A large scale solar panel system, for example one that powers your home, camper or RV, requires regulation to prevent battery damage. A solar charge controller is the device that does this by acting as a regulator and barrier between your power generation source, solar panels, battery and final energy load. In short, solar charge controllers guarantee correct energy flow and power efficiency.
There is a very wide range of solar charge controllers on the market so choosing and comparing the right model for your needs can be challenging or downright daunting for novices in the solar sphere. Voltage, ease of use and power output are just some factors that we will be considering. But not to worry, because as with any gadget all you need to do is some research (all of which will be covered in this article).
Whether you need to power up your entire household or just your shed or if you’re searching for improved power capacity as opposed to a multipurpose technologically advanced option. We will be looking at all the vital characteristics that make up the perfect solar charge controller catered to your needs. All these introductory precautions come for a reason. Solar charge controllers are pieces of high-tech equipment and can pose a serious investment for first timers, that is why reviewing and research are so important.
Editor’s Picks
Before going into our full list we’ve reviewed the top three solar charge controllers on the market in 2021.
Our top pick due to its incredibly high output, advanced tech and intelligent management system. Digital features geared towards intuitive usability such as its wireless Bluetooth allowing you to connect with smartphones is a feature which make it perfect for novices to solar system installation.
Our premium pick. The Outback Flexmax 80 is undoubtedly one of the best solar chargers on the market today. It supports a vast array of different system designs and battery types and has a massive max input voltage capacity that makes it perfect for off-grid powering. Its streamlined management and programming also allows for advanced configuration settings.
Our ideal entry-level and low budget option. Affordable but still offering a sleek design and some high-tech features such as Bluetooth connection capabilities, meaning it can be configured and monitored remotely. This solar charge controller supports both 12V and 24V solar panels and offers a decent maximum current rating for its size and price.
How Do Solar Charge Controllers Work?
The ability to harness solar power by using solar panels is surely one of the modern world’s greatest advancements. Free, green, and limitless, the power of sunlight is ever more increasingly being used by national electricity grids, governments, and home and business owners to power their appliances and batteries. However, as with all weather-dependent renewable power sources, solar PV systems fluctuate constantly and (sometimes) greatly in the wattage and voltage of electricity they produce.
Unfortunately, for all the merits of solar power, its innate tendency to fluctuate in output can be detrimental to the health of batteries and the electric grid, as well as unreliable when it comes to the direct powering of appliances. To put it simply, if you’re attempting to charge a 12V battery with a solar system, then it would begin damaging that battery as soon as sunlight was strong enough to cause it to produce more than 12V. Equally, it would not charge the battery, or would take an inordinately long time to charge it, if the solar panels did not receive the required levels of sunlight.
Thankfully, we have solar charge controllers. Solar charge controllers are, as we stated in the introduction, an integral part of any PV system or solar array. Solar charge controllers effectively work like dams on rivers do, they act as a barrier between the electricity produced by solar systems, and the batteries or appliances they are intended to charge. The charge controllers then allow through to said batteries/appliances only the compatible amount of voltage, and only up to the point at which the battery is 100% charged, so as to prevent damaging the battery/appliance through overcharging (a lot like solar battery maintainers do).
One of the most common types of solar charge controllers (for there are many varieties) is the MPPT charge controller. MPPT stands for ‘maximum power point tracker’, and is one of the most versatile and useful charge controllers on the solar energy market today. In addition to regulating the voltage sent to the appliances from the solar array, and preventing overcharging, MPPT controllers are also designed to maximise the efficiency of the energy produced by the solar array, or even on an individual panel level. These controllers adjust charging rates based on the receiving unit’s charge level, ensuring that the electricity produced by the solar array is done so to most efficiently match the requirements of the individual system it is powering. Furthermore, MPPT solar charge controllers free up the solar array owner to install solar panels whose voltage outputs can be much greater than the required voltage input of the receiving unit/battery (i.e. you can have a 50V panel charge a 12V battery safely and without damaging it, thanks to an MPPT solar charge controller).
