Of pivotal importance to a solar energy system installed in an RV is the solar charge controller. This important device ensures that the solar panels installed on the roof of your RV are charging your battery to the best of their ability, so, you could say, it is a key component of the whole solar system. With so many solar charge controllers on the market, we take a look at some of the best ones out there and go through what you need to consider before choosing the correct model for you.
Best PWM Solar Charge Controller
Renogy Wanderer – 30A Advanced PWM Negative-Ground Solar Charge Controller Review
If you are after a solar charge controller that won’t break the bank but has excellent capacity, safety and efficiency features, then this beautifully designed and easy-to-use device from Renogy will suit you just right. The intuitive LED system helps you understand when a battery is charged or charging and what battery type you have the controller set up for.
With a powerful 30A rating you have up to 400 watts of solar power handling capability, equivalent to 4 x 100-watt panels at a peak rate of 7 amps. This charge controller also works great with AGM batteries as it is able to support higher voltages than comparably priced controllers. It also has an extra charging phase, helping to both protect against battery damage and increase charging speed by ensuring consistent voltage for the final 20% of the battery charging cycle.
The safety features of this charge controller will fill you with confidence that your solar power system is protected from the vagaries of the weather, as it will regulate temperature to ensure appropriate charge is given in the hot or the cold. This great value product, with plenty of special features, is hands down the best PWM solar charger out there.
Q&A: Can you adjust the float voltage with this unit?
A: This is not possible for this device.
Q&A: Can this unit be mounted against a flat surface without cutting a venting hole at the back?
A: The Renogy can be mounted like this, just make sure the front side is open so the fins can dissipate the heat as it builds up.
Best MPPT solar charge controller
EPEVER Upgraded 30A MPPT Solar Charge Controller Review
This super-efficient MPPT solar charge controller from Epever helps you to get the maximum power out of your solar panels to feed your battery needs, with at least 99.5% power-tracking efficiency. This helps it to properly distribute the volts/amps adjusted appropriately and speed up charging times, whilst achieving this with the minimum of fuss thanks to automatic system voltage recognition.
This charge controller, complete with a remote monitor, works particularly well with Gel and flooded lithium batteries and the inbuilt LCD display shows you all you need, from how much your solar panels are producing to battery status, allowing you to have extra control over your system. Rated at 30A you can also use this unit for up to 4 100W solar panels, making this a great choice for keeping your RV energy needs powered-up.
The one down-side of this product is the design, so you might want to find a slot in a cupboard for it. However, other than this, it is great value for an MPPT charge controller, efficient and extremely user-friendly, so well worth seeing the beauty on the inside.
Q&A: Does this come with mounts?
A: Only the remote monitor has mounts included, but you only need a few screws to mount charge controller itself.
Q&A: Does this come with monitoring software?
A: Not exactly, but there is an inbuilt MT-50 monitoring component as well as free to download software from the manufacturer. If you wish to download the data on to your computer you will need an appropriate USB cable.
Best Solar Charge Controller for RV
Outback Flexmax 80 FM80 MPPT 80 AMP Solar Charge Controller Review
If money is no object and you are looking to maximise the green energy you’re able to utilise for a variety of voltage requirements, then this product from Outback is the cream of the crop when it comes to RV solar charge controllers. This MPPT controller, is in fact, capable of charging batteries from 12V through to a whopping 60V, so if your RV has a variety of devices, you love being off-grid, and you want to protect your batteries, this unit offers you everything you need.
The built-in backlit display highlights all the performance data you will need and you are also able to access your data history for the last 4 months at the touch of a button, so if you really want to get nerdy about your solar power system this offers you all the data you could dream of. The regulation of charge rate based on calculations regarding the battery condition is all automatic too, so you can relax as you tuck into your feast of solar data.
Thanks to the intelligence and high-efficiency continuous tracking of this unit, the amp hours you are able to draw from your rooftop solar panels and direct safely into your batteries will increase dramatically. This protects your battery lifespans whilst giving you all the necessary juice for any off-grid party.
Q&A: Can more than one of these be used to charge the same battery bank?
A: You can, this works best with additional equipment which allows you to set and optimize parameters on each of the connected devices (such as the Outback HUB4 or HUB10).
Best Solar Charge Controller for Lithium Battery
PowMr 60amp 48V 36V 24V 12V Auto MPPT Solar Charge Controller Review
If you’ve invested in high-end lithium batteries, then you will want to treat them with love and attention, and that is what you will get from this great unit from PowMr. It is also compatible with Vented, Gel, Sealed and NiCd battery types if you have a mixture of battery types covering your energy needs when you are enjoying the solar fuelled off-grid lifestyle.
