Solar Charge Controllers: Everything You Need to Know Before Buying

This article will discuss everything you need to know about Solar Charge Controllers:

Everything You Need to Know Before Buying.

Our ancestors have been toiling under the tyrannical heat of the sun for millennia, but it was not until very recently that we are able to efficiently convert its power into electricity.

After nearly 200 years since the discovery of the photovoltaic effect, we are now able to harness the power of the sun in a very cost-effective manner — solar panels are getting cheaper and are delivering more power than what we used to imagine.

Indeed, it is not that uncommon these days to hear people talk about how solar energy is the future of power generation.

Solar power is gradually becoming an ideal alternative source of power to fossil fuel, and for many good reasons.

For one, fossil fuel is a finite resource that humanity is quickly using up in its quest for industrial progress.

Second, power plants that use fossil fuel give off massive amounts of carbon dioxide that further exacerbate the problem of global warming.

Lastly, solar power technology simply is getting better as time passes and is currently the most viable way to cleanly generate electricity.

It also helps that, as the world’s need for alternative sources of power grows, the development of technology relevant to solar power generation is going forward at breakneck speed, to the point that not only power generation companies and huge industries are able to afford solar power.

It is now possible for everyone with some cash to spare and a bit of care for the planet to set up their very own solar power generation system at home.

That is not to say that setting up your very own solar power generation system is a walk in the park.

It is definitely not as straightforward as hooking up a solar panel to your local electrical network.

There are plenty of components that come to play here, and among the most important is the solar charge controller.

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What Is a Solar Charge Controller and How Does It Work?

People who have experience setting up a solar power generation system know that solar panels cannot generate any power at night and can only do so little during dark, cloudy days.

That is where solar batteries come in.

Electrical networks hooked up to a solar panel takes power from these batteries at times when the solar panel is not generating any electricity.

Here’s the thing, though: the output of a panel varies depending on various, mostly weather-related conditions, and many times, it can go through the roof.

Solar batteries, on the other hand, can only store a finite amount of solar energy that then goes to the load.

can get overcharged, and when it does, its voltage can be a lot higher than that of the solar panel.

What does this imply, you ask?

Well, in electric circuits, the electrons carrying current moves from a point with higher potential energy — where there is a higher voltage — to another with lower potential or lower voltage.

Current thus moves away from an overcharged battery to both its load and the lesser charged solar panels, resulting in it draining really fast.

This phenomenon is called reverse current, and it also happens during nighttime when the solar panel is not generating any power and thus have a very low voltage.

This problem is what the solar panel charge controller practically provides a solution to.

Such charge controllers regulate the amount of current that gets into the battery from the solar panel, thereby preventing overcharging during the daytime.

In other words, it manages the power as its primary function, although more advanced controllers also come with the likes of lighting and load control.

It should also be noted that overcharging can damage your battery and shorten its lifespan, so a charge controller can help you maximize the use of your batteries and save some money as well.

What Are the Main Types of Charge Controller?

Solar charge controllers come in two classifications, and these are the following:

Pulse width modulation (PWM) by Wikipedia
Maximum power point tracking (MPPT) by Wikipedia
  1. Pulse width modulation (PWM) – You ca connect the solar power directly to the battery bank. It regulates the input to the battery by pulling down the output of the solar panel to the same level as the former. This considers the fact that the battery’s voltage rises as it charges, thereby necessitating that the solar panel’s voltage matches the nominal voltage of the solar batteries.
  2. Maximum power point tracking (MPPT– It measure the voltage at maximum power point (Vmp) of the panel and then convert the photovoltaic system (PV) voltage to equal that of the battery voltage. Considering the concept that the power entering the charge controller is equal to that of the power coming out of it, the current is raised once the voltage is lowered to match that of the battery, allowing the network to get more power from the panel. The MPPT, as you can imagine, costs more than PWM charge controllers.

What Are the 10 Best Solar Charge Controllers in the Market Today?

Now that the definition and the classifications are out of the way, here are the best solar charge controllers that are currently available commercially:

1. Epever MPPT (EPSOLAR Charge Controller)

It is an advanced, algorithm-based solar charge controller.

It provides multiple load controls, remote communication through desktop software and mobile app thanks to its RS-485 and Modbus communication bus and protocol, and a very fast MPPT control algorithm.

It comes with a multi-function LCD screen that allows user programming for AGM, flooded, gel, liFEPO4, Li(NiCoMn), and sealed battery types.

