we need.

The first limitation that we find in a 12v solar charge regulator, or any other voltage, is the maximum power of the photovoltaic field. Each photovoltaic regulator will limit the amount of W that all the photovoltaic panels we have in our system add up to. For example, if we have 2 solar panels of 150W, we must take into account that we have 300W of photovoltaic field. photovoltaic field.

The second limitation of a mppt 24v solar charge regulator is that we must never exceed the maximum amps of the solar panel regulator. To calculate the amperes of the regulator that come down from the photovoltaic is obtained by the sum of all the solar panels.

If 2 or 3 PV arrays are made, the voltage of the regulator and not the amperage of the regulator must be added, so the amperage drop of a group of 2 PV arrays will be the same as if there were one panel, but at twice the voltage of the regulator.

The last limitation of an mppt regulator is its input voltage. Typically, an mppt has a higher input voltage than a pwm solar charge controller, so it allows us to have several PV panels in series.

Price of a solar charge controller

As a general rule, a pwm regulator is cheaper than an mppt regulator. The difference between mppt and pwm regulators is the one mentioned in the previous section, that the mppt regulator is able to adapt the voltage, so it is not necessary for the panels and batteries of a photovoltaic installation to operate at the same voltage.

mppt solar charge controllers range from €40 to almost €2000, while a pwm solar controller is priced from €16-70. The higher the capacity to handle higher currents, the higher the price of the regulator.

Buy a mppt controller or a pwm solar regulator

The following aspects should be taken into account when buying a new car solar charge controller:

• Controller type: PWM for smaller systems and limited budgets. MPPT, perfect for larger systems that need more efficiency.
• Current capacity (Amperage) of the regulator: Select a regulator that can handle the maximum current generated by your solar panels. It is best to choose one with a higher capacity to avoid overloading.
• Compatibility of the mppt or pwm controller with the system voltage: The solar charge controller must be compatible with the system voltage (12V, 24V, 48V) and with the type of batteries in the installation.
• Battery type supported: The solar charge controller must be compatible with the type of battery you have. It should have adjustable settings for proper charging.
• Solar controller efficiency and performance: Consider the efficiency of the solar charge controller, especially if you are looking to maximise energy conversion in low irradiation conditions.
• Extras: A dimmer can include additional features such as LED or LCD displays, as well as overload protection, remote monitoring or lighting control.

Uses of victron charge controllers

A solar charge controller is an essential part of any solar photovoltaic system. The 5. charge regulator is placed between the photovoltaic panels and the battery and is responsible for controlling the voltage and intensity with which the batteries are charged. A 12v battery charge regulator, or any other voltage, is an essential part as it takes care of and extends the life of the battery.

The mppt or pwm charge controller also protects the batteries against overcharging or deep discharging. Thanks to the pwm or mppt solar charge controller, the battery status is monitored at all times.

mppt and pwm are very useful components in remote PV systems. A solar charge regulator is one of the essential elements in off-grid photovoltaic installations. In these installations, the proper functioning of the batteries is very important and, for this purpose, the work of solar charge controllers is crucial. Victron charge controllers are also essential in other types of kits, such as those for camper vans.

The following picture shows a solar charge controller scheme:

There are many models of mppt, if you need to calculate mppt solar controller for your installation, you can use this one victron mppt calculator. This tool will help you find the mppt solar charge controller that best suits your needs. The most common mppt solar models are: victron mppt 100/30, mppt 75/15 and victron mppt 100/50. At FVComponentes.com we have all models of victron mppt.

If you've visited the victron mppt controller calculator website, you already have the answer to the question "which solar charge controller do I need?", but you may be wondering how to connect a solar charge controller; in the following section we will answer this question.

How to connect a charge controller

It is very important to take into account the cable cross-sections in photovoltaic systems. In the case of direct current at low voltages, the charge regulator cable must have a larger cross-section than in alternating current installations, as in installations in homes for regular consumption.

If you are wondering how to calculate the cross-section of a cable for the installation of a solar regulator, in our blog we have a post that explains it in detail. The cable section we need varies depending on whether it is a mppt or pwm regulator. For example, if we have a 12v pwm regulator, the cable section must be the same from the solar panels to the solar regulator and the battery; but if we have a mppt solar regulator, the cable section must be calculated according to the voltage of the solar panels and the battery, as in this case it may vary.

This is one of the great advantages of MPPT solar regulators. By having higher voltages in the photovoltaic field we can reduce the section of the photovoltaic wiring, with a larger section in the wiring between the charge controller and the accumulators, because MPPT will reduce the voltage of the field to the operating voltage.

