Best Solar Charge Controller For RV: Maintaining Your RV Battery Life

If you travel full-time and/or prefer boondocking without access to electrical hookups, solar energy would be the logical option, plus it’s green, sustainable and affordable in the long run too. If you own solar panels, you should definitely invest in the best solar charge controller for RV to simultaneously ensure peak performance from your panels and also protect your battery bank. 

A huge shortcoming of using solar energy is that the amount of power you get on a particular day depends heavily on the amount of direct sunlight, which fluctuates between seasons and locations. When a solar panel is directly connected to the battery, the battery would be prone to damages stemming from both too much or too little sunlight. An RV solar charge controller would regulate the current and voltage coming from solar panels to your batteries, thus protecting the batteries for optimal operation and lifespan.

If you know one thing or two about RV life, you’d know that when it comes to any device related to powering, there will be important technical specifications that you must pay attention to. If you know your stuff, dive right into our delicious handpicked list of the very best solar charge controller for RV to buy in 2022. Or if you don’t know what you’re after, this article will teach you everything you need to know, including how an RV solar charge controller works, the different types, crucial buying criteria, leading brands, installation and wiring tips, and much more.

Solar Charge Controllers Comparison Chart

	Product's name	Price	Specifications	More Info
	Renogy 10A 12V/24V PWM Postive Ground Solar Charge Controller Regulator...	$17.99	Capacity: 10 Amperes Dimensions: 4.7 x 3.0 x 1.1 Inches Weight: 0.3 Pounds Intelligent protection LCD display	See Latest Price
	WindyNation P30L LCD 30A PWM Solar Panel Regulator Charge Controller with...	$43.99	Capacity: 20 Amperes Dimensions: 6.3 x 3.5 x 1.5 Inches Weight: 0.5 Pounds Automatic lighting control Mounting holes	See Latest Price
	ALLPOWERS 20A Solar Charger Controller Solar Panel Battery Intelligent...	$17.99	Capacity: 20 Amperes Dimensions: 5.6 x 3.1 x 1.6 Inches Weight: 0.4 Pounds Built-in USB ports Industrial-grade microprocessor	See Latest Price
	Victron SmartSolar Charge Controller with Built-in Bluetooth – MPPT 75/15...	$118.10	Capacity: 15 Amperes Dimensions: 4.4 x 3.9 x 1.5 Inches Weight: 1.2 Pounds LED indicators Programmable	See Latest Price
	Victron SmartSolar MPPT 100/50 Charge Controller	$323.85	Capacity: 50 Amperes Dimensions: 7.2 x 5.1 x 2.7 Inches Weight: 2.9 Pounds Integrated Bluetooth connectivity For 12V and 24V batteries	See Latest Price
	EPEVER MPPT Solar Charge Controller 30A 12V 24V Auto, Solar Charge...	$138.89	Capacity: 30 Amperes Dimensions: 9.0 x 6.4 x 2.2 Inches Weight: 2.8 Pounds Multiple load control modes Wide operating voltage	See Latest Price
	Go Power! By Valterra GP-PWM-30-UL Solar Controller - 30A, Digital , Black	$142.37	Capacity: 30 Amperes Dimensions: 7.5 x 4.2 x 1.4 Inches Weight: 0.7 Pounds Digital display Maximum Power Boost Technology (MPBT)	See Latest Price
	MidNite Solar CLASSIC 150 MPPT Charge Controller, 150 Operating Voltage,...	$699.99	Capacity: 80 – 96 Amperes Dimensions: 14.9 x 6.0 x 4.0 Inches Weight: 11.5 Pounds ETL listed Arc fault and ground fault	See Latest Price
	EPEVER MPPT Solar Charge Controller 30A Tracer3210AN + Remote Meter...	$136.99	Capacity: 20 Amperes Dimensions: 8.7 x 6.1 x 2.0 Inches Weight: 2.1 Pounds Auto voltage detection Diverse loads	See Latest Price
	OUTBACK POWER 80AH MPPT Controller	$478.00	Capacity: 80 Amperes Dimensions: 16.2 x 5.7 x 4.5 Inches Weight: 12.2 Pounds Active cooling Data logging	See Latest Price
	GHB 20A 12V 24V Solar Charge Controller Auto Switch LCD Solar Panel Battery...	$$$$	Capacity: 20 Amperes Dimensions: 5.1 x 3.9 x 1.2 Inches Weight: 0.3 Pounds Energy-saving backlight All-around protection	See Latest Price
	HQST PWM Solar Charge Controller,40A Flush Mount Solar Panel Battery...	$$$$	Capacity: 10 Amperes Dimensions: 7.4 x 3.8 x 2.1 Inches Weight: 0.9 Pounds Automatic temperature compensation Current-limiting charging	See Latest Price

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RV Solar Charge Controller Basics

What is a solar charge controller? 

Solar panels cannot directly charge your RV’s battery using energy from sunlight. You need to use a solar charge controller to convert this energy from the sun into usable energy for your batteries.

An RV solar charge controller is a device that monitors and regulates the flow of electricity (the current and voltage) coming from your solar panel system to the batteries for optimal charging. Charge controllers can also allow for smart charging cycles and thus higher charging efficiency . They do this by keeping track of roughly how much power is currently stored in the battery and therefore adjust to the appropriate charging amperage. 

In short, you can say an RV solar charge controller is the heart of your solar energy system as they will make sure everything functions efficiently and correctly. They can be seen as insurance for charging your RV’s battery using solar energy. You’ll see why in a minute.

The major role of a solar charge controller for RVs is critical, that is ensuring your battery is not overcharged. Overcharging at a high voltage results in overheating, which is detrimental to the battery’s efficiency in holding a charge as well as its lifespan. 

We’ll explain in more detail but in short, if you’re using solar energy to top off your RV’s battery, then without the best solar charge controller for RV, the batteries will not be charged properly. This might cause damages to the battery pack or will shorten battery life.

So it is quite apparent that a solar charge controller for RV is not just something nice to have, it’s a must-have. Seasoned and full-time campers will tell you that you must not attach a solar panel directly to a battery pack without a reliable solar charge controller (unless your solar system is small).

Why do we need a solar charge controller for RVs?

Why is a solar charge controller for RV a must-have? This is due to the nature of solar energy. The power provided by sunlight can vary tremendously based on season, time of day as well as your location or your altitude. As a result, there will be periods when your solar panels receive too little sunlight so there’s not enough energy to charge your RV’s battery to a full charge.

And there will be other times where there’s too much sunlight, and your solar panels will work at their peak performance. Either way, too little or too much sun power can cause damage to your RV’s battery.

Preventing Overcharge & Undercharge

Specifically, very little sunlight or a total lack of solar energy would lead to an extremely low charge, which is not desirable for your battery’s lifespan. Meanwhile, a sudden surge and an excessive amount of power can overcharge your battery at a high voltage and thus overheating it, which could also reduce its lifespan. It’s worth noting here that each type of battery for recreational vehicles requires a different level of amperage at the three distinct charging stages for optimal charging and lifespan.

