HOME NEWS MPPT solar controller: PWM and MPPT charge controller
Jun 16,2020

MPPT solar controller: PWM and MPPT charge controller

Like batteries, solar panels can be connected in parallel or series! Parallel wiring is to connect the positive (+) poles of all panels and connect all the negative (-) poles. This keeps the voltage constant but increases the current flowing into the controller.The series connection is to connect the positive (+) pole of one panel to the negative (-) pole of another panel, which will increase the voltage but keep the current unchanged.


Comparison of using series solar panels and parallel solar panels:

Tandem solar panels


No fuses are required, wiring is simpler and cheaper. Higher voltage instead of current means higher system efficiency.

Under certain lighting conditions, the tandem effect is better. The series connection is suitable for cloudy or low light conditions. If the sunlight received by the panel only outputs 13V, the two parallel panels still cannot output enough voltage (13.8V) to charge the battery. If connected in series, you can get a voltage of 26V, and then step down to get the proper charging voltage.(solar powered rv: universal solar panel classification)


Parallel solar panels


Larger wiring, fuses, and connectors are required. If one panel is short-circuited, each panel must be fused at the joint of the connector. As the current increases, the wiring must be larger.

Most PWM controllers require parallel wiring. The rated input voltage of these charge controllers is only a little higher than the battery pack. Therefore, if you have two 18V panels connected in series to wire 36V power to the PWM controller, the part with a voltage higher than 13.8V will be filtered by the controller.


Charge controller

The most basic function of the solar charge and discharge controller is to control the battery voltage and open the circuit. Also, when the battery voltage rises to a certain level, the battery charging is stopped. The old version of the controller mechanically completes the opening or closing of the control circuit, stopping or starting the power delivered to the battery.

Controllers are used in most photovoltaic systems to protect the battery from overcharging or over-discharging. Overcharging may vaporize the electrolyte in the battery, causing malfunctions, and over-discharging the battery will cause the battery to fail prematurely. Overcharge and over-discharge may damage the load. Therefore, the controller is one of the core components of the photovoltaic power generation system and the main part of the balance system BOS.

 Classic MPPT Solar charge controller eSmart3 Series

The solar panel cannot directly charge the battery. To convert the chaotic power generated by the solar panel into acceptable power for the battery, you also need a device, a solar charge controller. Under direct sunlight, most 12V solar panels can generate a voltage of about 16~20V. Batteries are relatively expensive, and if the charging voltage is too high, they will be damaged. The charge controller can adjust this.


PWM and MPPT charge controller


There are two types of controllers: PWM solar controller and MPPT solar controller, the following introduces the differences between the two:


PWM: pulse width modulation. The PWM solar controller is the second-generation technology. The working mode is the PWM control method, which can solve the problem of battery dissatisfaction. The charging conversion efficiency is 75 to 80%, but the solar panel is not fully utilized. When the solar panel generates 18v of electricity, the charge controller must convert it to a 13.8V voltage that is safe for the battery. This type of charge controller will directly filter out voltages higher than 13.8V, which will lose part of the electrical energy. PWM technology is very simple and has been used in solar systems for decades. And the price is cheap, and there are few internal parts.



MPPT: Maximum power point tracking, DC to DC transformer, can convert power from higher voltage to lower voltage.

MPPT solar controller is the third generation technology, the most high-end solar controller. The amount of power is unchanged (except for a small amount of loss in the conversion process). The battery can get more power because the total charging power has not dropped much. MPPT controllers can accept higher voltage inputs, so they have a better advantage when connecting multiple panels.


MPPT solar controller refers to a solar controller with a "maximum power point tracking" function, which is an upgraded product of the PWM solar controller. The MPPT solar controller can detect the solar panel voltage and current in real-time and continuously track the maximum power (P =U*I), the system always charges the battery with maximum power, MPPT tracking efficiency is 99%, the entire system power generation efficiency is as high as 97%, and the battery has excellent management, divided into MPPT charging and constant voltage charging And constant voltage float charge. With the advancement of technology and energy-saving, the trend of MPPT solar controllers replacing traditional PWM solar controllers is irreversible.


To generate maximum power, the maximum power point tracker scans the panel voltage to find the "best location" or the best combination of voltage and current to produce maximum power. MPPT is designed to continuously track and adjust the voltage to produce maximum power, regardless of the time of day or weather conditions. Using this technology, the efficiency of solar panels increases by 30% compared to PWM solar controllers. (Please note that only high-end MPPT controllers can detect partial shadows or be able to track multiple power points).


In the above, we know that there are two ways to connect solar panels: series and parallel. If you are using a PWM solar controller, you can only choose the parallel method. This means that more combiners, fuses, and larger wires are needed. All of these require more money and installation time. If you are using an MPPT solar controller, you can directly connect multiple panels in series to obtain a higher input voltage, and let the MPPT solar controller control the subsequent charging. No need for a combiner, fuse, or oversized wires. Therefore, the MPPT charge controller is the preferred solution.

 Classic MPPT Solar charge controller

How to maximize MPPT?


Winter and/or cloudy or hazy days-when extra electricity is needed most. Cold weather-Solar panels work better in cold temperatures, but without MPPT, you will lose most. Winter is most likely cold weather: the sun is very low and you need to charge the battery to the maximum extent.

Low battery power: The lower the battery level, the more current MPPT consumes-this is another time when additional power is needed most. You can have both conditions.

Longer wires-If you are charging a 12-volt battery and the panel is 100 feet away unless very large wires are used, the voltage drop and power loss can be significant. That can be very expensive. However, if you have four 12-volt panels connected in series at 48 volts, the power loss is much smaller and the controller will convert the high voltage at the battery to 12 volts. This also means that if you have a high-voltage panel set to power the controller, you can use thinner wires.


