Solar Charge Controllers for Sale
In modern solar power plants, different circuits for connecting current sources are used to transfer generated electricity to working batteries. They use different algorithms, are created on the basis of microprocessor technologies and are called charge controllers.
Solar charge controllers regulate the flow of electricity from the solar panels to the batteries. They prevent batteries from overcharging during the day when the solar panels produce more energy than the battery can hold, and also protect against reverse discharge at night.
Why Is It Necessary to Use Solar Controllers?
Solar controllers are an important link in the control chain of a solar energy system, and their functions ensure optimal operation and protection of all the equipment.
Charge Regulation
The most basic function of solar controllers is to regulate the electrical current flowing from the solar panels to the batteries. Without a controller, solar panels can transfer more energy than the battery can accept, causing it to overcharge. Overcharging can seriously damage the battery and shorten its life.
Reverse Discharge Prevention
At night, when the solar panels are not producing energy, electricity can begin to flow in the opposite direction, from the battery back to the panels, causing the battery to drain. Solar controllers prevent this reverse flow of energy.
Performance Optimization
This is especially true for MPPT controllers, which can regulate the input voltage from solar panels to maximize battery charge in all weather conditions. They allow the system to operate at peak efficiency, which is especially useful in areas with variable weather or during different seasons.
The internal safety mechanisms of solar controllers help prevent potentially dangerous situations such as overload or short circuit. This provides additional security for your solar energy system.
Energy Saving
In some systems, solar controllers also manage the energy output for loads, preventing unnecessary energy use and extending battery life.
How Solar Charge Controllers Work
The electricity generated by the solar battery can be transferred to storage batteries as follows:
- directly, without the use of switching devices and control devices,
- via the controller.
In the first method, electric current from the source will go to the batteries and begin to increase the voltage at their terminals. Initially, it will reach a certain limiting value, depending on the design (type) of the battery and the ambient temperature. Then it will overcome the recommended level.
At the initial stage of charging, the circuit works normally. But then extremely undesirable processes begin: the continued flow of charging current causes an increase in voltage above the permissible values (about 14 V), overcharging occurs with a sharp increase in the temperature of the electrolyte, leading to its boiling with an intense release of distilled water vapor from the elements. Sometimes until the containers dry out completely. Naturally, the battery life is sharply reduced.
Therefore, the problem of limiting the charging current is solved by controllers or manually. The last method, in which it would be necessary to constantly monitor the voltage value using instruments and switch switches by hand, is so thankless that it exists only in theory.
The operating algorithms of solar charge controllers depend on the type of electrical system equipment.
PWM and MPPT controllers are used to charge batteries from solar panels.
PWM Controllers
They act as switches connecting the solar panel to the battery. As a result, the voltage of the solar panels is reduced to a level close to the voltage of the battery.
These controllers are an older, simpler solution for managing battery charge in solar systems. They work by regulating the charge current, allowing a full charge of current to flow when the battery's charge level is below a set threshold, and stopping it as the battery approaches full charge. During the charging process, they switch to a "maintenance" or "trickle charge" state when the battery reaches a certain charge level, providing a small amount of current to maintain that level.
PWM controllers are a cheaper solution and are suitable for systems with small voltage differences between solar panels and batteries. They are suitable for small systems where high efficiency is not required, for example, in small home or country installations.
PWM controllers, in turn, come in two types: shunt and serial.
Shunt PWM controllers
These work by creating a "bypass" or "shunt" path for electrical current when the battery reaches its maximum capacity. This prevents the battery from overcharging by redirecting excess energy. Shunt controllers are usually easy to use and inexpensive, but they can be inefficient because they do not use excess energy.
Serial PWM controllers
Series controllers, unlike shunt controllers, interrupt the flow of energy from the solar panels to the battery when it is fully charged. They do this by “disabling” the solar panel. Series controllers are generally more efficient than shunt controllers because they prevent energy loss through the shunt. However, they can be more difficult to install and maintain.