When a solar panel is directly connected to the battery, it can be overcharged. A 12-volt solar panel can produce an output of 21 volts during peak sunlight, while your 12-volt battery should be charged to a maximum voltage of only 14.4 volts.

To avoid the common scenarios of varying sun energy, a solar charge controller will sit between your battery and solar panels to control the energy your battery receives. With the best solar charge controller for RV, the likelihood of batteries sustaining damages due to unstable current, low discharge rate, overcharging and overheating would be minimized. 

Blocking Reverse Current

Solar panels work by pumping current through your battery in one direction. At night, the panels may pass a bit of current in the reverse direction, causing a slight discharge from the battery. (Our term “battery” represents either a single battery or bank of batteries.) The potential loss is minor, but it is easy to prevent. Some types of wind and hydro generators also draw reverse current when they stop (most do not except under fault conditions).

In most controllers, charge current passes through a semiconductor (a transistor) which acts like a valve to control the current. It is called a “semiconductor” because it passes current only in one direction. It prevents reverse current without any extra effort or cost.

How do they work?

During the process of charging your RV’s batteries, a solar charge controller will typically go through three distinct charging stages:

Bulk Charge: 

The first stage is characterized by a faster charge rate to bring voltage up as quickly as possible, so that a depleted battery will receive high current to quickly replenish. The battery will be recharged up to 80% of its capacity.

This stage uses 100% of the sun power available to your solar panels to charge your batteries until the absorption voltage is reached, which in most cases will be between 14.4 and 14.6 volts.

Absorption Charge: 

After it reaches the set absorption voltage, the solar charge controller  will switch to the absorption stage of the charging process. During this stage, the battery will continue to be recharged to its full state of charge with a slower charge rate and the charge controller will maintain the absorption voltage for a set period. Both the voltage and length of time will depend on each specific solar charge controller.

Float Charge: 

Once the absorption stage is done, your RV’s battery should be almost fully charged. After full capacity is reached, the batteries will receive a trickle charge to maintain this full state of charge. In other words, the charge rate in the float stage is equal to the battery’s natural self-discharge rate.

The charge controller will switch to a lower voltage, which should be between 13.2 to 13.7 volts depending on the specific model, and maintain this low voltage for the rest of the solar day. This lesser charge makes up for the natural self-discharge and also makes sure the batteries will not be overcharged and overheated. The low voltage also ensures that the battery acid doesn’t boil off. 

If there happens to be an excessive load on your batteries and the controller can’t maintain the charge level during this stage to keep the battery fully charged, it might switch back to the bulk charge model to ensure the batteries is recharged to 100% and stays there.

So a solar charge controller’s three-stage charging ensures that the battery is charged in an efficient way and maintains a full charge while minimizing water loss and stress.

Equalization Charge: 

Every solar charge controller goes through these three charging stages are what every charge controller to ensure your RV’s batteries are fully charged. However, do note that there’s a fourth mode called equalizing charge. 

It is a periodical controlled overcharged and this is desired as a means of battery maintenance. You can do this by applying a controlled overcharge once every 30-90 days, or whenever individual batteries are imbalanced, that is they are reading a different voltage. 

This mode charges the batteries at a voltage between 14.8 and 15.5 volts depending on the model, which means it will be overcharging the batteries and gasing the battery’s cells. This results in all the battery bank’s cells having the same charge, thus the process is called “equalization”.

This process will occur every four weeks, but some devices will automatically switch to equalization mode when the battery bank voltage dips below a specific level, typically somewhere between 10 and 12.1 volts, depending on the manufacturer.

While this is not required for sealed deep cycle batteries, flooded lead acid batteries should be equalized occasionally to make sure each cell is equally charged. But there are some AGM and gel lead-acid battery manufacturers recommend doing this as maintenance for their batteries as well.

The process for an equalizing controlled overcharge is as follows:

• Check water level before initiating an equalize charge.
• Turn off any loads.
• Set your charger at the Equalize voltage specified in your battery manual.
• Start the Equalize charge. Gassing and bubbling is normal during this process.
• Stop charging and take specific gravity readings every hour. The EQ process is complete when the specific gravity stops rising.

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Types of Solar Charge Controller

The number of solar charge controllers for recreational vehicles certainly seem overwhelming but all models could be split into three types: Shunt, PWM and MPPT 

• Shunt Charge Controllers (On/Off): With limited functions and features, shunt charge controllers tend to be considered as the most basic choices for solar systems. In use, models of the type just stop the charging current when the charge of batteries reaches a particular level. The simplicity of shunt charge controllers let them operate in variable conditions with relative ease. 
• PWM Charge Controllers (Pulse Width Modulation): Able to bring batteries to max capacity and maintain the charge level with trickle charges, PWM charge controllers excel at keeping battery banks topped-off. Because of that, models of the type earn positive remarks from enthusiasts of RVing that travel on a regular basis. 
• MPPT Charge Controllers (Maximum Power Point Tracking): Thanks to the outstanding efficiency and ability to regulate high currents, MPPT charge controllers give a good account of themselves in sophisticated and big setups. Moreover, since they come equipped with plenty of built-in safety precautions, models of the type have reassuring operating records. 

Best Solar Charge Controller Reviews

Due to preferences, different RVers think of different models once it comes to the best solar charge controller for RV. Still, in the case that you wish to get your money’s worth, you should check out the models below.

Which unit would make the best solar charge controller for RV in your circumstances depends on a variety of factors, including your budget, how often you camp, whether you travel year round or typically camp in the summer when there’s more direct sunlight, and the size of your solar system. 

Therefore, if you don’t know what to look for in the solar panel controllers for RV, skip to the next section to learn more about the most important buying criteria. If you know your stuff, dive right into our delicious handpicked list of the very best solar charge controller for RV to buy in 2022.

These models are selected for their well-roundedness based on specifications, plus for having  proven track records based on in-depth solar charge controllers reviews by seasoned campers around the world. There is something for every camper here, regardless of your budget or capacity requirements.

1. Renogy Wanderer 10 Amp 12V/24V PWM – Best Of The Best 

Why This Is The Best: 

Utilizing various innovations, Renogy Wanderer (RNG-CTRL-WND10) is a solid model that works superbly in an assortment of arrangements. With an LCD display, Wanderer (RNG-CTRL-WND10) allows enthusiasts of RVing to grasp the charging status through a glance. In addition, since the charge controller made by Renogy packs intelligent protection, it’s well-shielded against threats such as overcharging, reverse polarity, short-circuit, … Because of that,  regarding all-around protection, Renogy Wanderer (RNG-CTRL-WND10) is undoubtedly the best solar charge controller for RV at its price range. 

