Solar Charge Controllers are an essential aspect of your solar system. They communicate between your solar panel and battery storage to ensure everything is running smoothly, which will extend the lifespan of your batteries.
The amount of solar charge controller options on the market can feel overwhelming, but there is certain to be a solar controller style that will maximize your entire RV solar power setup
To find the best fit for your RV or DIY van conversion, research past the basics of solar charge controllers of various voltages and sizes to understand what your solar array necessitates.
Besides this you need to ensure that the solar charge controller you choose can work with the type of battery you have, and your solar panel set-up to find the perfect charger for your entire system.
This article will help you understand your choices by exploring the role your solar charge controller will play in your larger solar system and examining the pros and cons of each solar charge controller option (PWM and MPPT).
We’ll analyze common technical features of solar charge controllers and look at some of the best solar chargers on the market to find the perfect system to power up your solar array.
What Are Solar Charge Controllers?
Solar Charge Controllers are voltage regulators that keep your batteries from overcharging. During the day, the controller ensures your deep cycle batteries aren’t being fed too much solar energy, damaging the battery’s internal components.
When the sunlight disappears, the controller makes sure power isn’t running backwards to your solar panels, blocking reverse currents.
It is an essential aspect of your overall solar system. Without a solar charge controller, you risk irreversible damage to your battery and a shorter lifespan for your solar panels.
How Do Solar Charge Controllers Work?
A Solar Charge Controller works as the middleman between your battery system and your solar panels. Your batteries will communicate with your solar charge controller, which will pass that message along to the solar panels.
The energy current flows into the controller’s semiconductor, which opens or closes depending on your battery’s current needs.
Each deep cycle battery has its own voltage capacity and any volts above that work against your battery’s health.
A Charge Controller regulates the voltage acquired from the solar panels and opens or restricts the energy flow from the panels depending on what your battery needs.
They have overload protection, which prevents your battery system from overheating when faced with too much current, and low voltage disconnects to automatically disconnect your battery before the battery over-discharges and damages itself.
Two Main RV Solar Charge Controller Styles
Solar Charge Controllers come in various shapes and sizes that all fulfill different functions and have varying strengths and weaknesses.
No matter what your set-up mandates, You can be sure there is a Solar Charge controller that is a perfect fit for you. Most controllers are split into two different categories:
- Pulse Width Modulation (PWM) Charge Controller
- Maximum Power Point Track (MPPT) Charge controller
The first step towards finding the suitable controller for your rig is understanding these two categories and deciding which one will work for you.
PWM Charge Controllers
Pulse Width Modulation charge controllers work like a heartbeat. Controlled pulses of energy are sent from the solar panel to your battery system instead of a constant flow of energy.
The controller will communicate with your battery to get up-to-date information on what it needs, which affects the beat of the pulsation.
Your fully charged battery doesn’t need a long pulse of energy. A PWM controller can understand when to trickle charge your battery and when to send a more prolonged burst of energy. This makes them highly adept for less energy-intensive situations.
These devices won’t handle much more than a 12v solar panel array, and if you have multiple solar panels in your set-up, you’ll need to ensure they are wired in parallel.
At maximum efficiency, these controller types will be able to convert 75% of your solar panel energy draw into usable battery charge.
MPPT Charge controller
MPPT Controllers can handle larger solar arrays. They are heavily favored by RVers seeking to live in their campervans full time or those expecting to get off-grid for weeks at a time.
In addition to communicating with the battery system to understand what charge level your system needs, MPPT charge controllers can sophisticatedly communicate with your solar panels to find the perfect operating voltage.
This communication with your solar panels is where the MPPT gets its name. The device tracks your solar draw to maximize power, which brings up to 30% more charge than a PWM controller.
MPPT’s also take care of converting your solar panel’s voltage power into an energy format that is more digestible for your battery system.
They can alter the volts into amps, which prevents your system from wasting any energy drawn in by your solar panels.
