Making a controller for a solar panel

Imagine using the sun’s energy to power and heat your house while lowering your carbon footprint and energy costs. A growing number of homeowners are looking at solar panels as a practical solution as awareness of sustainable living grows. However, close observation and management are necessary to maximize the efficiency of these panels. In order to guarantee optimal performance, a solar panel controller steps in as the operation’s brain.

Fundamentally, a solar panel controller acts as a bridge between your home’s solar panels, batteries, and appliances. It controls the flow of electricity, making sure that the energy produced by the panels is effectively stored and used. Imagine it like the conductor of an orchestra, arranging all the instruments to create a harmonious whole.

Overseeing the battery charging process is one of a solar panel controller’s primary duties. Overcharging or undercharging can seriously shorten battery life and negatively impact performance if improper regulation is not in place. The controller makes sure that the batteries receive the best possible charging rate, extending their lifespan and maximizing their capacity, by closely monitoring the voltage and current levels.

Additionally, a solar panel controller is essential for safeguarding your system against possible harm brought on by variations in voltage and current. Power spikes or surges can seriously damage delicate electronic components, necessitating expensive replacements or repairs. The controller acts as a safety net, protecting your investment from damage and giving you peace of mind thanks to built-in protection mechanisms.

Perhaps most importantly, though, is that a solar panel controller gives you the ability to manage both your energy production and consumption. You can track the performance of your solar panels in real-time, spot any problems or inefficiencies, and make well-informed decisions to optimize your system with features like data logging and remote monitoring. A solar panel controller gives you control over your energy use, whether your goal is to lower your carbon footprint or just save money on utility bills.

Varieties

Charge controllers come in a variety of varieties these days. Think about a few of them.

MPPT controller

This abbreviation stands for Maximum Power Point Tracking, i.e. monitoring or tracking the point where the power is maximized. Such devices are capable of reduce the voltage of the solar panel to battery voltage. With this arrangement, the current strength of the solar panel decreases, as a result of which it is possible to reduce the cross-section of wires and reduce the cost of construction. Also, using this controller allows you to charge the battery when there is not enough sunlight, such as in bad weather or in the early morning and evening. It is the most common because of its versatility. Used in series connection. MPPT-controller has a fairly wide range of settings, thanks to which the most efficient charging is ensured.

• The cost of such devices is high, but it pays off when using solar panels over 1000W.
• The input total voltage to the controller can be up to 200 V, which means that several solar panels can be connected in series to the controller, up to 5 on average. In cloudy weather, the total voltage of series-connected panels remains high, thus ensuring uninterrupted power supply.
• This controller can work with non-standard voltage, for example, 28V.
• MPPT-controller efficiency reaches 98%, which means that almost all solar energy is converted into electrical energy.
• Ability to connect different types of batteries such as lead, lithium-iron-phosphate and others.
• The maximum charging current is 100 A, at this current value the maximum power output of the controller can reach 11 kW.
• Basically all models of MPPT controllers are able to operate at temperatures ranging from -40 to 60 degrees Celsius.
• It requires a minimum voltage of 5V to start charging the battery.
• Some models have the ability to simultaneously work with a hybrid inverter.

These controllers are suitable for use in both commercial settings and residential settings because they come in various models with varying indicators. An MPPT controller with a maximum power of 3.2 kW and a maximum input voltage of 100 V is appropriate for a rural home. Much more potent controllers are used for higher volumes.

PWM controller

Compared to the MPPT, this device has simpler technology. The way such a device works is that the solar panel is connected to the battery almost directly when the voltage is below the 14.4 V limit, allowing for a quick charge. Once the value is reached, the controller lowers the battery voltage to 13.7 V, which causes the battery to be fully charged.

• Input voltage not exceeding 140 V.
• Work with 12 and 24 V solar panels.
• Efficiency is almost 100%.
• Ability to work with multiple batteries of different types.
• The maximum value of current input reaches 60 A.
• Operating temperature from -25 to 55 degrees Celsius.
• Ability to charge the battery from scratch.

Therefore, when solar energy is sufficient and the load is not very large, PWM controllers are most frequently used. Owners of modest country homes with modestly sized solar panels installed would benefit more from such devices.

As previously mentioned, the MPPT-controller is currently the most widely used due to its high efficiency and ability to function even in low-light conditions. Large country homes would benefit greatly from the MPPT-controller’sabilityto run at higher power. Nevertheless, you must consider the degree of power and voltage indicators, input and output current, and other factors before selecting a specific type.

Selecting a controller that doesn’t fit the specifications will, at best, cause it to malfunction; at worst, it may damage the home’s wiring.

It is inefficient to install an MPPT controller on a small plot because it will not yield any benefits. The MPPT controller ought to be utilized if the solar panel’s overall voltage exceeds 140V. PWM controllers are the least expensive; their starting price is 800 rubles. There are models priced at 10,000 rubles, which roughly equates to the cost of an MPPT-controller.