Thanks to the lightweight body, the charge controller of Renogy is convenient to handle and could be set up in a blink of an eye. Wanderer (RNG-CTRL-WND10) occupies little space as well so finding a fitting spot for it is child’s play. In terms of compatibility, Wanderer (RNG-CTRL-WND10) of Renogy is able to accommodate many types of RV batteries including sealed, gel, flooded and lithium. Hence, if your battery bank consists of more than one type of battery, the Renogy charge controller should suit you. 

Interestingly, Renogy Wanderer (RNG-CTRL-WND10) comes equipped with a communication port for Bluetooth module. That means it’s possible to remotely monitor Wanderer (RNG-CTRL-WND10) and apply changes to its parameters if necessary. 

To start off, I’m no expert. But I’m working with what my 5th wheel came with (single lead acid battery) and a portable solar panel system that came with it’s own charge controller for standard lead acid batteries only. First time out doing any serious boondocking I knew (which was not a surprise) I needed more. More battery bank, more solar panel wattage, and a more robust and versatile charge controller. So my next step was to purchase more robust batteries for increased amp hour storage, and a charge controller compatible with said batteries. The installation of this charge controller was straight forward. I was able to adapt my current solar panels to use it, and it does a great job (from what I can see) of maintaining my new battery bank. It works with a verity of battery types. So I’m ready if I decide to make another change there. My next step will be upgrading my solar panels. But this controller is capable of handling where ever I go next.

Shared by Roger Wtaylor

2. WindyNation P20L LCD 20A PWM – Editor’s Choice 

Why It’s An Editor’s Choice: 

Dependable and reliable, WindyNation P20L rarely lets RVers down in the course of operation and that earns it compliments from solar charge controllers reviews. Possessing a rated capacity of twenty amperes, the WindyNation charge controller easily handles the regulation requirement of typical solar systems. Moreover, with accessible design and built-in mounting holes, P20L takes a couple of moments to install and secure. That is a big plus for people that have to set up a proper solar charge controller on the go. 

About interface, WindyNation P20L boasts a flush LCD display and adjustment buttons that facilitate supervision and implementation of changes. It’s worth pointing out that P20L integrates a microcontroller for automatic lighting control. As a result, even in low-light conditions, enthusiasts of RVing could get a good view of the interface of the charge controller from WindyNation. P20L of WindyNation is protected from overload, short-circuit, reverse polarity and alike so its operating record is excellent. 

Since P20L is a low-priced model, cost-conscious RVers deem it to be the best solar charge controller for RV on the market. On arrival, the charge controller made by WindyNation is accompanied by a one-year warranty. 

Seems like the best bang for the buck. It’s only been one week and things are going great with it, and I no longer have an extension cord strung out to my camper! It’s hooked to two 145W mono panels and two Trojan 12V deep cycles. 10 AWG from my combiner box, about 8′ long and 8AWG from the controller to the batteries about 4′ long. I’ll be sure to update in the future!

Shared by Mia

3. ALLPOWERS 20A – Editor’s Choice 

Why It’s An Editor’s Choice: 

Designed with functionality in mind, FBA_AP-OT-002-BBLU of All Power regularly gives a good account of itself in use. As it carries an industrial-grade microprocessor, FBA_AP-OT-002-BBLU manages the charging of batteries with outstanding precision and stability. Also, owing to the improved heat dissipation, the charge controller from All Power maintains the operating temperature at reasonable levels. Unsurprisingly, All Power FBA_AP-OT-002-BBLU is prized by RVing enthusiasts that plan to hit the road in the summer. 

The All Power solar panel controller for RV charges the batteries in multiple stages, thus, it minimizes power loss and extends the longevity of cells. That is why with FBA_AP-OT-002-BBLU onboard, the replacement interval of batteries lengthen noticeably. Besides the batteries, All Power FBA_AP-OT-002-BBLU could provide charge to electronic devices using its built-in USB ports. So once it comes to adaptability, the charge controller made by All Power is usually deemed to be the best solar charge controller for RV. 

For maintenance,  FBA_AP-OT-002-BBLU just needs simple care to remain operational which is advantageous. If you grab All Power FBA_AP-OT-002-BBLU, you can spend more time enjoying the outdoors and less time worrying about your solar charge controller. 

4. Victron Energy BlueSolar

Why We Love It: 

As a highly capable MPPT charge controller, Victron Energy BlueSolar is appreciated by RVers who wish to get the most out of their solar systems. With the ability to accelerate the energy harvest rate, the charge controller made by Victron Energy shortens the time it takes to fully charge batteries. Therefore, BlueSolar is the best MPPT charge controller for recreational vehicles that have high power consumption and large battery banks. Additionally, featuring modern battery management, Victron Energy BlueSolar preserves the integrity of the batteries and increases lifespans of the cells. 

BlueSolar contains catchy LED indicators and its case list explanations for individual lights too so determining charging status is essentially a walk in the park. In times of need, RVing enthusiasts could attach a Bluetooth dongle to the Victron Energy charge controller and pair it with smartphones for remote monitoring. As a result, people don’t have to stay next to Victron Energy BlueSolar at all times in order to keep an eye on things. Last but not least, since BlueSolar is proof against short-circuit, its level of safety is regarded to be sublime. 

To reassure potential users, Victron Energy willingly offers everyone that picks up its charge controller a five-year manufacturer warranty. In the case that you happen to seek a sound insurance policy, you have to add BlueSolar to your shortlist. 

After a month of use, this controller seems to be exactly as advertised. I installed this on a Class C motorhome with two 50 watt Renogy solar panels installed in series to have the combined output at double voltage of a single panel for better efficiency. I also like the Bluetooth interface. That saved having to install an extra-cost remote monitor/control unit. Installation was straightforward and the instructions were adequate. After the solar input was connected, I immediately was getting over 50 watts in early day cloudy conditions. I installed the Victron app on my Android phone and got the Bluetooth connection established and saw the parameters for solar input and battery state. I set up the equalize cycle and put the RV in storage. After a couple of weekly checks, the two house batteries were fully charged in float mode. The history readout on the app showed that input was running 42-43 volts and over 90 watts on occasion. I am very satisfied with my selection of this unit. Also, it is quite compact and light weight. The only thing better might be a battery temperature input, but for my needs, not critical.

Shared by Amazon Customer

5. Victron Energy SmartSolar

Why We Love It: 

Interested in the idea behind BlueSolar of Victron Energy but want more capacity and capabilities? Then it’s strongly recommended that you take a close look at Victron Energy SmartSolar. At fifty amperes, the capacity of SmartSolar permits it to receive and control the sizable flow of electricity from extensive solar systems with relative ease. Packing enhanced monitoring and harvesting, the charge controller of Victron Energy also optimizes the charging rate of batteries as light intensity changes throughout the day. 