MPPT’s can convert 96% of your solar draw into usable energy for your vehicle.
What Is Better MPPT Or PWM?
PWM controllers can get a more straightforward job done at a more affordable price point than an MPPT charger, but MPPT controllers are built to handle more extensive setups and are more reliable for long-term use.
If you just have a few lights and fans to power up on weekend trips, you won’t need much more than a PWM controller and a full battery before you head out.
If you have a heavy-duty system or expect to rely on your solar charger for weeks at a time, you should commit to investing the extra money for an MPPT charger.
Multiple solar panel systems are a good indicator that you need the extra oomph provided by an MPPT controller.
If you just want to trickle charge your battery to ensure it’s ready to roll when you are, the efficiency of PWM is all you need.
Any system more significant than two solar panels or 150W’s will have to rely on the more extensive charging capabilities of an MPPT solar charge controller.
How to Select the Best Solar Charge Controller for Your RV
Now that you know the two common types of solar charge controllers, you can start to examine the minute details of each model to decide what your solar array needs and what fluff you can skim off the top.
Before you even begin looking for a controller, you should understand the maximum wattage of your solar panels draw and think about the long-term goals of your system.
If you are just starting on your solar journey but want to upgrade your abilities over time, you should ensure your controller can remain functional when you begin to bring in more solar charges.
Calculate the total amperage draw of your solar panels at peak power. This number will reflect exactly how much energy is brought into your panels when receiving maximum exposure to the sun.
It is essential that you slightly overestimate this energy draw, as you don’t want your solar charge controller to have to constantly strain itself to keep up.
Once you know your solar panel amperage, figure out your battery bank’s maximum voltage.
Whatever your solar panel amps bring in is irrelevant if your battery bank can’t handle more than 80 amps, as your solar charge controller won’t force energy into your battery.
You can have six solar panels drawing in hundreds of amps per hour, but if your battery can’t wield that extra energy, your solar controller will be forced to render that power useless.
A safe bet is to find these two voltage numbers and select a charge controller capable of 25 % more power push than the lower of the two voltages.
If you plan on upgrading your battery system or solar panels in the future, you’ll have to upgrade your solar charge controller, too, so be sure to keep that in mind when making your purchase.
A solar charge controller’s only real job is energy transfer. However, modern technology is flooded with convenient options that will make your solar system better.
Solar charge controllers have received their fair share of upgraded features that make using your solar array easier than ever.
High-tech solar controllers pack in tons of data that reports how efficient your system is harnessing solar energy at every step of the process.
Some of the best controllers include Bluetooth technology that lets you access all of this information at the push of a button.
You’ll be able to understand how much power your solar panel is providing, how much of that energy is reaching the controller, and the volts that make it from the controller to your battery.
Having access to all this information makes it easier to understand which aspects of your system excel and which pieces hold everything back.
A Bluetooth system will also constantly inform you of your battery’s charge level, so you won’t have to spend your days wondering whether or not your battery is nearing critical status.
Manually Adjustable Voltage
Every type of battery has different voltage needs. Most modern batteries are built to work with solar systems, but the specific type of battery you use will ask something different out of your solar charge controller than the others.
To ensure that everything stays on the same page, modern charge controllers sometimes include the ability to manually dictate the type of battery the controller will be charging, allowing your controller to give your battery precisely what it needs.
A simple addition of an On/off switch can add years onto the lifespan of your system.
Most RVers hope to hook their solar panels onto their roof, connect those panels to their battery via a solar charge controller, and not have to deal with things for a while.
Solar panels can’t help themselves from drawing in energy from the sun whenever they feel the rays.
If your solar charge controller can’t be turned on and off, you’ll have to disconnect the fuse from your battery bank every time you want to stop your solar panels from charging your batteries.
Overcharging your system can erode the interior materials of your batteries and eventually destroy your battery’s capabilities.