Pros and Cons of Solar Charge Controllers
Like all modern technology, there are both ups and downs, pros and cons to solar charge controllers. Here are the most important of those to consider before buying:
Pros:
- Solar charge controllers free you and the solar panel designer to install almost whatever voltage of solar panel you like, without having to worry as to how compatible it is with the unit you intend to power. You can power a 12V battery with a 24V solar panel without worrying about overcharging it or overloading it with too high a voltage, since a solar charge controller will only feed the requisite 12V to the battery, and no more.
- Installing solar panel arrays is an expensive venture, and as such, you want to make sure that it’s going to last you. Truly the only safe and affordable way to do so is to get yourself a high quality charge controller, or system of solar charge controllers. Not only will they automatically optimise your solar panels’ outputs, and protect your batteries, but they also allow you the user to oversee live the wattage, voltage, and charge levels of your entire solar system.
- Solar charge controllers often block reverse current, too. When night falls and the sun has set, batteries charged by solar panel systems can often begin discharging via reversing the current back to the solar panels. Solar charge controllers stop them from doing this, maximising their charge levels even when the solar panels aren’t functioning due to lack of sunlight.
Cons:
- On the expensive side. Whilst not all solar charge controllers are expensive, we recommend opting for as high quality a controller as you can, since it is going to perform one of the most important tasks in your PV system. As such, you will find that solar charge controllers can be pretty expensive. Still, as is often the case when paying more for high quality products: rather do so now, and save on maintenance and replacement costs later, than skimp on cost and wind up with an ineffectual, fragile product.
The Best Solar Charge Controllers Reviewed
Let’s take an in-depth look at some of the best solar charge controllers to choose from today.
Victron SmartSolar MMPT
- Brand: Victron
- SmartSolar MPPT 100-Volt 30 amp
- Anytime anywhere remotely control
Our top pick is a tremendously reliable and durable solar charge controller from a high-quality premium brand, Victron Energy based in the Netherlands. The defining feature is its wireless Bluetooth connectivity and extremely intuitive management system which allows remote monitoring and updates your smartphone on any charging issue in real-time. This makes it perfect for those unfamiliar with solar powered system installations.
It has an integrated LED display system to check progress and if needed, troubleshoot system fault situations. This user-friendliness is coupled with an extremely high current rating of 30 amps and a max PV input open voltage of 100V. This combined with its voltage rating of 12-24V make the Victron SmarSolar compatible with almost every available solar panel on the market today.
Lastly a lengthy 3-year warranty is included, though it may not be needed for this particular MMPT controller as it is highly durable and built to last. It is a versatile solar charge controller that can be used both in households and motor homes such as RV’s or houseboats.
Pros:
- Extraordinarily reliable and durable product
- User-friendly and intuitive management system
- Wireless Bluetooth connection for remote monitoring on your smartphone
- Very high current output rating and solar panel compatibility
- 3-year warranty
Cons:
- Requires an additional purchase for full battery monitoring
- On the expensive side
Outback Flexmax 80
- Brand: Outback
- Color: Black
- Backlit 80 character-display shows the current status
- OutBack Power Systems
- Active cooling and intelligent thermal management cooling
Our premium pick is an awesome product with some incredible tech and features despite its simplistic design and old-school green and black screen. This solar charge controller can handle very high amounts of DC volts and in turn, convert them to 12VDC to 60VDC for battery bank usage.
Its max input voltage is 150V with a maximum current output of 80A putting this model squarely in the top-tier division when it comes to efficiently handling high power currents. As with other next-gen solar charge controllers, a defining quality is its smart and streamlined management system and programming.
The Outback Flexmax 80 can be heavily configured and connected to the MATE system display, branded inverter and HUB communications. This makes it relatively easy to use even for beginners. Its elevated voltage input makes this solar charge ideal for large-scale solar panel systems for off-grid use, especially in rural areas (barns, sheds, warehouses, RVs or your own house).