How to make a battery charge controller with your own hands

Following the purchase of photovoltaic cells and the construction of a solar panel or homemade wind generator, the issue of what to do with extra energy arises when the battery is fully charged and the wind generator or panel keeps producing energy. This has potentially disastrous effects on the energy sources and the battery itself. The wind wheel can become uncontrollably fast and even explode due to overcharging, which also damages the battery’s plates.

This will enable us to create a straightforward yet dependable universal charge controller that can be used to recharge batteries from wind turbines and solar cells alike. Michael Davis created the unit’s initial circuit design.

A relay driven by a threshold circuit with a field-effect transistor key switches the signal from the rectifier of a wind generator or solar panel. Trim resistors are used to regulate mode switching thresholds. The author employed eight resistors (heating elements) with a resistance of 4 Ohm and a dissipation power of 50W as a load to maximize energy utilization at full battery charge. A plastic case was used in the design of the final product.

I purposely avoided drawing your attention to the project’s detailed description because the author quickly started working to refine and streamline the design of his creation. updated and streamlined controller design, which I suggest carefully reviewing. The circuit diagram shows that the author used eight resistors, or heating elements, with a dissipation power of 50 W. Despite this change, the device’s basic operating principle remains the same.

The circuit itself has been simplified; the author used the most widely used timer chip, the NE555P, in place of OU and logic chips. Let’s talk more about the project’s component selection in detail.

A widely used integrated stabilizer 7805 (K142EN5A) is used to stabilize the circuit’s supply voltage. NTE123, 2N3904, or any other bipolar NPN structure with the right parameters can be used in place of transistor Q1. The field-effect transistor IRF540 is no different—anyone with the right specs can replace it. Utilizing multi-turn resistors is preferable.

Any of them with a 0 to 100K adjustment interval will work; however, the adjustment will be much more accurate if you use 10K resistors, which is important when determining the charging modes for gel batteries.

A 12V automotive relay with the ability to switch currents of 30-40A is used as a switch. Capacitors of the stabilizer trim can be put any – from ceramic to film, although I, as a reinsurer, would put the film. The LEDs in the charge controller can be of any color – LED1 induces the mode of "resetting" the energy to the load, and LED2 – the battery charging mode. Buttons PB1 and PB2 are any reliable, without fixation, they are used for switching the circuit "manually" during adjustment (measuring voltage in test points TP1 and TP2). During the initial adjustment of the circuit, the voltage in the control point TP1 is set equal to 1.667V, and in the control point TP1 the voltage in the control point TP1 is set equal to 1.667V.667V, and in the control point TP2 – 3,333V. It is desirable to provide all power supply circuits of the device with fuses for appropriate currents.

After assembling the gadget on a circuit board, the author placed it inside a case that was the right size.

But one of his resourceful coworkers, Jason Markham, created a printed circuit board for the controller and started selling a self-manufacturing kit (38 dollars) and the completed product (54.95 dollars) online.

America, there is nothing that can be done, even though our home builder will put together a dozen of these battery charge controllers for that kind of money.

Long-term tests of the controller with solar panels and wind turbines have demonstrated its high reliability.

Lastly, a brief note: turn on the system’s controller only after the battery has been inserted into its contacts. If not, the device might malfunction or not function at all. Electrodych is the article’s author.

How to construct a battery charge controller by hand How to construct a battery charge controller by hand Following your purchase of photovoltaic cells and construction of a solar panel or DIY wind generator, the following query comes up:

Structural diagrams of controllers

PWM and MPPT controller circuit diagrams are too intricate for the average person to understand without a thorough understanding of electronics. It makes sense to focus solely on the structural diagrams as a result. The general public can understand this approach.

Option #1: PWM devices

A resistive circuit that separates and stabilizes the element is fed by the voltage that the solar panel produces on two conductors (plus and minus). In addition to organizing the controller input protection from going over the input voltage limit, this circuitry is used to equalize the input voltage potentials.

It is important to note that each device model has a different input voltage limit that is indicated in the documentation.

This is a general representation of the PWM-based devices’ structural diagram. This circuit approach offers quite sufficient efficiency for use in a small household station. (+)

Power transistors also limit the voltage and current to the necessary amount. The driver chip allows the controller chip to control these circuit components in turn. Consequently, the battery’s typical voltage and current are determined by the output of two power transistors.

A temperature sensor and a driver that manages the power transistor, which controls the load power (protection against deep discharge of the battery), are also included in the circuit. Crucial PWM controller elements’ heating condition is tracked by a temperature sensor. Usually the temperature within the housing or on the power transistor heatsinks. The gadget disconnects all active power lines if the temperature rises above the parameters.

Option #2: MPPT devices

The scheme’s complexity in this instance stems from the addition of several components that meticulously construct the required control algorithm based on the operational parameters. Comparator circuits monitor and compare voltage and current levels, and the comparison’s outcome determines the maximum output power.