With a peak conversion efficiency that can go as high as 98%, it is one of the most cost-effective charge controllers in the market.

2. Renogy Wanderer Solar Charge Controller

It is yet another advanced solar panel charge controller designed specifically for off-grid applications, it being compatible with 12V or 24V battery banks with a charging capacity of 10 Amps.

It integrates high-efficiency PWM charging that can be set for AGM, flooded, gel, or lithium batteries to maximize system performance and increase battery life.

The PWM charging is composed of four stages, namely bulk, boost, float, and equalization charge.

To further preserve battery life, the controller integrates a self-diagnostic system and electronic protection from overcharging, reverse current flow, short circuit, and the like.

3. Victron SmartSolar MPPT 100/20

It primarily features an intelligent system that makes installation easy for people who are new to setting up solar power generation systems.

It primarily features a Bluetooth management system that allows for remote monitoring and system updates through smartphones or relevant Victron devices.

Its MPPT control features a three-step charging process to extend your system’s battery life.

Meanwhile, LED indicators to provide real-time updates on the charging process and lets you diagnose system faults through blinking signals.

4. WindyNation P30L

It is a PWM solar panel charge controller that features a digital display that provides vital information on the system whilst working as an interface for the user to configure the solar driver.

It works best for 12V and 24V batteries, and one of its features identify the battery voltage level upon initial connection while providing a 30 Amp charging current.

Another noteworthy feature of this charge controller is a battery temperature sensor that ensures optimal temperature by introducing compensation.

These are complemented by an array of built-in circuit protection against discharging, overcharging, overload, reverse current flow, reverse polarity, and short circuit.

5. HQST 30 from High-Quality Solar Technologies

It is another noteworthy PWM controller.

It features a smart and multi-functional solar charge controller that comes with dual USB ports, making it compatible with modern electronic devices as well as HQST portable panels.

Its microprocessor automatically detects 12V or 24V system voltages and allows adjustments in charging parameters with the help of temperature compensation.

You can configure this device’s settings through an LCD display, including charging and control parameters.

While it is already well-protected from common issues such as discharging, overcharging, and reverse current, it also features protection against installation errors.

6. Morningstar Prostar MPPT

It is notable for its high levels of protection against various environmental and electrical hazards including current surges due to lightning strikes.

It is thus unsurprising that this particular brand has a wide range of operating temperatures with a maximum at 60°C.

Available in 25 Amp and 40 Amp versions with a 120V input voltage limit, it features a very fast MPP tracking that can cover the entire range of the system’s voltage in just a second through the use of Trakstar technology.

Unfortunately, it does not have WiFi or Bluetooth monitoring that is becoming increasingly common among advanced charge controllers.

7. Renogy Rover

It is packed with plenty of features that you would expect from an advanced MPPT charge controller, but the whole package comes at an affordable cost.

These features include in-built load control terminals, a Bluetooth adapter, and a clear display that comes with an intuitive interface that offers plenty of settings that the user can configure.

The MPP tracking is very decent too. On the downside, the output is limited to 20 Amps and the cable terminals are too small.

8. Rich Solar 20A MPPT Solar Charge Controller

It primarily features an advanced dual-peak tracking technology which makes the controller still able to accurately track the maximum power point even if the panel fails or is shadowed by a nearby obstacle.

It also comes with an LCD display that provides you with programmable charging parameters; unfortunately for this display, it has no backlight.

This is a decent device overall, though, except for the fact that it is limited to 20 Amps.

9. Onesolar Solar Charge Controller

It is a reliable model that comes at a very affordable price. It is very durable for a rather lightweight controller, and it provides your battery with multiple layers of protection.

Its ultra-fast tracking will not leave you wanting for higher tracking speeds, and the LCD display provides a very intuitive way to monitor the charging.

It also supports four charging options, namely flood, gel, sealed, and user-defined.

10. ALLPOWERS PWM 20A Solar Charge Controller

It is one of the best models when it comes to small solar power generation systems like in small homes and RVs.

Its main selling point is its affordability and compatibility with small solar panels.

It features a four-stage PWM technology and a three-stage process — bulk, absorption, and float — that protects your battery.

It also comes with an easy-to-use display that shows essential data and 5V/3 Amp USB ports.

The downside, however, is that it can only be used on small systems and it is not compatible with lithium-ion batteries.

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