How Solar Charge Controllers MPPT Keep Your Batteries Safe

f you add a battery to your photovoltaic system, you can charge it up to use as backup energy in the future. Although this process is straightforward, some precautions should be taken to protect the battery from failure. To keep the battery safe, homeowners are advised to purchase solar charge controllers MPPT.

What is a photovoltaic panel voltage regulator?

A photovoltaic panel voltage regulator, more widely known as a solar charge controller, is a necessity for the safe charging of solar batteries. It is an integral part of most battery-based solar systems.

There are three main tasks that a solar charge controller has to accomplish.

The first task is to prevent overcharging. When a battery is fully charged and the current keeps flowing into it, the voltage gets too high, and your photovoltaic system may overload. The battery will degrade rapidly and, as a result, may overheat and even catch fire. So, when the battery reaches a specific high voltage, a charge controller reduces the flow of energy to the battery.

Besides dealing with high voltage, charge controllers protect a photovoltaic system against operating at low voltages. Since it is dangerous for solar equipment to over-discharge, charge controllers automatically disconnect non-critical loads from the battery when the voltage falls below a defined threshold. They do this through a process called low voltage disconnect, which is similar to their role in preventing overloading.

Not least of all, the third purpose of using them is to block reverse currents. Photovoltaic panels have an electronic diode that makes the current flow in one direction. During the night, when the panels don't generate power, they may pass some current in the reverse direction, causing a slight discharge from the battery. A charge controller blocks this current from entering the circuit.

Solar charge controllers MPPT vs. other types

Solar charge controllers can generally be of three types: 1- or 2-stage controllers, PWM, and MPPT.

Simple 1- or 2-stage options are the oldest and tend to be inefficient but affordable and reliable. They use shunt transistors or relays to regulate voltage in either one or two steps. In today’s off-grid solar industry, they are much less used than PWM and MPPT regulators.

A PWM (pulse width modulation) device regulates the flow of energy to the battery using a switch mechanism. The switch is open until the battery is fully charged. Then, the switch starts to open and close rapidly, which allows it to deliver a tiny amount of power to keep the battery full but reduces the average current. The downside of such regulation is reducing the average power of the system.

So what is MPPT, and how does it differ in terms of working principles compared to PWM? An MPPT (maximum power point tracker) device is a DC-to-DC converter that can optimize the match between the photovoltaic panels and the battery.

Solar charge controllers MPPT enable a solar panel to always operate at its maximum power point. Since the amount of sunlight landing on a panel changes throughout the day, the panel voltage and current continuously vary. To take the most out of your solar generation system and not reduce the current, as with PWM technology, MPPT finds the best voltage and current combination, allowing it to produce the maximum electric energy.

Solar charge controllers MPPT unceasingly track and adjust the voltage to generate the most power, regardless of the time of day or the weather. If it gets cloudy, your MPPT device will reduce the amount of current that is drawn to keep a desirable voltage at the panel's output. When the weather becomes sunny again, the MPPT will allow more current from the panel.

For instance, a photovoltaic panel with an operating voltage of 32V (Vmp) is connected to a 12V battery bank using both a PWM and an MPPT regulator. Using the PWM, the panel voltage must drop to match the battery voltage, so the power output is dramatically reduced. With the MPPT, the panel can operate at its maximum power point, generating much more power than with the PWM.

What are the pros and cons of MPPT regulators?

Charge controllers MPPT and PWM are both widely used today, and both of them can make your battery charging process safe. Let’s look at what advantages and disadvantages MPPT devices can offer in comparison with PWM alternatives.

If the deciding factor for you while choosing a regulator is efficiency, the MPPT will be the right fit for you. MPPT solutions demonstrate an impressive 94-98% efficiency level, which is 10-30% more power supplied to the battery than other types can show. However, in case you don’t need to squeeze every possible watt out of your solar panels, you can consider other types of regulators.