Charge controller schematic solution in structural form based on MPPT technologies. A more intricate algorithm for the monitoring and management of peripheral devices has already been noted here.

This kind of controller can adjust the solar module for maximum power regardless of the weather, which is the primary distinction between it and PWM devices. Several control methods are implemented by these devices’ circuitry:

• perturbation and observation;
• increasing conductivity;
• current sweep technology;
• constant voltage.

Additionally, a different algorithm that compares all of these techniques is used in the last section of the general action.

Types

On/Off

This kind of gadget is thought to be the most basic and affordable. Its sole and primary function is to stop the battery from charging when the maximum voltage is reached in order to avoid overheating.

This type does have one drawback, though: it disconnects too soon. The charging process must be continued for a few more hours after the maximum current is reached, at which point the controller will turn it off right away.

Consequently, approximately 70% of the maximum current will be used to charge the battery. The battery is negatively impacted by this.

PWM

This kind is a sophisticated On/Off. Its integration of a pulse width modulation (PWM) system is what makes it modern. Instead of cutting off the current supply when the maximum voltage is reached, this feature enables the controller to decrease the current supply.

This has made it possible to charge the device nearly 100% of the time now.

MRRT

This kind is thought to be the most sophisticated kind that is currently offered. Its ability to precisely calculate the maximum voltage for a particular battery forms the basis of its operation. It keeps an eye on the system’s voltage and current continuously. The CPU can generate the most power possible because it continuously acquires these parameters, which enable it to maintain the best possible current and voltage levels.

The efficiency of the MRRT controller is approximately 20–35% higher than that of the PWN controller.

When it comes to heating and insulating your home, it"s all about efficiency and comfort. Proper insulation keeps the heat inside during the winter and blocks out excessive heat during the summer, making your home cozy year-round while saving on energy bills. Meanwhile, using solar panels to harness the sun"s energy is a smart move towards sustainability and cost-effectiveness. However, to make the most of solar energy, you need a reliable controller to manage the power flow efficiently. Designing a controller for your solar panel system allows you to regulate the energy output, store excess energy, and ensure seamless integration with your home"s power grid. By combining effective insulation with a well-designed solar panel controller, you can create a home that"s both environmentally friendly and economically sound.

Principle of operation

The controller is in sleep mode when the solar panel is not producing any current. There is not even a single watt of battery usage. Electric current flows to the controller as soon as sunlight strikes the panel. It must be turned on. But only when the current voltage hits 10V will the indicator LED and two weak transistors turn on.

Current will pass through the Schottky diode and into the battery once this voltage is reached. The MOSFET transistor will open when amplifier U1 activates when the voltage reaches 14 V. Consequently, the two non-power transistors close and the LED turns off. There won’t be a battery charge. This is when C2 will be released. It requires three seconds on average. Capacitor C2’s discharge will cause the MOSFET to close, overcome U1’s hysteresis, and initiate battery charging. Up until the voltage reaches the switching level, charging will occur.

Periodically, charging takes place. In this instance, the battery’s charging current and the power of the devices attached to it will determine how long it lasts. The voltage is not released until it reaches 14 V.

In an instant, the circuit is turned on. Transistor Q3 limits the current, which in turn affects the charging time of C2 and its activation. There can be no more than 40 mA of current.

Wind turbines and battery charge controllers

Is it feasible to construct a wind turbine with just your hands and a wind turbine controller if a mechanical wind turbine can be made on your own?

It is not unnecessary to have some basic knowledge about wind turbine controllers in order to successfully replicate such a technique with your own hands.

Controller for charging batteries in a small wind turbine generator. The integrated LCD display allows for the monitoring of certain system parameters.

The main purpose of the controller, which looks after the batteries, is to control the charging process. Although it should be conditionally divided into several sub-functions, this is its primary function.

One feature, for instance, keeps track of the charge and self-discharge currents. Measurement actions related to pressure and temperature are realized by another functionality. When the load and battery are being charged simultaneously, the third is in charge of making up for the difference in energy flows.

Industrial production devices have complete functionality. On the other hand, amateur designs cannot claim this. Controllers that are constructed from scratch at home using the most basic circuit solutions are far from ideal models.

Still, they function and produce enough energy to run wind turbines. Generally speaking, deep discharge and overvoltage protection is the sole purpose of homemade constructions.

One of the numerous designs of homemade wind turbine controllers. Simple installation designs and straightforward technical solutions define these constructions.

Why is it necessary for the wind turbine system to have a controller installed? Given that the following unfavorable outcomes are typical of the battery’s energy feeding method without the use of a controller:

1. Degradation of the battery structure due to uncontrolled chemical processes.
2. Uncontrolled rise in electrolyte pressure and temperature.
3. Loss of recharging properties of the battery due to long-term discharge.

