In this article we are going to discuss the use of an RV solar system.
How do they work anyway? How much will it cost you? Can you install it yourself? What are the pros and cons of using solar power?
Also, when is solar power needed? And should all RVers have a solar system installed in their RV?
Let’s get started and try to answer those questions now!
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Table of Contents
- How Does An RV Solar System Work?
- What Are The System Components You Will Need?
- How Many Solar Panels Will You Need?
- Solar Charge Controllers
- Your RV Solar System Battery Bank
- How Many Batteries Will You Need?
- What Is The Inverter Used For?
- What Kind Of Inverter Is Needed?
- Wiring For An RV Solar System
- The Pros Of RV Solar Systems
- The Cons Of An RV Solar Power System.
- Who Needs A Solar Power System?
- Conclusion
How Does An RV Solar System Work?
Put simply, an RV solar system gathers sunlight and converts it into energy that is then stored in your battery bank.
It is important to understand that solar panels usually do not run any appliance or item on their own. Instead, they create DC electricity that can be used to power whatever appliance or item is needed.
So a group of solar panels needs a bank of batteries to store the electricity that they create.
Also, there is another piece of equipment needed between the solar panels and your batteries. It’s called a solar charge controller.
This is necessary to avoid overcharging your batteries and damaging them.
When the battery is at full capacity the solar charge controller limits the incoming electricity from the solar panels. It then maintains just enough charge to keep the batteries in their fully charged state.
What Are The System Components You Will Need?
There are 5 components of a proper RV solar system that you will probably need, and they are:
- Solar panels
- Solar Charge Controller
- A battery bank
- An inverter
- Heavy gauge wiring and fuses
As you can see, there are several components of a solar system. And added together, the cost is not cheap either.
Also, the real work involved is in actually installing the system into your RV. And unless you are very familiar with solar power systems, you really should have a professional do it for you.
If this equipment is installed incorrectly, there could be serious safety hazards at play. But on the other hand, having that professional installation really increases the cost of the system.
So a small solar system for an RV can only be a couple thousand dollars in cost. But if you go for a high end system you may be looking at $10,000 – $15,000 or more, including installation.
Most RV solar systems you see in use today will fall somewhere in the middle for cost. That is, about $4000 – $6000 including installation.
Let’s discuss each one of the solar system components now, starting with the solar panels.
Click here for a 200 watt small solar system
This link is for a 400 watt medium size solar system
Click here for a 600 watt larger solar system
(These are affiliate links for the product on Amazon. It does not cost you any extra to buy the product using my affiliate link if you choose to do so)
How Many Solar Panels Will You Need?
This is the question that most people want to know right away. And no wonder, because the roof space on an RV can limit the number of panels you can install.
Most solar panels you will see for sale come in 100 watt units per panel. So how many of those panels will be needed to accomplish your power needs?
Well generally speaking, 100 – 200 watts of solar panels are enough to recharge your batteries after a night’s usage. Especially if you only use enough 12-volt battery power to charge up your devices, and run some lights.
But if you want to watch several hours of TV, use your microwave and other high wattage appliances, you need more. Many RVers that have 400 – 600 watts of solar panels can run almost anything other than their AC units.
Solar Charge Controllers
As mentioned before, you will need to have a solar charge controller between the solar panels and your batteries. This will make sure that the batteries are protected and kept at a high level of charge.
There are two kinds of solar charge controllers in use today, PWM and MPPT. Essentially the PWM unit is a switch between the solar panels and batteries.
The MPPT unit is more sophisticated and is able to maximize the transfer of power from the panels to the batteries.
To put it in lay terms, the PWM does the job. But the MPPT does the job better and will give you as much power as you can get from your solar panels.
Of course, the PWM controller is cheaper than the MPPT controller. Either one will do the job fine. But the MPPT will probably pay for itself over time with the extra power it produces.
Your RV Solar System Battery Bank
The subject of batteries and which ones to use for an RV solar system is complicated and lengthy. So for this article let’s focus on how many watt hours will need to be stored in the battery bank.
Generally speaking you will need about 100 amp hours of “usable power” to run most small 12 volt items in the RV daily. This includes lights, fans, charging small devices and maybe even a couple hours of 12-volt TV.
But you need more power if you want to run 120 volt appliances like a microwave, hair dryer, coffee maker, etc. Probably about 200 – 250 usable amp hours of power will be needed in that case.
What is meant by the term “usable power”? Well, if your battery bank is made up of lead acid batteries, you can only use 50% of their amp hour limit.
This is because if you drain those batteries any lower than that consistently, you will damage the batteries. So if the battery capacity is 100 amp hours, but you only use 50%, you only have 50 usable amp hours of power.
How Many Batteries Will You Need?
Many RVers use 2 6-volt golf cart batteries wired together in series to make the 12 volts needed for an RV system. These kind of batteries are popular because they last a long time and can take a lot of repetitive charging and discharging cycles.