With its small build, Victron Energy SmartSolar smoothly squeezes into narrow corners which help enthusiasts of RVing conserve interior space. The Victron Energy charge controller is light as well, hence, moving it into position is going to be a cinch. By checking LED indicators on SmartSolar, it’s a breeze to stay up to date about the progress of charging. Aside from that, as Victron Energy SmartSolar possesses integrated Bluetooth connectivity, it could readily pair with a lot of mobile devices and eliminate the need to stay nearby to supervise. 

Compared to standard charge controllers for solar panels on recreational vehicles, SmartSolar of Victron Energy is indeed a bit expensive. Still, the values of SmartSolar match its price tag and Victron Energy back its controller with a top-notch warranty. 

I bought this for my first solar install– 600 watts– on a cargo trailer converted to an RV in spring of 2018. This unit was so painless and easy to configure and use that I purchased a second Victron as part of an “identical twin” solar setup I’ve now installed in my home to power my computer stuff and TV. (Yes, this review was written on solar power.) It’s ludicrously easy! My only quibbles– not enough for me to take off a star– center around the smartphone app. (In my case it’s the Apple version.) It’s a good, well-organized app overall, but… First, if you have more than one controller in more than one location as I do, you have to close the app entirely between checking them or else the software seems to become confused and won’t register the second controller. Also, I wish the smartphone could “remember” at least the last data it dowloaded, so that I could store the controller data from the trailer’s array and look at it later. As things are now I have to stand outside in the hot sun and study the array’s past performance, etc on the spot, as it’s only available while the bluetooth is actually connected.

Shared by Phil Geusz

6. Epever Tracer 3210AN

Why We Love It: 

Being engineered with advanced function and peak efficiency, Epever Tracer 3210AN excels at maximizing power output and reducing energy loss. Furthermore, since the Epever charge controller charges the batteries in four stages (bulk, boost, float, and equalization), it keeps the battery bank in top shape. Because of that, to economically minded RVers with tight wallets, Tracer 3210AN is the best solar charge controller for RV. Besides that, Epever Tracer 3210AN works well with typical battery types from gel to lead so its compatibility is marvelous. 

By incorporating protection against short-circuit, overcharging, reverse polarity and similar issues, Tracer 3210AN outperforms traditional solar panel controllers for RV in terms of safety. With the controller of Epever around, enthusiasts of  RVing don’t have to worry too much about their solar systems. As for the user interface, Epever Tracer 3210AN contains a functional LCD display that shows charging status and key data. Thus, supervising and manipulating the operation of Tracer 3210AN is by all accounts a snap. 

The charge controller made by Epever makes use of aluminum in the construction, therefore, it’s both portable and durable. As its setup process is fairly straightforward, Tracer 3210AN could be installed in just a flash and that is nice. 

7. Go Power GP-PWM-30-UL

Why We Love It: 

Despite its plain appearance, Go Power GP-PWM-30-UL rarely lets enthusiasts of RVing down in the course of operation. Boasting Maximum Power Boost Technology (MPBT), GP-PWM-30-UL allows people to increase charging rate and top off batteries at the end of daylight hours. Also, as the Go Power controller packs a no-nonsense digital display, it’s a breeze to determine charging current, system voltage and battery capacity. Based on the needs of RVers, GP-PWM-30-UL of Go Power is able to charge two battery banks simultaneously.

Put together for common batteries, the controller made by Go Power supports three types of batteries: flooded, AGM and gel. That is why GP-PWM-30-UL is compatible with many solar systems on campers viewed in a positive light by numerous RV solar controller reviews. For installation, Go Power GP-PWM-30-UL features great handling which means setting it up is a piece of cake. Naturally, once it comes to ease of installation, countless RVers consider the controller from Go Power to be the best solar charge controller for RV. 

As proof of confidence, Go Power backs GP-PWM-30-U with a solid five-year warranty that covers manufacturing defects. So if your GP-PWM-30-UL of Go Power fails due to production flaws within the warranty period, you could claim yourself a free replacement. 

8. MidNite Classic 150

Why We Love It: 

In the case that you have a big-sized solar system and have to regulate lots of power, you would come to like MidNite Classic 150. The rated capacity of the controller from MidNite varies between eighty and ninety six amperes depending on the working temperature. Needless to say, Classic 150 is a splendid addition to broad RV solar systems as well as those with expandability potential. Moreover, possessing arc fault and ground fault, Classic 150 of MidNite is safe to use in a wide range of environments. 

Classic 150 comes with a user-friendly interface that consists of a display and buttons so it’s easy to operate.  Since the controller of MidNite takes up negligible amounts of space, you don’t have to leave other things behind in order to accommodate it. It’s noteworthy that aside from solar, MidNite Classic 150 could be put to good use in wind and hydro systems. Hence, Classic 150 is compatible with plenty of energy conversion systems used by enthusiasts of RVing. 

For maintenance, the MidNite controller needs rather little attention from owners of recreational vehicles and that certainly saves precious time. Classic 150 is backed with a five-year warranty too so its users have something to count on if things go wrong all of a sudden. 

9. Epever Tracer 2210AN 

Why We Love It: 

Basic and practical, Epever Tracer 2210AN works like a charm in multiple surroundings and its maintenance is a cakewalk too. Since it integrates auto voltage detection, Tracer 2210AN could determine the ideal charging current for particular batteries on its own. That is why with the charge controller made by Epever, enthusiasts of RVing don’t have to manually set up the current prior to charging. Finally, featuring short-circuit, reverse polarity, over-voltage and other protections, Tracer 2210AN of Epever rarely experiences troubles in use. 

Carrying a robust LCD display, the Epever charge controller permits owners of recreational vehicles to monitor the charging of batteries and make changes at will. Interestingly, Tracer 2210AN provides real-time energy statistics recording so RVers have no trouble gathering data for energy conversion analyses. Epever Tracer 2210AN is sold with pretty much everything included, thus, there is no need to pick up extra hardware. Usually, with standard tools, people need only minutes to get the MPPT solar charge controller of Epever up and running. 

Tracer 2210AN  is sold at a price that suits the budgets of ordinary enthusiasts of RVing, its purchase would have impacts on your upcoming spendings. Unsurprisingly, Epever Tracer 2210AN is called by many people the best MPPT charge controller for the money regarding cost values. 

10. Outback Flexmax 80

Why We Love It: 

Thanks to active cooling and intelligent thermal management, Outback Flexmax 80 dissipates heat effectively and efficiently in the course of operation. Therefore, the heat tolerance of the charge controller from Outback is superior to that of normal models on the market. For RVing enthusiasts that routinely experience high temperatures while traveling and worry about equipment overheating, Flexmax 80 is a must-have. In addition to that, Flexmax 80 of Outback happens to utilize a compact design so its presence hardly requires space consideration. 

Flexmax 80 is engineered with the latest MPPT algorithm that lets it increase the power out of solar systems on recreational vehicles by roughly one third. As a result, the charge controller made by Outback substantially shortens the charging time of batteries and that is handy in an assortment of situations. About compatibility, Outback Flexmax 80 supports batteries of variable types and if needed, it could even reduce the voltage of coming electricity for low-voltage batteries. So Flexmax 80 is well-suited for battery banks of rigs. 