Typically, a wind turbine’s charge controller is manufactured as a separate electronic module. This module can be quickly disconnected and removed. Industrial production devices must have a means of indicating modes and states, either visually or through light transmission via a display.

In actual usage, there are two kinds of devices that can be employed: ones that are integrated into the wind generator housing and ones that are connected to the battery pack.

Main Functions

System powering it with a controller. (Toggle to make larger)

1. Selecting the optimal battery charging current.
2. Battery disconnection when the battery is charged to the set limit.

Purchasing such a controller from a specialty retailer is not required. With just a soldering iron and a basic understanding of electrical engineering, you can put together a simple circuit by yourself.

These devices come in various varieties. The most basic ones only have one purpose, which is to connect and disconnect the battery based on its level of charge.

Complex devices guarantee a higher output current by monitoring peak power, increasing system efficiency.

The specifications for each controller are as follows: 1.2P ≤ I×U, where P is the total power of the panel, I is the output current of the controller, and U is the output voltage of the load.

The simplest homemade controller

There are some requirements that you must make sure to meet when creating your own controller. First and foremost, the battery voltage at no load must match the maximum input voltage. Second, one needs to observe the ratio of 1,2P.

An illustration of the most basic controller

This unit is intended to operate as a component of a small-scale solar power plant. The controller operates on a very basic principle. The charging process is terminated when the voltage at the battery terminals reaches a predetermined level. Only a so-called drip charge is carried out after that.

A printed circuit board with a controller mounted on it

The battery supply is restarted when the voltage falls below the predetermined threshold. The controller will disconnect the load if, while the load is operating without power, the battery voltage falls below 11 volts. By doing this, the batteries are kept from draining during cloudy days.

OnOff controllers

When a specific voltage (14.4V) is reached, the device disconnects the charge, making it the most basic of the ones currently in use. By doing this, the gadget is kept from overheating and overcharging. Simultaneously, it is not feasible to guarantee a complete charge of the battery, as the battery is disconnected upon reaching the maximum current, even though the process needs to be continued for several hours. Because of this, the charge level is continuously between 60 and 70 percent, which has an impact on the plates’ condition and shortens the battery’s lifespan.

This module is actually only loosely a controller; in reality, they are more accurately described as automatic shutdown devices and are hardly in use today.

Setting up the solar panel battery charge controller

A regulated power supply unit (rather than the solar panel) should be connected to the input after the components have been mounted and any errors have been verified. A voltage of 17–20 volts should be applied initially. It is necessary to adjust resistor R19’s resistance in order to set the stabilizer’s output voltage between 13.6 and 13.8 volts. The LED D2 should then light up by selecting an input voltage of approximately 13.1 volts and using the adjustment resistor R18. The D2 LED should turn off when the power supply voltage falls below 13 volts.

The LED D3 will then turn on after the input voltage is adjusted to 15.5 volts and the adjuster R4 is turned. In order to set the charging indication, a battery is required. Use an ammeter to connect it to the controller, then adjust the power supply’s voltage to charge the battery at a rate of roughly 50 milliamperes. Next, adjust resistor R14 such that D4 illuminates. The D4 LED should go out when the current falls below 40mA. With a lead-acid battery, the controller’s own consumption (from the battery) is negligible at 9–10 mA.

Chinese electronic alternative

Creating a wind generator controller by hand is an esteemed endeavor. However, the concept of self-assembly frequently becomes obsolete due to the rapid advancement of electronic technologies. Furthermore, the majority of the suggested schemes are already out of date.

Purchasing a professionally assembled, ready-made product with superior assembly on contemporary electronic components ends up being more affordable. For instance, Aliexpress offers a reasonable price on a suitable device.

The Chinese website has an amazing selection of offers. Wind generator controllers with varying power outputs can be purchased for as little as 1000 rubles. It is obvious that the game is not worth the candles if we begin at this point in terms of physically assembling the apparatus. One of the Chinese portal’s suggestions, for instance, is a model of a 600-watt wind turbine. The item is priced at 1070 rubles. appropriate for use with batteries ranging from 12 to 24 volts in operating current mode up to 30 amps.

Very good, Chinese-designed charge controller for a 600-watt wind generator. A device of that kind can be ordered from China and shipped to the recipient in roughly one and a half months.

An effective cooling radiator is included in the 100 x 90 mm premium all-weather controller housing. The IP67 protection class is in line with the housing design. Range of external temperature: -35 to +75ºC. The wind generator status modes are indicated by a light on the housing.

If there is a genuine chance to purchase something comparable and of a higher caliber, why would you take the time and trouble to put together a basic construction yourself? In any case, the Chinese have some extremely "cool" options if this model is insufficient. As a result, one of the newest models has a 2 kW power output at 96 volts of operation.

Chinese item from the list of recent arrivals. controls battery charge when used in conjunction with a 2 kW wind generator. takes up to 96 volts as an input voltage

It’s true that this controller costs five times as much as the last one was developed. However, when we weigh the expenses of purchasing versus making something comparable by hand, the purchase appears to be a sensible choice.