Pros:
- Very high input voltage and current output
- Excellent converting capabilities
- Intuitive and versatile model that can be heavily configured
Cons:
- Does not come with a data cable
- On the expensive side
Renogy Wanderer 10A Solar Charge Controller
- Brand: Renogy
- Smart 4-Stage PWM charging
- Backlit LCD screen displays system operation
- Capable of charging over-discharged lithium batteries
A budget-oriented solar charge controller (indeed our best value pick) from a solid brand that still doesn’t skimp on additional features and offers some high-tech capabilities. It has an integrated Bluetooth system that even some heavy-duty models do not offer. This means it can be remotely monitored and configured with ease.
The maximum current output is just 10A but it makes up by supporting both 12V and 24V currents. This model also has an in-built 5V 2A USB port making this item an effective charger for compatible appliances ranging from smartphones to tablets and laptops.
This device is of the PWM type as opposed to the MMPT models (we’ll go more into detail the difference in the Buyer’s Guide). This means it offers less current handling capabilities than other units. Nonetheless this a sturdy and reliable option for lower energy systems.
Pros:
- Budget friendly
- Sleek and durable design
- Can function as a charger compatible with many devices
Cons:
- Significantly lower current output
- No warranty included
Binen 20A Solar Charge Controller
- Brand: Binen
- Color: 20A-Blue
- Multiple Protection Functions
- LCD Display
At only 16$ this solar charge controller by Binen is still a quality device which has advanced compatibility with 12-24V systems. With a discharge current of 10A and a built-in micro controller that automatically manages working of both the solar panel and battery of your solar power system. The dual USB outputs 5V/2.5A (max) support a comprehensive array of smartphones for charging.
The safety features of this solar charge controller are a defining trait offering short-circuit protection, open-circuit protection,reverse protection and over-load protection. The charge controller also possesses 3-stage PWM charge management which improves and streamlines energy on low to mid level solar systems.
One thing to keep in mind is the charge regulator is only suitable for lead-acid batteries of the OPEN, AGM, GEL type. It is not suited for nickel hydride, lithium, Li-ion batteries so check battery compatibility extensively before installation to avoid malfunctioning. To protect the lifespan of the battery, if and when the voltage of the battery drops below 8V, the controller will turn off automatically.
For such an affordably priced and compact model, the LCD screen it features is incredibly detailed and intuitive. The screen clearly indicates status and other data and can various modes can be switched to implement parameter configuration making this controller perfect both for your home but also for any subsequent industrial or commercial needs.
Pros:
- Exceedingly affordable (lowest price on our list)
- Built-in micro controller
- Advanced and reliable safety features
- Intuitive LCD screen
Cons:
- Does not work with certain batteries
- Settings are not very flexible
Renogy Rover 40A Solar Charge Controller
- Brand: Renogy
- LCD Screen & Multiple LEDs
- Die-cast Aluminum Design
- RS232 Communication Port
- Temperature Sensor
Another entry from a very well-established brand, this is one of the top-selling solar charge controllers on the market today, renowned for its power, reliability and intuitive use. The Renogy Rover features programming that will automatically detect any 12-24V DC system voltage by using advanced MMPT tech. It offers an astoundingly high tracking efficiency of up to 99% and a peak conversion efficiency of 98%.
Moving on to the composition, the die-cast aluminium build maximizes heat dissipation. The controller also continuously monitors battery temperature. In the event of over-discharging of lithium-ion batteries a preemptive error code detection will appear for easy and early self diagnosis.
The charge controller is exceptionally compatible with various deep cycle battery options including: sealed, gel, flooded, and lithium electronic protection and almost any combination of solar module and battery. The LCD screen it presents is also extremely intuitive and can be monitored remotely through the devices’ BT-1 Bluetooth model which can be paired with the Renogy DC Home app.
Pros:
- Very high tracking and peak conversion efficiency
- Sturdy build that maximizes heat dissipation
- Very advanced safety features and error prevention
- Compatible with wide range of batteries
- Bluetooth remote monitoring
Cons:
- Might need to be reset or reconnected in the event of overcast or inclement weather
Solar Charge Controller Extended Buyer’s Guide
Solar charge controllers are arguably the most important part of your solar system apart from the solar panels themselves. As they are high-tech pieces of equipment it is good to know how to use them, and as much as possible about them before investing in one.