In terms of ease of use, Outback Flexmax 80 employs a fantastic display that keeps RVers up-to-date about the essential aspects of charging progress. It’s possible to access data of the Outback charge controller within the last one hundred and eighty days too. 

11. GHB Solar Charge Controller

Why We Love It: 

Created with convenience in mind, GHB Solar Charge Controller is highly sought after by enthusiasts of RVing that travel frequently. Through the content-rich LCD display of the charge controller from GHB, people could supervise parameters of the charging progress. Packing energy-saving backlight, the display of GHB Solar Charge Controller also remains viewable as ambient lighting changes over time. Because of that, with the charge controller made by GHB, monitoring the charging of batteries is a piece of cake. 

 GHB Solar Charge Controller incorporates a battery indicator so you should be able to notice issues with battery connections quickly. In use, the battery icon of the charge controller of GHB flashes at a fast rate as the batteries receive charges and slow down when the max capacity is reached. Owing to the built-in USB ports,  GHB Solar Charge Controller may charge battery banks of recreational vehicles as well as electronic devices of RVers. Hence, by grabbing the GHB unit, you would have an easy time addressing charging needs. 

As for safety, GHB Solar Charge Controller is equipped with all-around protections: under-voltage, short-circuit, reserve polarity, lighting, … So compared to classic charge controllers for RV solar panels on the market, the model of GHB is quite safe. 

12. HQST HCC10MPPT-G1

Why We Love It:

Purposely developed for energy conversion systems that involve solar panels, HQST HCC10MPPT-G1 possesses nearly everything that RVers expect from a solar charge controller. Using innovative MPPT technology, HCC10MPPT-G1 maximizes conversion rate and increases the power output. Furthermore, with internal and external temperature sensors, the charge controller made by HQST automatically applies compensations in times of need and adjusts the charging current. That is why owners of HQST HCC10MPPT-G1 hardly need to micromanage the charging of their RV battery banks. 

Since the charge controller of HQST charges the batteries in multiple stages, it reduces energy loss and protects the cells. Thus, by including HCC10MPPT-G1 in the solar systems, owners of recreational vehicles could cut down the expenses that go into the battery replacements. For installation, HQST HCC10MPPT-G1 features impressive portability so its setup process lasts mere minutes and there is really no need for special tools. The HQST charge controller contains a mounting holes tool so keeping it secured is no sweat. 

Regarding compatibility, HCC10MPPT-G1 works with sealed, gel and flooded batteries which allow it to match most battery banks. The HQST charge controller recognizes voltage on its own so you don’t have to reprogram it following battery swap. 

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Best Solar Charge Controller Buyer’s Guide

Size or Capacity

The first crucial factor to consider is you’ll need a charge controller that has enough capacity to handle the amount of current and power created by your RV’s solar system. Solar charge controllers for RV are rated based on the solar system’s voltage and your solar array’s current (amps). 

Of course, power always comes at a price. Therefore, the higher the power rating of a solar charge controller, that is the larger its capacity, the more expensive the unit will be.

You can find the maximum amount of amps your solar panels can output, usually expressed as “ISC” or “Short Circuit Current” on a label on the back of each panel. Since most RV solar panels are wired in parallel, the amperage from every panel is added together to work out the maximum amount of amps output. 

1. Amp Rating

The first thing you’ll want to consider when seeking the best solar charge controller for RV is the amp rating. This rating tells you the highest amperage the controller can output to the batteries. The best solar charge controllers will even let you change charging capacities to match different types of batteries. 

A typical solar charge controller can provide a charge between 10 and 90 amperes to the battery banks. As a general rule of thumb, if you have a 12-volt battery bank, you would need at least 7.5 amps for every 100 wattages of solar.

For example, if you have a 300W panel setup, you will need a charge controller with an ampere rating of 22.5A. Do note that you should not cut it close (always be extra careful when it comes to your battery), so round 22.5A up and get a charge controller with 30A rating, which is a common size for these devices. Also, 30A is big enough so that you can add another 100W worth of panels later on if you find you’re not getting as much sun as you were expecting.

Let’s go through another example. If you have a solar system with a voltage of 12 and an amperage rating of 14, you would need a controller with at least 14 amps. A solar charge controller with anything lower, say 10 amp rating, wouldn’t be optimal. Your panels would create 14 amps in total and the controller can only output 10 amps to your battery. This means 4 amps would end up being lost. 

The best practice is to choose a solar charge controller with a rating that’s 25% higher than your solar panel’s peak power to act as a safety cushion. In our example, this would bring the minimum amps rating for your ideal charge controller up to 17.5 amps. As always, round up, so you should purchase a 12-volt solar charge controller with 20 amp rating (round up to the next common size from 17.5 amp).

It’s worth noting that getting a charge controller with too high an amperage rating will have no negative effects other than you having to pay more. Professionals and seasoned RVers actually often recommend that you purchase a controller with some extra amps so you can comfortably add more panels in the future without much fuss. 

In addition, there will likely be times when your solar panels will produce more than their output rating. The extra 25% cushion will ensure you can take advantage of these circumstances. This cushion also makes sure that the controller will run more reliably and run cooler, thus will also last longer. 

2. Voltage 

For reference, common charge controllers for RV feature a voltage of 12 volts, 24 volts and 48 volts. But you might see charge controllers with voltage ratings anywhere between 6 and 60 volts.

* Note on capacity: When one charge controller can’t handle the output of your sizable solar array, you can use multiple RV solar charge controllers so they can all work on the same battery bank. 

These controllers will connect through communication cables, which will help ensure there aren’t any issues. The wires would connect these charge controllers in a parallel fashion across the battery bank.

Features

If you come across several charge controllers that have comparable specs and have a hard time making up your mind, then it’s a good idea to take a close look at the miscellaneous and see which model offers better value for money. For instance, the best solar charge controller would come with the following which would make your camping experience a bit easier and safer: 

1. On/off switch

A solar charge controller with an on/off switch would keep your charge controller independent with your solar systems. You can use the switch to shut down everything without having to remove the fuse or hit the breaker.

2. Adjustable charging voltage point

As noted above, each of the three charging stages of a battery requires different charging voltage for optimal charging. Which also means you should never use a controller that is not intended for your battery type.

Models with adjustable charging voltage points  have a means to select the type of battery it is regulating. This will allow you to adjust the voltage during the charging process based on the type of battery: AGM, flooded lead-acid, or gel. 

If you use more than one type of battery in your RV, the feature to adjust charging voltage points will come in very handy and will keep all of your battery banks in good shape for a long time. 

It should be noted that sealed batteries need to be regulated to a slightly lower voltage than flooded batteries or they will dry out and be ruined. If you’re confused by what voltage is right for your battery, you can always contact the battery manufacturer to get the info you need. 