The one embarrassing thing about Chinese products is their propensity to abruptly stop functioning at the most inconvenient times. For this reason, you frequently need to perfect a purchased device—of course, by hand. However, compared to building a wind generator charge controller from scratch, this is far more straightforward and easier.

What can be used to replace some components

These components can all be changed. It is important to consider altering the capacitance of capacitor C2 and choosing the bias of transistor Q3 when installing additional circuits.

Any other type of transistor can be installed in place of a MOSFET transistor. The open channel resistance of the element needs to be low. It is preferable to leave the Schottky diode in place. An ordinary diode can be installed, but it must be positioned properly.

The resistances R8, R10, and 92 kOhm are equal. This number is not typical. This makes these resistors difficult to locate. A complete substitute for them could be a pair of resistors with 82 and 10 kOhm. To be used in series, they must be changed.

You can install a trimmer resistor if the controller will not be used in an aggressive environment. It enables the voltage to be controlled. In a hostile environment, it won’t last very long.

It is required to replace the MOSFET transistor and diode with stronger analogs if using the controller for stronger panels is required. There is no need to alter any of the other parts. Installing a heatsink for 4A regulation is pointless. A MOSFET installed on an appropriate heat sink will enable the device to operate with a more efficient panel.

What are battery charge controllers for?

The battery will continuously charge if it is connected directly to the solar panel terminals. The battery is already fully charged, so eventually it will keep getting current, which raises the voltage by a few volts. Consequently, the battery becomes excessively charged, the electrolyte temperature increases, and eventually reaches a point where it boils, causing a sudden discharge of fumes from the battery containers. This could lead to the electrolyte completely evaporating and the cans drying out. Naturally, this severely shortens the battery’s service life and does not increase its "health."

In a solar battery charging system, the controller

Here, controllers are required to maximize the charge/discharge processes and stop such occurrences.

Tips

You should install the units in well-lit areas to get the most out of them.

Placing the device as high as possible is crucial at the same time.

The building’s orientation should be south. A small deviation, not to exceed 20 degrees, is permitted.

The installation of the device is done at an angle with respect to the horizon.

The most sophisticated devices have a unique electric actuator built into the design that modifies the angle in response to changes in the sun’s position.

To find out more about the nuances involved in choosing and installing a solar panel, watch the video below.

Selection by output current

When choosing a controller, matching the output current strength is just as crucial as the input voltage. The formula is used to calculate the total capacity of all batteries, which is then divided by the voltage of all the energy storage devices in the discharge stage.

Let’s look at a specific example: the system uses a 48 volt battery and a solar panel (2250 W) made up of 9 slabs, each with a 250 W capacity. The formula above states that you should divide the total power by the battery’s minimum voltage when it is discharged, or the minimum output voltage, which in this case is 44 V. You should then multiply the result by 25%. We obtain: 64 Α = 2250/44 * 25%. Therefore, for this system, controllers with an output current rating of 64 amps or higher are recommended.

The controller enables you to obtain the maximum battery charge while minimizing system loads by utilizing all of the previously mentioned selection rules.

October 15, 2014

Choosing a battery

A number of factors can influence the choice of batteries for solar panels:

• Those who have means and opportunities, purchase long-lasting and, at the same time, expensive alkaline batteries – nickel-cadmium (NC) or nickel-iron (NI) batteries.
• Someone buys specialized gel batteries made by GEL technology, which in comparison with the usual starter batteries last much longer, but also cost more expensive.
• Those who prefer the most affordable option use starter car batteries.

Given that the battery selection is primarily determined by the owner of the SB’s actual capabilities, it is exceedingly challenging to make recommendations in this area. However, it is worthwhile to enumerate the benefits and drawbacks of the different batteries.

Acid batteries for cars

For most customers, starter batteries are the most affordable and easily available type of batteries. These batteries are buffer batteries, which means that even with their impressive capacity, their initial purpose is short-term shallow discharge followed by rapid recharging to full capacity. They are not made for deep discharge or cyclic operation, though. Thus, the drawbacks of the batteries that are being offered.

Establishing circumstances where a car battery’s discharge does not surpass 20–30% of its nominal capacity is essential to maximizing its service life. The battery needs to be instantly recharged at the same time. Since it can be challenging to implement such a cycle in autonomous power supply systems, the battery is typically only partially discharged—no more than 50%. It is not recommended to drain the battery below 80% of its total capacity. This rapidly causes battery failure.

The lead-acid battery’s degree of discharge and idle voltage dependence are displayed in the table.

The cut-off voltage, or voltage at which the load should be disconnected from the battery, is roughly indicated in the table. Because the voltage of the battery connected to the load is always less than the battery’s idle voltage, it is regarded as approximative. The load is disconnected and the idle speed parameters are measured a few hours later. It is preferable to follow the manufacturers’ recommendations and controller readings when determining the cutoff voltage (most devices display the percentage of battery charge).

