RV Solar charge controllers regulate voltage and help ensure that your RV’s batteries are not damaged. But there are 2 types to choose from. So, let’s compare MPPT vs. PWM charge controller for RVs.
MPPT charge controllers are better than PWM because they provide 25% more power. They are also sturdier, with built-in transformers, and can accept higher voltage input. Additionally, they are made with better quality materials and have a longer warranty.
But there’s more to know.
In this article, we’ll find out how solar power works in an RV and the advantages of using an MPPT charge controller. But we’ll also explore why MPPT is better than PWM.
Let’s get started.
How does solar power work in an RV?
An RV’s solar panels convert sunlight into electrical energy, which is then stored in the battery, and from there, powers the RV’s outlets and appliances. A charge controller helps regulate how the battery is being charged, while an inverter converts DC electricity to AC electricity.
There are circuits in the solar panel’s cells that are responsible for the conversion. Then, wires feed the electricity to a charger controller.
To understand the above better, here are the key components that make up the solar power system in an RV. I figured it’d be easier to have a better appreciation when we know what each part does.
- Solar Panels
- Charge controllers
- Power Inverters
- Power converters
I’ll explain the first two since they are the most important and unique to solar power.
A solar panel is filled with cells that capture energy from the sun and convert it into electricity that is usable in your RV. There are mainly two types of solar panels: monocrystalline and polycrystalline.
The former is more efficient and a tad more expensive. If you have a small RV with little space in the roof, monocrystalline panels may be too small. But polycrystalline panels work fine if you have the space.
Solar panels come in flat or flexible forms. Flat solar panels are more affordable, more durable, and come with a better warranty. Flexible ones, on the other hand, are lighter, more dynamic, easier to mount, and in some cases, more aesthetic.
Now let’s find out a bit more about charge controllers
An RV battery can handle 12 volts, while solar panels typically provide between 16 to 12 volts of electric potential. A solar charge controller is a standard part of a solar installation that prevents battery damage by regulating current and voltage.
The standard is adequate for most RVs. But if you have an unusual setup or live in a very cold region, you may want to talk to a pro to help you get one that’s ideal for your situation.
RV Solar charge controller & inverter build progress today 🙂 pic.twitter.com/g1q4zshadB
— Gavin Remme (@gevan32) April 16, 2021
What are the advantages of using an MPPT solar charge controller in my RV?
The advantage of using an MPPT solar charge controller in an RV is that it can generate up to 25% more power. But it also has more features, more room for expansion, and can also be used for higher voltage.
MPPT solar charge controllers convert the high voltage from solar panels to the low voltage needed to charge batteries. The most important advantage is that they help you access more power in your battery.
They work in such a way that they can draw the maximum power from the solar panels.
They are regularly making adjustments so as to align the output from the panels to the input that’s going into the battery. As they do this, they’re monitoring light and temperature conditions. They work very well even when the weather is cold or when the battery has been seriously depleted.
Most MPPTs are 93%-97% efficient with the conversion process such that, on average, you get a 20-45% gain in winter and 10-15% gain in summer. They’re usually manufactured with higher quality material, and their warranty can be up to five years.
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I compared charge current between a PWM and a MPPT solar charge controllers. I have 20W/18V solar panel and 12V/2.2Ah battery. Under low light condition the $13 PWM charge controller (LS0512EU left) gave 36 mA while the $8 MPPT (CN3722 module right) gave only 22mA. pic.twitter.com/svrxIWUr4O
— Jasper Sikken (@jrsikken) May 26, 2018
Why is MPPT better than PWM?
MPPT is better than PWM because it is more advanced, the conversion rate is higher, it’s more flexible for system growth, and it allows for a panel array to be of higher voltage than the battery bank.
MPPT (Maximum Power Point Tracker) enables the solar panel to operate at the maximum voltage for maximum power output. On average, MPPT can be 30% more efficient than PWM (Pulse Width Modulation).
When PWM is used, the solar panel’s voltage must drop to match the battery’s voltage. Naturally, the output is reduced greatly. But with MPPT, the solar panel can operate at its maximum power point, consequently generating more energy.
MPPTs also have in-built transformers and are made with better quality material. Naturally, they are often more expensive than PWMs.
Our RV Solar Kit comes with the CNBOU 40A MPPT Charge Controller. LARGE HEAT SINK = BETTER COOLING pic.twitter.com/21n9U7lc6j
— CNBOU America (@cnbouamerica) November 9, 2017
Which type of charge controller is the most efficient for an RV?
MPPT is the most efficient charge controller for an RV because it allows for up to 25% more power, allows for higher voltage from the panels, and provides room for expansion as the power needs increase.
That said, if you’re not going to ever use more than 300 watts, you can make do with a PWM. But if your requirement is more than this, or you envisage that it would be, MPPT is the way to go.
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But what if what’s right for your set-up and budget is a PWM? That’s the next stuff we’ll check out.
I’ve a cheap non-brand PWM solar charge controller of dubious specifications to play with 😉 pic.twitter.com/zj15JpzE2g
— Matt (@matt303) July 1, 2019
What is the best PWM solar charge controller?
The best PWM solar charge controller is Morningstar – SunSaver 10A PWM Solar Charge Controller for 12V Batteries. It has built-in diagnostics and has the lowest failure rate in the industry.
CLICK HERE to see it on Amazon.
It’s designed to be used in small systems with max/load current up to 20A. It is tropicalized and is ideal for field use, and is also great for networked systems through communication protocols.
It’s got advanced self-diagnostics that warn against user error and built-in protection against surge, short-circuit, over-current, and reverse polarity conditions.
It has the lowest hardware failure rate in the industry and is backed by a five-year warranty. Its highly durable polycarbonate exterior case is a reflection of industrial-strength build quality.
Advanced thermal engineering was employed in the design, and most of the products by Morning Star are so durable that some are still in use a quarter of a century after they were manufactured.
It’s got over 100 reviews on Amazon, and most of them are 5 stars. Click here to check it out.
What is the best MPPT solar charge controller?
The best MPPT solar charge controller is the Outback Flexmax 80 Solar Charge Controller which ranges from 12V to 60V. It is an 80 AMP controller and can yield up to 30% more power than other types of controllers.
CLICK HERE to see it on Amazon.
It’s designed to be used in medium to large systems with max/load current of up to 80 amps.
It comes with a 5-year warranty, and while it’s more expensive than many other controllers, it’s still well under $500 and can put out significantly more power than other controllers.
If your panels produce more electricity than the controller can handle, the auto-protect mode kicks in and the controller automatically shuts down, preventing damage.
And while it can produce up to 80 amps, it will automatically self-adjust based on the number of batteries you have connected.
It’s got over 500 reviews on Amazon, and most of them are 5 stars. Click here to check it out.
In this article, we found out how solar power works in an RV and the advantages of using an MPPT charge controller.
But we also explored why MPPT is better than PWM.
Then, we looked at which type of charge controller is the most efficient for an RV. Lastly, we wrapped things up by considering the best PWM solar charge controller.
Photo which requires attribution:
Flexible Solar Panels Mounted by RVWithTito.com is licensed under CC2.0 and was cropped, edited, and had a text overlay added.