3. Battery temperature sensor

The best solar charge controller for RV will usually have a feature called battery temperature sensor. This feature will ensure the batteries don’t become undercharged or overcharged, both of which will ultimately damage your battery.

Batteries get overheated too quickly during a fast charge at high voltages and they may lose a lot of distilled water or their plates would become heavily sulfated. To avoid such overheating, a charge controller with temperature sensors would adjust the charging set points to match the temperature of your batteries for safer charging.

The ideal voltage set points for an RV solar charge controller vary with a battery’s temperature. The best solar charge controller for RV would have a feature called “temperature compensation.” When the charge controller senses a low battery temperature, it will raise the set points. In contrast, when the battery is cool, it will reduce the charging voltage. 

If your batteries are exposed to temperature swings greater than about 30° F (17° C), such temperature compensation is essential as a protection against sulfation and excess water loss. The typical temperature compensation for a 12-volt battery is -.03 volt per ° C deviation from the standard 25° C.

High quality charge controllers for RV might also have a built-in temperature sensor. These devices must be mounted in a place where the temperature is close to that of the batteries. More advanced models instead would have a remote temperature probe on a small cable, which should be attached directly to the batteries in order to sense and report battery temperatures to the charge controller.

With information from the temperature sensors, your charge controller will apply necessary compensation as temperature fluctuates to prevent plate sulfation and excess water loss, which are both burdensome for your batteries. 

If you opt for a model that does not offer this feature, an alternative to having automatic temperature compensation is to manually adjust the voltage set points if possible in accordance with the seasons. It may be sufficient to do this only twice a year, in spring and fall before experiencing the significant temperature changes in summer and winter.

4. Overload protection

A circuit is overloaded when the current flowing in it is higher than it can safely handle. Overload problems can cause overheating and can even be a fire hazard. Overload can be caused by a fault in the wiring like a short circuit, or by a faulty appliance like a frozen water pump. 

The best solar charge controller for RV have built-in overload protection, usually with a push-button reset. It should be noted that even with overload protection features, most systems would still require additional protection in the form of fuses or circuit breakers. You should consult the manufacturer and the National Electrical Code for any external fuse or circuit breaker requirements.

If you have a circuit with a wire size for which the safe carrying capacity is less than the overload limit of the solar charge controller, then you must protect that circuit with a fuse or breaker of a suitably lower amp rating. 

5. Dry camp/ Shore power switch

Another handy feature so you would get more bang for your buck is the ability to change the battery’s charging set points between maximum power and standby mode. Maximum power would be the better choice when you prefer to boondock or dry camp away from the RV campgrounds and thus without access to shore power. 

But the standby mode would be the better option if you’re usually plugged into shore power, or when you need to store your RV away in the off season as it will better keep your batteries from natural self-discharging. Therefore, having a switch for conveniently switching between these modes will allow you more freedom to camp however you like, all the while making sure that your battery is well cared for.

6. Displays 

RV solar charge controllers include a variety of possible displays, ranging from a single red light to indicate on-off to digital displays with accurate voltage and current readings. These indicators are important and useful, as a user-friendly display system can indicate the flow of power into and out of the system, the approximate state of charge of your battery, and when various limits like voltage set points or battery temperatures are reached.

7. Amp-hour meter

In addition to a good display system, you might want to spend about US$200 for a separate digital solar charge controller that includes an amp-hour meter if you want complete and accurate monitoring of your battery. The meter will continuously keep track of the energy available in your battery. 

If you have a separate monitor device like these amp-hour meters, then it is not important to get a charge controller that comes with a digital display itself, since even the cheapest amp-hour meter should include a voltmeter as a bare minimum indicator of system function and status.

8. Waterproofness

A solar charge controller for RV can be mounted directly on the rear of the solar panel. As it is exposed to the outdoor elements, you might as well get a  waterproof solar charge controller that can withstand the weather so that it will stay with you for many years to come.

9. Low Voltage Disconnect

Most charge controllers have three sets of terminals: one set goes to the battery, another set goes to the solar panels. And the third set is a load connection and usually says “LOAD” or “LVD”, which stands for low voltage disconnect. 

This low voltage disconnect feature is designed to be a level of battery protection. The controller turns off the load of a system automatically when the load drains the battery bank to a low voltage, thus “low voltage disconnect”. 

The load output is meant to power all of your electrical appliances in your rig through the charge controller. So you’d have the (+) wire run to a DC fuse box that is connected to all these electronics and the (-) wire connects to a bus bar for the return wires of all these electronics.

If the batteries drop below a certain voltage, the solar charge controller will cut power to the fuse box to protect your batteries from being drained further. This prevents your batteries from getting damaged due to frequent deep discharges. Some smart charge controllers will adjust this voltage cutoff if your batteries aren’t getting full charge daily. 

There are three types of low voltage disconnect. One is voltage controlled LVD: When the battery is drained down to a set voltage, the controller disconnects the load within just a few minutes. 

Another type is SOC controlled LVD, which is smarter: The controller considers the battery’s current state of charge and load current to dynamically determine when to switch off the load. Such “considerations” means the controller typically takes longer, about half an hour to switch off the load. 

A third type is emergency LVD, also called undervoltage protection. Emergency LVD is usually triggered due to errors or fault conditions when the battery voltage suddenly drops to an extremely low level. It is thus very fast acting to prevent serious damage to the batteries.

Safety 

Generally, once it comes to electricity, it’s impossible for you to be too careful since a small problem may place you at great risk. So if you look for a solar charge controller, it’s imperative that you think about safety at all times. The average model comes with integrated protection against short-circuit, reverse polarity, overcharging and overheating. Use aspects of your trips as references and determine necessary safety features for the solar charge controller of your rig. 

Endurance 

While moving between locations, recreational vehicles and virtually everything on them experience constant vibrations which make endurance a key consideration. The last thing you want to do is to spend big bucks on flimsy controllers that fail shortly after purchase. By assessing construction material, assembly design and similar attributes, you could tell how well a model holds together in use. Besides making direct evaluations, it’s a good idea to glance through several customer reviews and see what they say about the controller you like.

Ease Of Installation 

Embracing RVing means you need to deal with countless issues so you have no time to spare on devices with complicated and lengthy setup processes. Thus, as you seek the best solar charge controller for RV, you have to give ease of installation some thoughts. In normal cases, you should be able to gauge the complexity of the setup process of a model if you read its owner’s manual. Of course, the option of hiring people to handle the installation is always available but that would incur extra expenses. 

Price

The price tag of solar charge controllers for recreational vehicles varies between dozens and hundreds of dollars  depending on types. Overall, MPPT models tend to cost more than their PWM counterparts but in exchange, they have superior energy conversion rate. Based on the way you use your solar system and the amount of power your rig consumes on the road, you could create an appropriate budget for your solar charge controller.