A golf cart battery is often rated for 200+ amp hours and these remain constant for both batteries used together this way. This is because when batteries are wired in series, the voltage is doubled, but the amp hours remain the same.
In this arrangement, the “usable amp hours” is about 100, not the full amp hour limit of the batteries. Remember, this 50% discharge rate is to make sure that your batteries last a long time without damage.
Some RVers have an RV solar system that only has to produce about 100 amp hours per day for their power needs. And in that case, the 2 golf cart batteries wired in series will work fine.
But if you want to run more power intensive items in the RV, you will probably need at least 4 of those batteries. This will allow you to store around 200 amp hours of power daily.
Of course, you have to have more solar panels to adequately fill a larger battery bank too. So more amp hours requires more batteries, which also requires more solar panels to fill them.
Much more can be said on this subject, but that is for another article.
Click here for a 4 battery bank set usable for solar power
(These are affiliate links for the product on Amazon. It does not cost you any extra to buy the product using my affiliate link if you choose to do so)
What Is The Inverter Used For?
This is a part of the solar system that most people aren’t too clear about. So what does an inverter do anyway?
To answer that, let’s see what our solar system is capable of doing so far. We have a group of solar panels feeding electricity into a bank of batteries that produces 12 volt electricity.
These 12 volts can be used for any item or appliance that runs on 12 volts. But what about all of the appliances and devices that need to run on 120 volts instead?
They are easily recognizable by the power cord plug that goes into a residential home type of wall socket. So, can you even run those appliances and devices from batteries?
The answer is yes. But only if you use an inverter. It effectively steps up the voltage coming from the batteries from 12 volts to 120 volts as needed
What Kind Of Inverter Is Needed?
So if you plug in a blender to the wall socket in your RV, it can run just fine. But only if you have the right size inverter to manage the electrical load needed.
Inverters come in two main varieties, True Sine Wave and Modified Sine Wave. And they can come in several sizes.
The details of which inverter best meets your needs is just too lengthy a discussion for this article. So here is a little information that can help you learn more about real world usage of inverters in an RV.
Suffice it to say that if you want to run 120 volt devices in your RV, you will need the right size and kind of inverter to do the job.
Click here for a Xantrex 2000 watt inverter
Click here for a Xantrex 3000 watt inverter
(These are affiliate links for the product on Amazon. It does not cost you any extra to buy the product using my affiliate link if you choose to do so)
Wiring For An RV Solar System
The final ingredient in an RV solar system is heavy gauge wiring and fuses.
This is where a lot of mistakes are made by DIYers. They get all the correct pieces of equipment, but join them together with insufficient wiring.
This is a safety issue. So make sure that the wiring is appropriate for whatever size solar system you choose for your RV.
To help with those calculations, here is some information about proper wire sizing and fuses for use in RV solar systems.
The Pros Of RV Solar Systems
So here are the pros of installing an RV solar system in your RV:
- Quiet – solar systems make no noise at all. Even inverter generators make some noise.
- A solar system allows you to take your RV off-road and still have modern conveniences with you. This is because you can produce the power for those devices without being hooked up to a power grid. You are your own power grid!
- There is very little to go wrong with a solar system. And almost no maintenance either.
- Solar power is good for the environment. It is clean energy that produces no waste or pollution.
The Cons Of An RV Solar Power System.
Of course, as with anything, there are cons to be considered too. And here they are:
- The cost – An RV solar system is not cheap, especially one big enough to handle most of your daily power needs. The main ingredient that increases the cost is professional installation. But unless you really know what you are doing, it is really necessary in most cases.
- Solar power loses effectiveness on cloudy days. In some cases the power output from your solar panels may drop by 75% on cloudy and rainy days.
- Solar can’t be expected to run air conditioning units on RVs in most cases. Of course, very high end large solar systems can run ACs for a while. But not continuously for more than just a few hours at a time.
- If your solar power system is permanently mounted on your RV, it will go with the RV when you sell it. It just doesn’t make sense to install a large solar power system on your RV if you plan to sell it soon. It will not be cost effective to do so. The cost of solar power can only be recovered over a long period of time.
Who Needs A Solar Power System?
Solar power only becomes really useful if you plan to camp off-grid a lot.
Camping while unplugged from shore power is often called boondocking. And if this is the style of camping that you prefer, solar power makes a lot of sense for you.
You can literally take your RV almost anywhere and produce power while the sun shines. There is a lot of freedom in that kind of capability!
On the other hand, if you like to spend most of your time in campgrounds, solar power may not be the best choice.
Campground camping usually means being plugged in to a source of AC power. And that kind of power can run everything in your RV, including air conditioning units, quietly.
So why go to the expense of adding solar power unless you really plan on using it?
Conclusion
An RV solar system really shines when it is used for boondocking and off-grid camping. And it even becomes cost effective if you keep your solar-powered RV for a long time.
But clearly, it is very expensive. And it’s not very cost effective if you mostly stay in campgrounds and trade RVs regularly.
So decide whether solar power is something you really need. It’s simply not for everyone!
Have safe and happy travels my friends!