The choice between shunt and series controllers largely depends on the specification of your solar power plant and personal preference. In both cases, the key function of the controller is to protect the batteries from overcharging, which extends their service life and improves the efficiency of the system as a whole.
PWM controllers can additionally:
- take into account the temperature of the electrolyte using a built-in or remote sensor (the latter method is more accurate);
- create temperature compensation for charging voltages;
- configured for a specific type of battery (GEL, AGM, liquid acid) with different voltage graphs at the same points.
MPPT Solar Controllers
This maximum power point tracking regulator is an advanced version of the pulse width modulation shunt regulator.
MPPT controller is a more complex and expensive device. To charge the batteries and power the load, it adjusts its input voltage to extract maximum power from the solar panel. The controller changes the output voltage depending on the condition of the battery. The voltages at the input and output of the MPPT controller are independent of each other. A 12-volt battery can be connected to its output, and series-connected solar panels with a voltage of 36 V can be connected to the input.
MPPT controller is more effective than PWM in cold and temperate climates. In subtropical and tropical climates, both devices show approximately the same performance.
Solar panels will quickly charge batteries if the controller is able to select a point on the panel’s current-voltage characteristic that corresponds to its maximum power. Only the MPPT controller does this. The input voltage of the PWM controller is equal to the voltage of the battery connected to its output, plus the voltage loss in the cable and in the controller itself. With a PWM controller, the solar panel in most cases does not deliver maximum power.
In complex MPPT regulators, the microcontroller controls the battery voltage, its charge level and the output current of the solar panel. Based on this data, the regulator sets the panel's output voltage so that its output is maximized under that particular set of conditions. A control circuit in the DC/DC converter is used to achieve the desired result.
For example, for 12 V solar panels, the maximum power output point is about 17.5 V. An ordinary PWM controller will stop charging the battery when the voltage reaches 14-14.5 V, and one operating using MPPT technology will allow additional use of the solar battery resource up to 17.5 V.
As the depth of battery discharge increases, energy losses from the source increase. MPPT controllers reduce them.
In this way, MPPT controllers, using pulse-width conversions in all battery charging cycles, increase the output of the solar battery. Depending on various factors, savings can be 10-30%. In this case, the output current from the battery will exceed the input current from the solar battery.
Choosing the Optimal Charge Model Controllers
When choosing a controller for a solar battery, in addition to knowing the principles of its operation, you should pay attention to the conditions for which it is designed.
The main indicators of these devices are:
- input voltage value;
- the value of the total solar energy power;
- nature of the connected load.
The controller can be supplied with voltage from one or more solar panels connected in different circuits. For proper operation of the device, it is important that the total voltage supplied to it, taking into account the no-load source, does not exceed the limit value specified by the manufacturer in the technical documentation.
topRik marketplace gives you the opportunity to pick up charge controllers that will exactly match your yacht's solar power plant. We present the products of one of the world's best manufacturers of autonomous power plants and systems for boats, including the production of Victron Energy company. The range includes charge controllers type PWM and MPPT of the following modifications:
- BlueSolar PWM - simple and inexpensive devices for charging batteries from photovoltaic modules, which have protection against overheating, overload, short circuit and reverse polarity;
- BlueSolar MPPT - lowers the output voltage to the level necessary to charge the batteries, proportionally increasing the current and retaining almost all the power produced by the solar modules;
- SmartSolar MPPT – additionally equipped with a built-in Bluetooth module, which allows you to connect the controller to a smartphone without using a special cable;
- SmartSolar MPPT RS – ideal for large off-grid and grid-connected battery systems.
Charge controllers such as PWM and MPPT are accompanied by appropriate accessories for them. If necessary, you can buy an optional MPPT Control display for monitoring, panels, USB cables, temperature sensor, etc.
topRik experts are ready to provide professional advice free of charge on all arising issues.