The inbuilt automatic battery voltage detection temperature compensation and three stage constant current charging helps to ensure longevity in your battery life-cycle, whilst the two connectors for each positive and negative on your solar battery connectors are also a useful feature. It is also simple to use straight out of the box, so no need to go searching through the slightly difficult to interpret user manual.
The useful inbuilt LCD screen provides all the information you will need to track your solar system’s energy efficiency, including both the voltage and amps. So if you want to keep your top of the range batteries in good health with ease, this great solar charge controller will be just what you are looking for.
Q&A: Can 2 of these be connected to make 80-amps?
A: They can, just make sure both solar panels and the batteries they are connected to are the same.
Q&A: What is the max current for each battery voltage 12/24/48?
A: The data sheet indicates the max current for a battery is 60-amps, and that there is a current limit protection circuit which trips at 61-amps.
Best Solar Trickle Charger for RV Battery
Sunway Solar Car Battery Charger 12V Battery Trickle Charger Review
If you’ve already selected your charge controller to protect your solar energy system, then you should also be thinking about protecting your battery life when they need charging. A key instrument to achieve this end is a trickle charger, and this solar trickle charger that also acts as a maintainer would be a great addition to your setup to help prevent sulfation from battery drain.
The beauty of this trickle charger is that it is able to keep your battery topped up with the warm rays of the sun thanks to its high-efficiency crystalline panel. It is also easy to both connect and disconnect this with your battery, has built in diodes to prevent reverse charging, and comes complete with cigarette light plug and battery clamps. Just make sure you remember to clean the solar charger at least monthly to maintain optimal efficiency.
This excellent trickle-charger, for a very reasonable price, will help to ensure your less-used batteries are maintained in fine health with ease, giving you the peace of mind you need for those periods when you put your RV into hibernation from regular usage.
Q&A: Is this suitable for outdoor use?
A: This is weatherproof so no problem to use outside. Also, although it is not waterproof and should not be fully submerged under-water, it does survive well in difficult conditions if you do accidentally leave it attached on occasion.
Q&A: How long is the cable on this charger?
A: The cable is about 6 feet long.
Best Solar Battery Tender for RV
Battery Tender 021-1163 5W Solar Maintainer Review
If you are just after installing something and leaving it attached indefinitely to keep your batteries topped up and in good health, then you should consider opting for a battery tender for your solar system. This little number from Battery Tender works a treat responding as soon as your battery voltage drops below a certain level and kicking in with some juice. This also comes in 5 to 15-watt variations, if you have higher output requirements in your setup.
You can feel safe to leave this connected thanks to the temperature compensation sensor, so whatever the weather your batteries will be charged appropriately, helping to improve their life-cycle. It also has spark-proof protection, built-in overcharge protection, and is waterproof, meaning once its setup you can leave it to its task worry free.
The efficient solar panel easily performs up to the stated 10W in ideal conditions, although you will not achieve such great results in cloudy or shady spots. Nevertheless, so long as you keep this panel regularly cleaned you will be very pleased with the results you get, just from harnessing the free solar resource available to us all for free. This tender power supplier works so well you’ll likely soon be installing more than one.
Q&A: How long are the cables that come with this product?
A: The lead wired into the panel is 60 inches long and the alligator clip lead is 24 inches.
Q&A: Does this come with mounting brackets?
A: No, but it has 4 mounting holes in each corner so it is easy to install.
Best Solar Battery Maintainer for RV
Schumacher SP-400 4.8W Solar Battery Charger / Maintainer Review
If you are after the market leader in battery-life extension, then this solar powered battery maintainer form Schumacher is a great option. The super efficient panel also works wonders even in cloudy weather, so you don’t have to be constantly worried about chasing down sunny spots if you don’t want to.
This device comes complete with everything you’ll need to get started, including: the solar panel itself, a 12V DC adaptor cable, as well as a clamp adaptor and mounting screws. The user manual is also well laid out and easy to follow, so you’ll have this little beauty set up in no time. It’s also very lightweight and portable if you don’t just want it installed in one spot and plan to take it out on a variety of adventures.
You will find this device so reliable at keeping under-used batteries topped up and maintained, that you will no doubt find yourself investing in a few of these before long, and that would be a great idea if you want to build a long-lasting solar power supply for your RV. You will definitely want to pair it with a solar charge controller though, if you want to get the best use from it.
Q&A: Does this work with Gel Cell batteries?