If you want to save space by putting your battery bank in a hard to reach area, purchasing a charge controller with an on/off switch will save you from having to rummage around amongst your wires every time you plan on leaving the vehicle parked in the sun for a few days.
Many Solar Charge Controller advertisements say all the right things. It’s not always so easy to tell if the product can truly walk the walk.
If you find a product at a low cost compared to other controllers capable of the same outputs, check to see if it is UL-certified.
UL certification is a process conducted by a company called UL, whose sole purpose is to maintain high standards in technological equipment.
Any product that has earned a UL certification can be considered safe from malfunction.
Some cheaply made solar charge controllers produce electrical noise as a byproduct, which can interfere with the frequencies of other electronic devices in your vehicle.
UL certifies that the controllers are safe, efficient, and won’t clog up your airwaves.
Your solar charge controller works as the heartbeat for your entire electrical charge system.
Avoid cheaply made products that make big promises in favor of high-quality chargers with plenty of reviews and warranties included.
5 Best RV Solar Charge Controllers
To help you navigate the complex solar charge controller field, we’ve selected 5 of the best solar charge controllers that all work well in different scenarios.
While these solar charge controllers may fulfill different niches, each one was made with high-quality materials and adequately tested to be recognized as the best options in a field full of choices.
Here are the 5 best solar charge controllers for your RV or camper van conversion:
1: Best Overall: Victron 100/50 Smart Solar MPPT Charge Controller
This best-in-class solar charge controller has provided an excellent combination of price and features to fulfill the needs of most full-time RVers.
Capable of handling multiple solar panel set-ups, this charge controller pumps in 100 volts at a time, ensuring that with a high-quality battery, you can get the most out of your solar panels.
Campers thinking about MPPT technology for their charge controller generally have to ensure at least 15 watts of input voltage in your battery for the power point technology to function correctly.
Victron has assured this product stands out by being able to revive a wholly depleted battery and get it back to full functionality in no time.
To round out their offer, Victron slapped on a five-year warranty to this solar charge controller. Your controller shouldn’t be a purchase you’ll have to make every year.
A 5-year full warranty means you can rest easy for trip after trip, and the advanced functionality in this model ensures you’ll never be more than a sunny day away from a full charge.
2: Best PWM: Renogy Adventurer Li- 30A PWM
If you don’t have the most massive energy demands, you can consider going with a PWM charge controller to save a few bucks.
Renogy’s Adventurer model can charge all types of batteries and communicate to your devices via Bluetooth, a rare feature on PWM controllers.
The controller is designed for easy mounting to the walls of your RV, and a convenient display on the device always allows you to be aware of your battery status.
This PWM is also one of the few PWM controllers that can handle 24V solar systems.
With all these rare features, you’d expect a high price point, but this PWM still screams affordability to be listed as our favorite pulse modulation controller.
Renogy included the self-diagnostic system its more significant controllers are known for to ensure a smooth operation.
3: Best Budget MPPT: Renogy Li 40a MPPT Charge Controller
Picking the right controller to pair with your solar panels is an essential aspect of your solar array.
While many budget MPPT’s cut a few corners to save money, Renogy’s 40 AMP controller is a high-quality option at an affordable price point.
While the overall amperage rating is lower than most other models, if you don’t need more than 40 amps of power draw at once, this option will get the job done.
Renogy’s entire company surrounds solar power, and this solar charge controller is one of the company’s flagship offerings.
The package ships with a Bluetooth connection and temperature sensor to keep things healthy.
The controller keeps everything charged and protects your battery against reverse polarity, short-circuiting, and overload.
The self-diagnosing product will protect itself from breakdown, and a die-cast aluminum exterior shields your investment for years to come.
4: Best High End: MidNite Solar Classic 150 MPPT Charge Controller
There’s a reason more people trust this Charge Controller than most other options on the market.
RVers willing to spare no expense in their solar charge system will find Midnite’s Solar Classic to be an excellent high-class option.