Solar charge controller

mppt or pwm solar charge controllers automatically adapt to the different battery conditions. The solar charge controller can also be used to manually adjust certain parameters.

If you are wondering what an mppt is, it is a solar regulator that allows you to connect panels and batteries of different voltages. On the other hand, a pwm regulator works in a different way, the solar panels and the battery of the photovoltaic installation must have the same voltage to be able to use this type of charge regulator.

PWM solar photovoltaic regulators are simpler, they work on battery voltage. They are said to act as "switches" for the solar panels. An mppt has a maximum power follower and works at the voltage that best suits the battery, depending on the moment. An mppt regulator is the one that gets the most out of the photovoltaic modules.

How a solar charge controller works

These regulators are specific to photovoltaics and are responsible for limiting the charge and discharge limits. When a battery is charged to 100%, the regulator cuts off the electricity from the solar panels to the battery. When the consumption is greater than the load on the battery, and reaches the limit of its capacity, the pwm or mppt regulator intervenes to cut the consumption that we are doing, preventing the complete discharge of the battery. What a solar charge regulator does is to control the charging and discharging of the battery.

Photovoltaic regulators are composed of two inputs and one output for consumption. Each solar charge regulator has an input for the positive and negative of the photovoltaic panels and an output for direct consumption at 12V. If our system works at 12V we only need the solar panel, the battery, and the solar charge regulator, in addition to having a 12V consumption.

Manual solar controller

If you are wondering how an mppt or pwm regulator works, this is the section you are looking for.

A photovoltaic regulator is an element that controls the amount of energy that reaches the batteries in a photovoltaic system. The photovoltaic charge regulator allows you to optimise the installation of solar panels and extend their service life.

A solar controller is very easy to configure, provided that you use the mppt manual in English. Following the instructions of the solar controller manufacturer, you follow these steps to configure the device:

1. Connect the positive and negative cables from the storage tank to the solar controller.
2. Determine the maximum voltage at which the PV module should charge the battery.
3. Set the reconnection voltage on the charge regulator to indicate the limit for reusing the battery.
4. Limit the disconnection voltage of the PV charge controller to protect the batteries from over-discharging.
5. Mark the number of hours the battery will be in use.
6. Check the compatibility between the solar controller and the battery.

Once the photovoltaic controller has been configured, several problems can occur. Although they are not very important, it is necessary to be aware of them so that if they occur with our photovoltaic charge controller we are prepared.

The most common problems with this installation start with the batteries, which may not charge or may be overcharged. Another problem that can arise with an mppt or pwm charge controller is that the reverse PV current is too high.

It may happen that less power is generated than expected and this affects the pwm or mppt regulator. On the other hand, we may have made the general connections to the charge controller incorrectly.

Steps to follow to check the status of the system:

• Override the solar regulator
• Connect the cables of the PV modules directly to the batteries and check their status.
• It measures the current flowing from the solar panels to the accumulators.

If all these steps work correctly, the problem is with the mppt or pwm, so you should check your connections.

Advantages of using a solar charge controller

• Battery protection: Avoids overcharging and over-discharging, prolonging the life of the accumulators.
• Monitoring and control: Provides real-time information on system status for easier management.
• System stability: Maintains voltage and current at safe levels, protecting the entire system.
• Prevents damage due to short circuits, overheating and reverse polarity.
• Energy optimisation: Ensures that energy is being used efficiently, especially in MPPT controllers.

Maintenance and cleaning of solar charge controllers

Maintenance of the charge controller is essential to ensure efficient operation and prolong its service life.

• Cleaning: Make sure it is clean and free of dust, dirt and moisture. Wipe the outside of the appliance with a dry cloth.
• Check connections: Check that all connections are tight and free of corrosion.
• LED monitoring: Make sure the lights indicate that the device is working properly. If the display shows any alerts or error codes, refer to the mppt manual.
• Checking the input voltage: Use a multimeter to measure the voltage coming into the device from the solar panels. Make sure it is within the manufacturer's parameters.
• Check the output voltage: check that the values are as indicated by the manufacturer and suitable for your battery.
• State of charge: Check that you are charging the battery correctly by ensuring the charge level with a multimeter or monitoring system.
• Battery inspection: Make sure that the battery is not oversized or over-discharged, as this may damage the battery or charge controller.
• Temperature check: Check if it is operating within the recommended temperatures. Avoid getting too hot, this could be a problem.
• It should be installed in a well ventilated location to avoid overheating.
• If damaged or malfunctioning components are detected, they must be replaced immediately to avoid major failures.