Alkaline batteries

Because alkaline batteries can release energy gradually until they are fully depleted, they are ideal for autonomous power supply systems because of their cyclic operation design.

Additionally, a battery of this type will gain more capacity during recharging the further it is discharged (this is known as the memory effect).

The fact that alkaline batteries do not charge well, or at all, at low currents is a major drawback. By accurately estimating the solar panels’ capacity and installing an appropriate controller, this kind of issue can be resolved.

In conclusion, it is preferable to purchase alkaline batteries for solar panels if at all possible.

Gel batteries

Lead-acid gel batteries are chosen in favor of automobile batteries if the drawbacks are too great for the customer to bear and they are unable to get an appropriate alkaline battery. Due to their features, they have a 10-year service life, are maintenance-free, and are best suited for independent solar and wind energy systems. The high cost of gel batteries is a drawback.

Lithium-ion (or lithium-iron-phosphate) batteries are another type. They are, incidentally, acknowledged as the top batteries for self-sufficient systems.

Considering the "high price of these devices, very few people use them in DIY systems."

Choosing an inverter

The primary purpose of the inverter is to change the batteries’ DC current and standard voltage into a 220V household AC voltage. The inverter’s output voltage graph is shaped like a sinusoidal wave. Additionally, the inverter must generate a voltage with either the modified sine (meander) or the correct sinusoidal shape of the graph (pure sine), depending on what consumers are connected to the power supply from the SB. What precise behavior does the voltage graph exhibit at the inverter’s output? This is dependent on the device’s features.

A few other electrical appliances, such as computers, TV models with switched-mode power supplies, and electric heaters, also function steadily on "modified sine." However, buying inverters that provide a "pure sine" at the output is advised only for the experienced. Typically, the device’s characteristics specify the output signal’s shape.

It’s important to consider both the inverter’s power and the shape of the output signal when selecting one. It is recommended that the operating (rated) power be 25–30% greater than the total power of the consumers who are continuously engaged in the work.

In this instance, the inverter’s peak power must be greater than any potential short-term load it may be subjected to. We are discussing the load that results from turning on multiple high-starting-power consumers at once (such as a pump motor, refrigerator, etc.).

Usually, the maximum power is also mentioned in the inverter’s characteristics. Although it is higher than the rated power, it is less than the peak power. This parameter shows the maximum short-term load at which the device can function for five to ten minutes without experiencing a malfunction.

When selecting a gadget, inverter efficiency is also crucial. It measures the amount of electricity lost while the device is in use and is subject to variation within the following parameters: 85–95% (variable based on model). Selecting a device with an efficiency of 90% or higher is advised. After all, we only have to pay for the inverter once, but we will always be paying for its poor efficiency.

Lead-acid battery inverters that are directly connected to them need to prevent deep discharge of the battery. This feature is integrated into most modern inverters. In addition, the user has the option to modify or the manufacturer’s set the load cutoff threshold.

Hybrid and combined inverters are frequently utilized in autonomous power supply systems in addition to conventional inverters. Combined: able to combine an inverter’s and controller’s functions. With hybrid inverters, users can draw power from batteries as well as the mains. released on econet.ru

How to choose

When selecting an appropriate controller for solar battery charging, there are a few crucial factors that you should keep in mind. The incoming voltage comes in first.

There are requirements that must be met by this indicator’s maximum value. These kinds of devices are occasionally designed with multiple batteries. As a result, all of the batteries that are connected to the device in various ways provide voltage to the circuit at the same time. A specific voltage is needed for the device to operate correctly; the values of this voltage shouldn’t be higher than the guidelines supplied by the manufacturer.

First is the incoming voltage. This indicator’s maximum value needs to adhere to specific standards. These devices can occasionally be built using multiple batteries. Consequently, all of the batteries that are connected in various ways provide the voltage to the device’s circuitry simultaneously. A specific voltage is needed for the device to operate correctly; this voltage cannot be higher than what the manufacturer specifies.

Some nuances need to be considered in order to make sure that the voltage values meet the necessary standards:

• overestimation of all indicators of the design for solar battery charging – for advertising purposes;
• Instability of various processes occurring in the photocells of the device during strong light flashes, and the energy values that affect the voltage in the device during the idle operation of the battery can be significantly exceeded.

The rated current is the second crucial factor. This indicator has a different value for every kind of device. As a result, the required power standards should be specified in advance when selecting a specific device. These indicators are crucial to the controller’s efficient operation. These values are sent to the battery by the device. The gadget might malfunction if it doesn’t get the required power and an unforeseen circumstance happens.

When the device’s batteries run low, the voltage value is used as the foundation for calculating the power value. The output current and voltage that the solar panel produces must be multiplied. Following that, the result should have 20% added for a reserve.