Dubbed the most advanced solar charge controller on the market, this bad boy can power 72-volt battery banks and even harness wind energy.
Built in ground fault and arc fault protection goes further than other models to ensure your controller will last for decades.
The device packs in extensive data collection, 96 amps of current, and 150 operating voltage security to provide everything you need in a solar charge controller.
If there is a feature you want in your controller, chances are built into the MidNite Solar Classic.
5: Best Budget PWM: ALLPOWERS 20A Solar Charger Controller
If you aren’t looking for much more than a trickle charge while the battery sits waiting for your next trip, you don’t need anything more than this AllPowers Solar Charger Controller.
The incredible priceBuilt-in point saves you money, and the display system offers USB ports as well as up-to-date battery information.
While this device can’t handle most larger or even medium-sized jobs, it still has the functionality to charge a coach battery slowly and is more than enough to power your fans and the lights for the weekend.
It’s protected from over-currents and short circuits, and the easy-to-use features allow you to plug in the solar charger and be on your way.
When Do I Need an RV Solar Charge Controller?
You will need a solar charge controller whenever you have a solar panel trying to charge your coach battery.
Solar panels have no control over the voltages they draw in. They are simply hungry for the energy of the sun, and if the panels connect to the sun’s rays, they will send volts to your battery if it needs them or not.
A solar charge controller prevents the random bursts of voltages from heading straight to your battery and cleans up the energy to something usable by your battery.
If you try to charge your battery without this middleman, it will quickly lead to permanent battery damage.
What size Solar Charge Controller do I need?
Anyone looking to simply trickle charge their coach battery won’t need a solar charge controller that is larger than 20 amp max current.
If you want to live off your solar set-up but don’t have any fancy electronics that need charging, a 100 amp controller will provide energy as long as the sun is out. Larger set-ups should depend on at least 150 amps.
Shopping for your Solar Charge Controller should be the final step when choosing your solar array.
This is because determining which size Solar Charge Controller you need depends on what your solar panels are capable of and how many volts your battery bank can comprehend.
Figure out how many solar panels will be in your set-up and how many total watts those solar panels can produce.
Once you know this information, you can decide what size Solar Charge Controller you need.
Do You Always Need A Solar Charge Controller?
The short answer is yes, although there are rare low-energy cases where the device is not necessary.
You may be able to trickle charge your battery without a solar charge controller if your total solar panel output is less than 5 watts.
Any half-decent solar panel for RV systems will churn out many more watts than that.
To calculate whether or not you need a solar charge controller, compare the wattage of your panels with your battery amp-hours.
If your panel is at three or more watts per 50 battery amp-hours, you will need a Solar Charge Controller.
Can You Use More Than One Charge Controller?
To meet the energy demands of large systems, you can use two MPPT or PWM controllers in parallel.
Two controllers can help optimize your power output, as long as both the controllers are the same type.
You can’t use a PWM controller with an MPPT controller, but two of either variety can lead to increased efficiency out of your solar system.
What Should You Expect to Pay for Your Controller?
Generally speaking, the price range of Solar Charge Controllers depends on the amount of power they produce.
You can find a 20 AMP PWM solar charge controller for 20$, or you could invest in a high-end MPPT controller for 700$.
You can expect to find a high-quality solar charge controller capable of handling most mediocre solar arrays for 150$.
Now, It’s Up to You
We’ve explored many different facets of these high-tech solar devices. Solar Charge Controllers can do different things and don’t have to be hefty investments.
Modern solar panels soak up hundreds of kilowatts of energy every hour. All that raw juice needs to be converted into something healthy enough for your battery to digest without damage.
Solar Charge Controllers are the mainframe of your electric system. They act as the glue that connects your solar panel to your battery system and ensures that everything in your electric supply stays happy and healthy.
Figure out your solar demand, and let your personal necessity dictate how you look at solar charge controllers.