What is the charge controller load output (LVD)


Most charge controllers have three sets of terminals. One set is for batteries. A set of access panels. Then, the third group usually displays a LOAD or LVD. The load output is intended to power all small electronic devices through the charge controller. A function of this output is that if the battery voltage drops below a certain voltage, the charge controller will cut off the output to prevent further battery consumption. If your battery cannot be fully charged every day, some smart charge controllers will also adjust this voltage cut-off value.


But this function is not so easy to use, because it is only suitable for low-power devices. You cannot run inverters through them.


Benefits of solar panels:


Off-grid life refers to living in a place where the main grid cannot provide services. Remote houses and cabins can benefit greatly from the solar system. The installation of telephone poles and cables from the nearest main grid access point no longer requires huge fees. Solar energy systems may be cheaper, and if properly maintained, they can provide up to thirty years of electricity.


In addition to using solar panels to live off-grid, the biggest benefit that solar energy may bring to you is that it is both clean energy and renewable energy. With the advent of global climate change, human beings should make every effort to reduce the pressure on the atmosphere caused by greenhouse gas emissions. Solar panels have no moving parts and require little maintenance. They are durable and carefully maintained for decades.


The main functions of the new solar controller:


Overcharge, over-discharge, and overvoltage protection: When the charging voltage is higher than the protection voltage, the battery is automatically turned off to charge. After that, when the voltage drops to the maintenance voltage, the battery enters the floating charge state, and the floating charge is turned off when it is lower than the recovery voltage. Enter the even charging state. When the battery voltage is lower than the protection voltage, the controller automatically turns off the output to protect the battery from damage; when the battery is charged again, it can automatically restore power. When the voltage is too high, the output is automatically turned off to protect the electrical appliances from damage.

Load over-current and short-circuit protection: After the load current exceeds 10A or the load is short-circuited, the fuse is blown and can be used after replacement.

With anti-reverse charge function: the Schottky diode is used to prevent the battery from charging the solar battery.

With anti-lightning function: when a lightning strike occurs, the varistor can prevent the lightning strike and protect the controller from damage.

Reverse connection protection of solar cells: "+" and "-" polarities of solar cells are reversed and can be used after correction.

Reverse battery connection and open circuit protection: The battery "+" "-" polarity is reversed, the fuse is blown, and can be used after replacement. In case the battery is open if the solar battery is charged normally, the controller will limit the voltage across the load to ensure that the load is not damaged. If at night or when the solar battery is not charged, the controller will not receive power because of its own power. There is no action.

Self-check: When the controller is affected by natural factors or is improperly operated, the controller can be self-checked to let the person know whether the controller is intact, reducing a lot of unnecessary man-hours and creating conditions for winning project quality and duration.

Recovery interval: It is the recovery interval made for over-charge or over-discharge protection, to avoid the load resistance caused by the line resistance or the self-recovery feature of the battery.

Temperature compensation: monitor the temperature of the battery, and correct the charge and discharge values to make the battery work in an ideal state.

Light control: It is mostly used for automatic lamps. When the environment is bright enough, the controller will automatically turn off the load output; and when the environment is dark, it will automatically turn on the load to achieve the function of automatic control.


Solar inverter TPS series

This inverter power supply can provide an AC power solution in the event of a power outage or when AC power is not available, it charges solar energy into the battery and converts the 12V/24V/48V DC power supply to 110V/

The 220V standard AC power supply and the built-in low-frequency transformer ensure its strong load capacity, making it an ideal inverter for solar power generation systems in homes and small businesses. Its built-in UPS system automatically switches the inverter from AC bypass output to backup battery output. Advanced DSP control integration guarantees maximum efficiency and reliability.

Digital LCD display, 1000W ~ 6000W, pure sine wave output, UPS function, built-in 10A-50A adjustable AC charger, built-in 60A MPPT solar charger controller. Reliable continuous long-term performance, comprehensive protection system: overheat protection, overload protection, short circuit protection, etc.

Low frequency DC to AC solar inverter with MPPT charger TPS series

Solar inverter TPS series product introduction:

The pure copper DC positive input lug is connected to the positive terminal of the battery.

The pure copper DC negative input terminal is connected to the negative terminal of the battery.

Battery temperature compensation port/remote control port. The RS232 communication port needs to be connected to a PC and monitoring software, and communication settings are charged separately.

AGS port, connected to the starter of the generator, when the battery is discharged to empty and the inverter is automatically shut down due to the battery under-voltage protection, it will send a start signal to the gene

-raptor (must have an automatic start function) to activate the generator.

Thermally controlled cooling fan.

The internal highlights of the solar inverter TPS series

1 The power module of this inverter, this power model is based on the TI 2000 series 32-bit high-performance DPS processor design.

It uses a TLP 250 optocoupler to implement full-bridge drive inverter technology, and four 15KUF/80V high-power electrolytic capacitors ensure that ripple and internal resistance are minimized. High-quality EMI filter inductor can effectively protect the load equipment from surge and interference.

The EI laminated power transformer is made of brand-new silicon steel and high-quality windings, ensuring high efficiency and strong power generation capacity. (1-3KW)


How to buy a controller?


Generally, at least 7.5A per 100W of solar energy. Generally, a conventional 30A charge controller can be used, and a 100W panel can be added in the future. If you buy a larger one than 30A, you can.


How to install the controller?


The solar panel is always connected at the last time. The controller should be installed as close to the battery as possible, and leave enough space for ventilation. This can reduce current consumption. It can also help the controller with a temperature sensor inside to accurately estimate the battery temperature, to perform the correct charging.

Do not install a charge controller above the battery. You don't want any gas to interfere with the controller's electronic equipment. Also ensure that the blown fuse is installed close to the battery so that any system short circuit will not cause a fire.