The kind of load is a crucial consideration when selecting a controller. It is not recommended to connect different household appliances to this device. Because different technologies were used in the device’s design to account for the full load inherent in the battery properties, this will lead to the controller failing. It is vital to use the device exactly as intended in order to prevent such scenarios.

MPPT

The MRRT is the most sophisticated kind of solar panel charge regulator currently on the market. It enables you to generate more electricity with the same number of solar panels at a higher efficiency. Any mppt module’s basic method of operation is to monitor the "maximum power point."

Every mppt controller continuously measures the voltage and current, and the microprocessor analytical unit determines the best ratio between them to produce the maximum amount of power. The processor considers the stage of the charging process in addition to current and voltage ratings.

More voltage from the solar panels can be extracted with mppt controllers, and this extra voltage is then transformed to the ideal voltage for battery charging (which typically isn’t the same as the passport supply voltage). When compared to PWM controllers, the solar system’s overall efficiency rises by 15–35%. Moreover, MRRT technology enables operation even in situations where panel illumination is 40% less.

The following diagram provides a summary of the benefits of MRRT modules:

You can use smaller wires and extend the distance between the unit and the solar panels thanks to the mppt controller’s ability to produce a high voltage at the output.

Battery charging scheme

The first thing you need to do is to figure out the charging circuitry of your battery pack. There are two main technologies: MPPT and PWM. The first stands for Maximum Power Point Tracking and translates to "maximum power point tracking". Devices that support this technology are on average 30% more efficient than standard PWM batteries, as the latter do not use the full power of the solar panel, and as a result some of it is simply lost. The principle of operation of a battery controller with MPPT charging scheme is based on detecting the highest power points and distributing the total amount of energy in the access medium. The latest models of such controllers have ultra-high detection speed of maximum power points, which is counted in seconds, and are 10% more efficient in operation than standard MTTP devices.

Adjusting the parameters and selecting a charging circuit

An appropriately chosen voltage in the network plays a significant role in determining the battery’s service life. Depending on the battery type, there are differences in voltage at the same charge sites (acid, lithium-ion, AGM, helium, bulk). On the other hand, the battery charge controller features parameter functionality that lets you tailor it to a specific kind of battery device.

Temperature sensor

The presence of an external or built-in temperature sensor is one of the indicators of a quality controller. The sensor’s job is to measure the device’s temperature and adjust for variations in the charging voltages’ temperature. The battery pack’s life is extended and premature wear is avoided by this regulation of the charge voltage based on the battery’s temperature.

Schematic diagram of the solar power station

Let’s examine the components and functionality of a solar system for a rural home. Its principal function is to transform solar energy into 220 V electricity, which powers most home appliances.

The primary constituents of the SES are:

1. Batteries (panels) that convert solar radiation into a DC voltage current.
2. Controller regulating the battery charge.
3. Battery pack.
4. Inverter converting the battery voltage to 220 V.

The equipment can function in a range of weather conditions and temperatures, from -35ºC to +80ºC, thanks to the battery’s design.

It turns out that correctly installed panels operate equally well in the summer and winter, with the exception of one circumstance: clear weather, when the sun’s heat output is at its highest. The efficiency of operation is significantly decreased in cloudy conditions.

SES is very efficient in the middle latitudes, but not so much that it can supply large houses with all of their electricity needs. The solar system is typically thought of as a backup or additional source of electricity.

A single 300 W battery weighs 20 kg. The panels are typically mounted on the facade, roof, or unique poles that are erected close to the homes. The plane must be turned toward the sun, angled at an ideal 45 degrees to the ground, and have sunlight fall perpendicularly.

In order to control the panels’ position and keep an eye on the sun’s movements, a tracker is ideally installed.

Tempered anti-shock glass, which can easily withstand hail or heavy snow loads, protects the upper plane of the batteries. However, if the coating is not maintained, damaged silicon wafers (photocells) will cease to function. Therefore, caution must be taken.

The controller carries out as many tasks as it can. Apart from its primary function of automatically regulating battery charge, it also manages solar panel energy supply, preventing the battery from being completely discharged. The controller automatically unplugs the battery from the system after it has reached full charge. Contemporary gadgets come with a control panel that displays the battery voltage on a display.

Gel batteries are the best option for DIY solar systems because they can run continuously for ten to twelve years. They lose roughly 15–25% of their capacity after ten years of operation. These are completely safe, low-maintenance devices that don’t release any toxic emissions.

The panels still function in the winter and overcast conditions (provided that the snow is regularly removed from them), but the amount of energy produced is decreased by five to ten times.

The purpose of inverters is to change the battery’s DC voltage into 220 V of AC voltage. Technical attributes like power and voltage quality are different between them. Consumer electronics and compressors are two examples of modern appliances whose quality can be most "capricious" when it comes to sinus equipment.