If you are looking for a lower price, solar charge controllers MPPT may not be the best option. The PWM device is the cheapest solar charge controller available for photovoltaic panels and costs as little as 20-60 dollars for a unit, while the MPPT device is much more expensive, and its price ranges anywhere from 100 dollars up to 800 dollars, depending on the voltage (V) and current rating (A).

To take a helicopter view, here you can see the prices for some regulator models:

PWM 100V up to 20A - $40 to $120

MPPT 100V up to 20A - $80 to $200

MPPT 150V up to 40A - $200 to $400

MPPT 150V up to 60A - $400 to $800

MPPT 250V up to 80A - $800 to $1200

MPPT 300V up to 100A - $900 to $1500

Overall, solar charge controllers MPPT have both pros and cons. Generally, MPPT is a must if you have a large photovoltaic array where the additional energy production is valuable. For a small solar panel system where the efficiency is not that crucial, you might opt for a less pricey PWM regulator. Furthermore, solar charge controllers MPPT will most likely outperform PWM in cold climates.

Solar charge controllers MPPT top brands

The MPPT market is quite big. If you want to safely charge your solar battery without any worries but don’t know what MPPT regulator to choose, we will give you a brief overview of some most popular solar charge controllers MPPT brands.

Victron

Victron Energy, a world leader in independent electric power, is based in the Netherlands and specializes in producing equipment for off-grid solar systems, such as inverters, batteries, chargers, and monitors. In particular, this Dutch company is a reputable manufacturer of reliable off-grid battery inverter/chargers and high-quality MPPT regulators.

Victron Energy produces a vast range of voltage regulators, from small 10A PWM models, to high-efficiency 100A MPPT devices with high voltage inputs up to 250V. Most Victron regulator models have lots of features, and, at the same time, this brand's device is the easiest to use compared to many other products. One standout feature of Victron regulator models is built-in Bluetooth. Moreover, the VictronConnect app is well-developed – you can use one of the many battery presets or easily create and save custom charging profiles.

Renogy

Renogy, an American company based in California, has recently become popular on the solar market across the world due to its low-cost solutions, easy setup, and good MPPT tracking. Renogy manufactures lots of affordable inverters, DC converters, and voltage regulators in China. You will find the Renogy Rover regulator model in most of the top regulator models lists.

Renogy regulators are considered to provide good value for money. They have a tracking efficiency of up to 99% and a conversion efficiency of 98%. Renogy regulators can be easily operated, as well as connected via Bluetooth for pairing on smartphones. However, many reviews of the Renogy app state that it does not measure up, especially when compared to the VictronConnect app.

EPever

EPever is one of the largest Chinese manufacturers of cost-effective power products, including a wide range of MPPT regulators. Its Tracer and Triron series of MPPTs are particularly popular.

The EPever MPPT regulator can be used for various purposes, from camping trailers to marine uses. This MPPT device has an automatic system voltage recognition of 12 to 24 V and also has a function that allows it to remember settings for future use. Additionally, EPever MPPT comes with a multi-function LCD display to show system information. This model can also be connected to PC software or an MT50 tracker for constant monitoring.

Morningstar

Based in Chicago, Morningstar mppt 60 designs regulators, inverters, and accessories for off-grid photovoltaic systems. It has more than 4000000 off-grid photovoltaic products deployed globally since 1993.

The ProStar MPPT regulators are available in 25A and 40A versions with a 120V input voltage limit. The incredibly fast MPP tracking can perform a full voltage sweep in less than 1 second using the Trakstar technology. The ProStar design has been proven in over 20 years of use in the world’s most demanding installations. However, due to their extremely high price, ProStar MPPT regulators are out of reach for many photovoltaic system owners.

Conclusion: acquiring MPPT is a smart move

It is not worth skimping on an MPPT regulator for your photovoltaic system, as it won't be a significant portion of the total cost. However, if you don't invest in a good one, your batteries may only last a quarter of their expected lifetime. Ultimately, solar charge controllers mppt are powerful and feature-packed devices that should not be overlooked.

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