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Types of Solar Charge Controller

The number of solar charge controllers for recreational vehicles certainly seem overwhelming but all models could be split into three types: Shunt, PWM and MPPT 

Shunt Charge Controllers (On/Off)

With limited functions and features, shunt charge controllers tend to be considered as the most basic choices for solar systems. In use, models of the type just stop the charging current when the charge of batteries reaches a particular level. The simplicity of shunt charge controllers let them operate in variable conditions with relative ease. 

Shunt controllers function by allowing the current from the sun array to flow to the battery until a set voltage, called the disconnect voltage, is reached. When this voltage is reached, the solar array is “shorted” (or short circuited) by a transistor or relay, preventing any further current from flowing to the battery. 

Without any charge current, the battery voltage will drop until a set voltage, called the reconnect voltage, is reached. Then, current is allowed to flow to the battery again.

Shunt solar charge controllers are also called on/off regulators, as the charge regulation is either on or off. This means the solar array is either on or off, or the battery sees the full charge current as either available or none. This makes the shunt controller essentially a single-stage charger. 

A limitation of this type of solar charge controller for RV is that they are generally only used for small solar systems, like what you would equip a van. This is because the shunt charge controller gets pretty as it allows the flow of the full current from the solar array during regulation.

Series Charge Controllers 

A series charge controller functions very much like a shunt controller and is also an on/off type. Like their shunt counterparts, they also open circuits or connect the solar array using a relay or transistor as the battery reaches a set voltage. The array is reconnected when the battery voltage drops to a certain voltage, and current is allowed to flow to the battery again.

The difference is while a shunt controller has a single relay or transistor, which makes it simply a single stage charge controller, some series controllers can control multiple relays or transistors. Additional relays allow for multiple disconnect/reconnect set points and thus stepped charge current, making this type of solar charge controller a multi-stage controller.

Another advantage of this type is that as the controller connects the solar array to regulate the battery voltage, series controllers run much cooler than shunt regulators, especially if a relay is used instead of a transistor. This alone makes series charge controllers more well suited for larger solar arrays.

PWM Charge Controllers (Pulse Width Modulation)

These devices are the most commonly found solar charge controllers for RV on the market today. They were born later than the shunt versions, but are still considered older models when it comes to solar charge controllers, thus they’re often cheaper. 

They can cost anywhere from $50-$400 depending on the power rating and other features, which will be discussed further below. There are also fewer internal parts to break.

Capable of bringing batteries to max capacity and maintaining the charge level with trickle charges, PWM charge controllers excel at keeping battery banks topped-off. A PWM solar charge controller will provide enough current to the battery that it requires for its voltage size. After the right voltage has reached your battery, it’ll detach it from the panel and ensure the battery maintains the voltage point. 

For instance, when a solar panel produces 18 volts of energy, the charge controller has to convert that to a safe 13.8 volt that is healthier for the batteries to consume. Standard charge controllers will effectively “throw away” any voltage above 13.8 volt so some of the energy produced will be wasted.

So it’s easy to see that PWM charge controllers are useful at preventing overcharging. However, only supplying enough energy to hit your battery’s voltage requirement and throwing away the rest is a huge inefficiency. This is its significant disadvantage compared to the more modern and advanced MPPT charge controller. 

Overall, PWM charge controllers would make a good option when you urgently need something to get the job done at a low cost or if you don’t travel that often, so some loss of energy produced can be allowed. Such energy loss in the long term would be undesirable though.

Note: If you ever come across an inexpensive charge controller that says something like “MPPT simulating”, it’s just a PWM in disguise. An MPPT controller is electronic and more advanced, thus cannot be as cheap by any means. 

MPPT Charge Controllers (Maximum Power Point Tracking)

If you only plan on using your solar panels during a summer trip, a PWM solar charge controller would be the more economical and reasonable option. But if you camp full-time and plan on using solar energy all the time, seasoned campers would advise you to spend the extra money on the best MPPT charge controller for its tremendous benefits. 

MPPT solar charge controllers feature more advanced technology than their PWM counterparts, which is a technology borrowed from the commercial and residential solar industry. A charge controller with MPPT technology will deliver from 10% to 30% more energy from the solar panels to the RV batteries than the average PWM models. 

Technically, this is actually not because MPPT makes the controller more “efficient”, instead MPPT works smarter. A MPPT solar charge controller can adjust the input volts from the solar panels to match the output volts required for your batteries without much energy being wasted away.

An MPPT solar charge controller comes in handy during sunny days, when your solar system often generates more voltage than your RV battery requires. The MPPT unit can convert this extra voltage into more current. It will then use this extra current at a lower voltage without losing any power. 

For example, if your panels are producing 18 volts at 6 amps, the charge controller will adjust this by supplying 13.8 volts to your batteries and converting the remaining volts to amps, thus increasing the amps to, say, 7 amps. Increasing the amps this way will allow your batteries to get the most available power.

Another way to look at this is an MPPT solar charge controller allows the voltage from the array to vary from the battery voltage. By varying the array’s input voltage, the unit can find the “maximum power point” at which the solar array produces the maximum power. 

Each solar panel has a different maximum power point, that is a point at which voltage and current (amperage) peak. An MPPT controller is “smarter” as it is specifically engineered to detect this point and adjust itself to achieve maximum power output. With this smart adjustment, you can make use of your solar panel’s full power to charge your battery with no loss to the power produced. 

Since MPPT charge controllers can vary the charge current to the battery, they can be a multi-stage charger with bulk, absorption, and float settings. 

The ability to allow the voltage from the sun array to vary from the battery voltage means an MPPT unit is the ideal choice when your battery’s voltage and the solar panel’s voltage doesn’t match. In addition, the best MPPT charge controller models are also better suited for larger batteries and big, sophisticated solar systems with higher voltages, while a PWM controller will not work in these circumstances.

The only catch is these solar charge controllers are much more expensive than your standard PWM units. A good MPPT charge controller can cost $250-$700 depending on the power rating and other additional features. If you have a limited budget, you might not have to settle with buying a MPPT charge controller.

Depending on the size of your solar system, you can keep your old controller and add another panel. In some cases,  adding another solar panel to the system would cost about the same as getting a new MPPT controller and you’d also get the same benefits. 

Voltage Set Points

Typical connect & disconnect set points for 12-volt lead-acid batteries at 77° F (25° C):

• High limit (sealed battery): 14.0 volts
• High limit (flooded battery): 14.4 volts
• Resume full charge: 13.0 volts
• Low voltage disconnect: 10.8 volts
• Reconnect: 12.5 volts

Comparison: MPPT Vs. PWM Solar Charge Controllers Recap

• Charging Stage: In the course of operation, the PWM controller usually charges batteries in three stages: bulk, float and absorb. For the MPPT controller, the process consists of multiple stages. 
• Conversion Rate: The average conversion rate of the PWM controller deviates between 75% and 80% while the conversion rate of the MPPT controller may go up to 99%.  
• Expandability: PWM charge controllers could readily support solar systems with total capacities exceeding two kilowatts. In the case of MPPT controllers, they mostly see use in solar systems that have total capacities below two kilowatts. 
• Price: The price of PWM charge controllers is lower than that of MPPT charge controllers. 