Difference between PWM and MMPT solar charge controllers
As we’ve seen there are two main types of solar charge controllers, distinguishable by their acronyms PWM and MMPT. A PWM model or Pulse Width Modulation charge controller is basically a switch that works between the panels and the main battery. On the other hand, an MPPT or Maximum Power Point Tracking controller acts as a smart DC-DC converter.
PWM tech represents a more outdated model that can suffer low output in extreme temperature (both high and low). It forces the output voltage of a solar array to be decreased in relation to the battery. If you intend to enlarge your solar power system you will have to compensate with more wiring and cables. With seemingly only negatives, what is a possible advantage of a PWM model?
The answer is financial cost. MMPT models cost exponentially more but also usually offer more extra features. Obviously higher output but also increased safety features and much improved battery regulation. Some PWM models do outshine MMPT charge controllers but only in the lightweight category.
MMPT controllers allow up to 30% more power (handling much higher voltages) while also being exceedingly more power efficient. MPPT controllers are much more capable of handling temperature extremes and shoddy weather because they preserve battery output while compensating for lower power. They also convert voltage for both input and output sources, resulting in minimal power loss power.
Battery Voltage
The vast majority of solar charge controllers are in the 12-48V DC range, while the base standard is 12V. A higher voltage means more power and can make the difference in regulating the energy that powers a household or a few appliances. The model with the highest battery voltage reviewed on our list (the MidNite Solar Classic) works in the 12-72V which is enough to power up a very large-scale solar system effectively.
Maximum Input Voltage
A rule of thumb is that the best solar charge controllers are those with a higher base max input voltage. This means you can calculate the generated current and scale accordingly especially if you want enlarge a pre-existing solar grid system.
A higher max input will also account for varying weather patterns as well. We say this because Maximum Input Voltage is a tricky category. For example, a 12V panel may very well not be compatible with a 12V battery bank. This is because the sunsbrightness, weather and temperature are all unpredictable. This in turn means that most panels actually don’t run at their rated voltage. For that reason it is always a good move to aim a little higher.
Maximum Current Output
The number of amps that your controller will feed to your devices is calculated in Amperes via the Maximum Current Output value. This figure is vital as it determines the type and size of appliances you can effectively charge with solar energy. Be sure to choose the model with the output more suitable to your needs by taking into account: chargeable devices, size of your solar system and even dimensions of your house.
Ease of Use
A crucial category especially for beginners in the solar energy field. How intuitive a solar charge controller’s software and managing system is often a deal breaker. Models with configurable LED screens, functional data logging and remote management systems often are the most sought-after.
Safety
Though usually operating at lower energy than the standard electrical grid, some of these models have extremely high outputs and voltages. This means that a sudden surge of electricity can be dangerous. In the most benign of cases causing some damage to the controller itself or to the panels, but worst case scenarios such as electric shocks and fires should never be taken lightly. That is why models with improved safety features such as arc fault detection or any other integrated system that can prevent overcharging, overloading, short-circuits, reverse polarity and dangerous electric arcs are highly appreciated.
Final Verdict
All aspects considered, we consider our pick the Victron SmartSolar MMPT to be one of the finest solar charge controllers available. Chosen because of its reliability, built-in Bluetooth, intuitive usage and higher than average current output and input voltage, all compounded by an affordable price.
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FAQ’s
Yes, it is possible to use more than one charge controller with one battery bank if a single charge controller is not large or powerful enough to handle the output of your solar panel system. With MPPT charge controllers, this can actually be the best way to connect to your system’s solar arrays.
A very important figure that refers to the maximum amount of voltage that a solar charge controller can handle safely. Knowing the Upper Voltage Limit of your model is extremely important. It can prevent from hooking up the charge controller to too much power which can in turn lead to battery burning and other damage or safety issues.
Connecting AC loads to a charge controller is a big one. Only DC loads should be connected to a charge controller’s output. Also always keep in mind that certain low-voltage appliances must be connected directly to the battery.
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