Review of Household SES:

Photovoltaic cell batteries paired with solar panels

Controller for controlling the charge of the batteries

Gel-filled battery pack

Voltage converter to 220 V: inverter

It’s important to remember that home power plants can run a TV, lighting system, refrigerator, and occasionally a submersible pump. More potent and costly equipment is required to supply the energy needed to run a boiler or even a microwave oven.

The basic layout of a solar power plant, comprising the essential components. Each of them carries out a specific task that the SES could not function without.

Although there are other, more intricate plans, this one is the most widely used and universal in the household.

What is a charge controller and what kind of controller is it?

Every component of the aforementioned plan serves its purpose:

• The solar module senses light radiation and converts it into direct electric current. The module itself consists of many semiconductors (photocells);
• A battery (battery pack) is used to store and dispense energy from the modules;
• An inverter is used to convert direct current into alternating current with changing output values of frequency and voltage in the network.

Here may arise a legitimate question: "And then why a controller, because you can directly connect the solar module and battery pack?". If this is not done, the charging current will constantly flow to the battery terminals, which in turn will cause the voltage to rise. Sooner or later, depending on the type of battery, the voltage will reach the maximum value of 14.4 V, after which the process of overcharging the battery and boiling off the electrolyte in it will begin.
And this is a direct way to shorten the life of the battery. You can control this process manually, using a simple voltmeter, and turn off the power at the right moment. But in this case, a person will be permanently tied to the system and call it autonomous will no longer be possible.

The link in the chain that needs to monitor the automatic charging and discharging of battery energy is the controller. It also carries out a variety of other tasks, the list of which varies depending on the model and type:

• Automatic connection of the battery and modules by the charging circuit;
• Selection of optimal modes of charge accumulation;
• Full control of the process and, if necessary, disconnect or connect consumers;
• Support for correct polarity;
• Protection against short circuits, interruption of power supply (break);
• Keeping track of the battery charge levels;
• Energy consumption control, etc.д.

It is required to assemble current solar systems by hand or select one of the three available types:

Over-discharge protection

When the voltage reaches critically low values that make the very functioning of the device problematic (usually a range of 2.3-2.5V), the corresponding MOSFET transistor, which is responsible for supplying current to the cell phone, is turned off. Next, it goes into sleep mode with minimal consumption. And there is a rather interesting aspect of operation here. So, until the voltage of the battery cell does not become more than 2.9-3.1 V, the mobile device can not be turned on to work in the normal mode. Probably, you may have noticed that when you connect the phone, it shows that it is charging, but it does not want to turn on and function in normal mode.

Conclusions and useful video on the topic

Sometimes the urge to build home appliances yourself outweighs the easier option of purchasing a low-cost gadget. Watch the video to see what came of it:

When evaluating the potential for producing electronics on one’s own, regardless of the intended use, it is necessary to acknowledge that the era of "self-made" products is drawing to a close. Electronic devices that are already assembled and modular parts for nearly all household products are oversaturated in the market. There’s only one thing left for amateur electronics enthusiasts to do: DIY construction assemblies.

Step	Description
Gather Materials	Collect items like a microcontroller, solar panel, voltage regulator, and wires.
Assembly	Connect the solar panel to the voltage regulator and then to the microcontroller.
Programming	Write or upload code to the microcontroller to manage solar panel output.
Testing	Check if the controller effectively regulates solar panel functions.

One clever and environmentally responsible method to maximize energy use in your home is to install a controller for a solar panel. Utilizing solar energy can help you cut down on the amount of energy you need from conventional sources, which will save money and have a positive environmental impact.

While building your own solar panel controller may seem difficult at first, the average do-it-yourself enthusiast can easily accomplish this with the correct materials and guidance. You can design a controller that fits your needs and budget by using easily accessible components and step-by-step instructions.

The ability to customize a homemade solar panel controller is one of its main benefits. With a DIY controller, you can create exactly what you need, in contrast to off-the-shelf options that might have extra features or restrictions. The choice is yours when it comes to adding more sensors or changing the charge parameters.

In addition, building a DIY solar panel controller is a worthwhile educational experience. It gives you knowledge about the inner workings of renewable energy systems, enabling you to make wise choices regarding the amount of energy you use and how to conserve it. It’s also a fulfilling project that can help you learn more about sustainable technologies.

To sum up, building a solar panel controller is about more than just saving energy; it’s also about managing your environmental impact and fostering a more sustainable future. You can use solar energy to heat and insulate your home and lessen your reliance on fossil fuels with a little work and creativity. Thus, prepare for this empowering journey towards a greener tomorrow by rolling up your sleeves and gathering your tools.

Video on the topic

TX-20BL solar controller review

🌞 Solar panel as a mini charger for garage and camping needs.

Connecting a solar panel

How to charge a battery from a solar panel.Two super ways

DIY | Homemade solar power plant charge controller on XH-M601 modules

How to make a solar power station with your own hands.