In conclusion, if you have money to spend and like to reduce energy loss, you should stick to MPPT models. If you have a tight wallet and only need a robust charge controller, a PWM model would suit you well.

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Top RV Solar Charge Controller Brands

The label of a controller rarely dictates its values so you don’t have to worry too much about brand. Nevertheless, if you opt to buy your controller from a reputable brand then keep an eye out for these names 

Renogy

With a practical and user-oriented mindset, Renogy is known as one of the leading brands in the solar industry. For owners of recreational vehicles that desire a no-nonsense solar charge controller, Renogy is the number one choice. 

WindyNation

Thanks to substantial investments in technology updates and design optimization, WindyNation is capable of producing solar charge controllers with outstanding adaptability and tip-top longevity. If you buy from WindyNation, you don’t have to think about replacements for years. 

Go Power 

Being a well-established brand, Go Power understands what it takes to assemble products that meet the expectations of customers. Needless to say, Go Power is held in high esteem by a lot of RVers, novices as well as veterans. 

EPEVER

As a somewhat young company in the arena for the best solar charge controller for RV, EPEVER has made quite a name for themselves over the last decade by engineering top-notch products on top of their clear focus on their customer’s needs and satisfaction. Perhaps because the company is trying to gain credibility in a tough market, it tries extra hard to listen, respond and assist its customers. From what the reviews suggest, their customer service is also superb.

HQST 

As HQST places emphasis on applications of innovations into production techniques, its controllers boast excellent potential while remaining budget-friendly. Because of that, in terms of cost-value, products from HQST don’t have many competitors in the market nowadays. 

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How To Wire Solar Panels With A Charge Controller

There are two ways to wire solar panels together depending on the type of solar charge controller you get: series and parallel.

Parallel wiring

If you have a PWM charge controller, wire your solar panels in parallel. To do this, simply connect all the positive terminals of all the solar panels together, and all the negative terminals of all the panels together.

This will get you more amps. For example, if you had 4 solar panels in parallel and each was rated at 12 volts and 5 amps, the entire array would be 12 volts at 20 amps.

It should be noted that panels wired in parallel need combiners, fuses, and bigger wires, and all of these will cost you more money and time to install. On the up side, if one panel is shaded it will not affect the whole string. 

Another note is that you should not connect in parallel panels of different brands, even if they are of the same voltage. Connecting different solar panels in a solar array will either the voltage or the current might get reduced. This leads to lower output power.

Series wiring

If you have an MPPT controller, then wire your solar panels in series. When wiring panels in series, connect the wire from the positive terminal of one solar panel to the negative terminal of the next panel and so on. 

When stringing panels in series, each panel adds to the total voltage input of the system but the current (amperage) remains the same. The reason why series wiring are utilized with MPPT controllers is that as above, MPPT charge controllers are able to accept a higher voltage input, and still be able to charge your 12-volt or larger batteries.

This setup allows the charge controller to figure out the most efficient way to distribute power. No fuses, combiners, or oversized wires are necessary.

One limitation of this setup is when panels are wired in series, they all in a sense depend on each other. If one panel is in the shade, it will affect the whole string. This will not happen in a parallel wiring.

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Tips For Installing A DIY Solar Charge Controller

As always, carefully read the instructions for your specific solar charge controller. In general, the process should look something like below:

• Important note: First and foremost, remember that you must always connect the solar panels last. You don’t want current running into the controller with nowhere to go. 
• Where to mount the controller: To reduce current loss, install the controller as close to the batteries as possible with enough of a gap for heat ventilation. This close setup also allows certain charge controllers that have an internal temperature sensor to have an accurate estimate of battery temp for optimal charging. And don’t install a charge controller above the batteries. You don’t want any off-gassing to disturb the controller’s electronics.
• Make sure to fuse the (+) wire close to the battery so any system short circuit won’t start a fire.
• Protection against faulty controllers: Lastly, if the charge controller has an external ground (chassis ground) terminal on it, you should run a separate wire from this directly to the vehicle chassis. Your instruction manual will most likely instruct you to do this anyway. As for why you must do it, it’s very complicated. You only need to know that a vehicle is different from most other types of electrical systems. And if there is an internal fault inside the controller, electricity will still has a path back to the battery to properly pop the fuse.

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How To Test An RV Solar Charge Controller

First, preparation and safety measures:

• Solar panels produce electricity when exposed to light. Cover the front of the solar panel when handling the panel other than taking measurements.
• Prior to conducting any tests, you should verify the system wiring is correct and intact.
• Check all the connections and terminals for good electrical contact as this is the number one culprit of non-performing solar systems. 
• If all the connections appear to be in order, check the fuses in the system to ensure they are not blown. 
• If all of these preliminary checks are ok, you will simply need a multimeter capable of measuring voltage (V) and current (A) and sunlight.

Then, measure operating current as follows:

• Make sure the meter selection is set to measure DC Amps and the test leads are in the correct port to measure DC Amps. 
• Ensure that the multimeter is set at 10A to start with. You can change the setting later if required.
• Connect the panel to the charge controller and then to the battery.
• Disconnect the positive cable between the battery and the charge controller.
• Measure the operating current by connecting the +ve from the multimeter to the positive cable from the controller, and the -ve from the multimeter to the positive battery terminal. This measures the current that the panel and charge controller are supplying to the battery. If you connect  the multimeter the wrong way round then you will get a negative current reading.
• Remember, if the battery is full it may not be accepting current, resulting in a low or zero  reading.

Then, to test the solar charge controller:

• Re-connect the solar panels directly to the battery without the controller.
• Disconnect the positive cable between the battery and the panels.
• Measure the operating current by connecting the +ve from the multimeter to the positive cable from the panel, and the -ve from the meter to the positive battery terminal.
• If there was no current when the regulator was in place, but there is now current without the controller, then two possibilities are: 
  • Loose cable connection at the charge controller terminals. Disconnect and re-attach the battery and solar cables from the charge controller, making sure that there is solid electrical contact to the charge controller terminals. This is the most common problem. OR
  • There is a possibility that the charge controller could be faulty.

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FAQs About RV Solar Charge Controllers

You can also find our guides on how to choose the best RV battery, best lithium battery for RV, best AGM battery, best RV battery box, best RV surge protector, best RV generator, best solar-powered generator for RV, best solar panels for RV, best RV converter, best RV inverter, best deep cycle battery chargers, best trickle chargers, best RV battery monitors with detailed reviews in RV Electrical category. In these reviews, we only include and recommend the best products with the highest ratings among highly sold products on the market.