A: This works well with Gel Cell.
Q&A: How long are the included cables?
A: They are about 8 feet to the two-pin quick connector.
What does a solar charge controller do?
We all know that weather forecasts are unreliable, and the weather is changeable and often unpredictable. While solar energy is an excellent renewable energy source, the energy that the sun provides varies and depends on the time of day, the season and the location your RV is in.
Due to the inconsistency of the sun’s rays, there will be periods when the solar panels are unable to absorb enough solar energy to charge your RV’s battery. At other times when the sun is bright, high in the sky and unobscured by clouds there will be a surge of energy absorbed by the solar panels and their performance will be at it’s optimum.
These two extremes in the power supply are incompatible with your RV’s battery as both extremes of energy supply could damage the battery. An absolute lack of solar energy could lead to a dangerously low discharge, reducing your battery life-cycle, whilst a surge of energy may lead to the battery overheating, again reducing its lifetime.
This is where the solar charge controller comes in. This clever device sits between the solar panels and the battery and controls the amount of energy that your battery receives, ensuring that it will not overheat or discharge to a rate that damages the battery. It is, therefore, an essential device to ensure the smooth running and longevity of the solar energy system in your RV.
What is the difference between PWM and MPTT solar charge controllers?
When perusing the available solar charge controllers on the market you will notice the acronyms ‘PWM’ and ‘MPTT’ popping up. These stand for Pulse Width Modulation (PWM) and Maximum Power Point Tracking (MPPT). Here are the key things you need to know about these two types of solar charge controllers:
Pulse Width Modulation (PWM)
PWM solar charge controllers have been around a long time and have the advantage of being at the cheaper end of the market. The technology is simple; the PWM charge controller controls the voltage and current that flows to your battery from the solar panel and allows enough current to flow to the battery to meet its voltage size. Once the optimum voltage is reached it then disconnects the battery from the panel and maintains the battery at its peak voltage.
While this type of solar charge controller is a trusted method of ensuring your battery does not overcharge, its disadvantage lies in the restriction of only providing enough energy to meet the battery’s voltage. This means that any energy generated after it reaches capacity is lost.
Maximum Power Point Tracking (MPPT)
This newer technology goes beyond the capabilities of the original PWM solar charge controllers and is a much more advanced and complex model. As solar panels are often able to generate more voltage when the sunny conditions are at their peak than your RV battery is able to handle, the MPPT solar charge controllers are able to convert this excess voltage into extra current. It then uses this at a lower voltage without losing power – this means you can use the full power of the solar panels on your RV to efficiently charge your battery.
In addition to being more efficient then PWM solar charge controllers, the MPPT is also best suited to solar panels and batteries with higher voltages. It is also the correct choice of solar charge controller when there is a difference between the solar panel voltage and the voltage of your battery, as you cannot use a PWM in this instance.
The disadvantage of MPPT solar charge controllers is that they are significantly more expensive than the PWM models. If you are going to be frequently relying on solar energy it is a worthwhile investment to splash the cash on an MPPT solar charge controller as they are able to optimise the energy collected by your solar panel most efficiently. Whereas if your solar energy needs are restricted to a summer holiday trip or a weekend away every couple of months then the PWM solar charge controllers will be a fine choice.
Why use a trickle charger or battery tender?
If you are likely to be putting your vehicle into storage for an extended period you should always make sure the battery is charged to its fullest at the time you put it into storage. However, all batteries discharge over time without charge, and so would need regular recharging over their time in storage. Trickle chargers and tenders remove the need for this.
A trickle charger usually feeds a low voltage to a battery constantly over time at a rate that is equal to the battery’s own rate of discharge. Typically you should remove a trickle charger once full charge has been reached, although some now act more like battery tenders or battery maintainers which allows you to set a rate at which you wish the trickle charge to kick in and when you would like it to turn off.
As you can see, if you wish to easily maintain your battery, whilst also preventing deep discharge when you are not using your RV over extended time periods, it is essential to have at least a trickle charger and preferably a battery maintainer.
Investing in a quality solar charge controller is a decision you won’t regret. In some ways, it can be described as the lungs of the solar energy system within your RV as it controls the amount of energy your battery receives and protects your battery from discharging too low and from overheating.
Before purchasing your solar charge controller, make sure you think about whether your RV solar needs are more suited to a PWM or an MPPT controller. MPPT are at the more expensive end of the market and would be a good choice if you are relying on the solar energy in your RV regularly. PWM solar charge controllers are a cheaper option and still do the job well and are a good choice if your solar energy requirements are on a smaller scale.