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what size solar panel for rv

How Much Solar Power Do I Need For An RV?

Are you trying to find out how much solar power you need for an RV?

Well, you've come to the right place.

If you plan to live full-time in an RV or go for an off-grid trip, installing solar panels on the RV would be a smart investment. These are low-maintenance and operate without noise or smell. 

But how much solar power and what size solar panel for RV is required? This guide will help you figure out the number of solar panels you need. 

Let’s get started!


What's In This Guide

In this guide, we introduce a proven step-by-step method to estimate the solar power needed for an RV.

We start by making sure this guide will actually solve your specific problem.

Then, we provide you with a step-by-step guide and a list of the supplies, tools, and materials you'll need to accomplish it.

Finally, we answer the most commonly-asked questions about what size solar panel for RV is needed for traveling - including the gotchas that trip up most people.

Hopefully, this guide will answer all of your questions.

But in case it does not, please leave us a comment below.


How Does a Solar System Work In An RV?

Before getting into what size solar panel for RV is required, you must understand how the solar system in your RV works. 

The solar panels are composed of individual solar cells that harvest the light energy and convert it into electricity. The energy is stored in the battery to ensure a constant power supply when the Sun is down at night. 

There is a difference between the home solar system and the one used in the RVs. In the RV, you need energy for day-to-day use, and once the battery is fully charged, the excess energy will be wasted. It is, therefore, essential to calculate the solar needs of the RV as a more extensive system will end up with a lot of wasted energy.


Calculating Average RV Consumption

The energy usage in an RV may vary for people as every person uses their RVs differently. On average, the majority of people use a 200ah battery with 800 watts of solar panels in their vehicles. 

In the table below, you can see the average electrical consumption by appliances in an RV.

RV appliances

Watts

Roof-Top AC (15,000 BTU)

2000W

Roof-Top AC (13,500 BTU)

1500W

Roof-Top AC (11,000 BTU)

1010W

Dorm size refrigerator

350W

Vacuum

1100W

Dehumidifier

785W

Clothes washer

1150W

Electrical water heater

1440W

Coffee maker

800W

Fan

200W

Electric grill

1650W

Toaster

850-1250W

1800W

27” color TV

500W

12” B&W TV

30W

Satellite dish & receiver

30W

Battery charger (cell phone)

25W

Inflator pump

50W

Laptop

200W

Next, we have a table of the average amperage drawn by the most common appliances on the RV. 

This will help you calculate what size solar panel for RV is required.

Appliance

Amperage Draw

The maximum time a 200ah battery would last (hours).

HD Television

1.5-4 Amps

40

Coffee maker

5-8 Amps

22

Toaster

8-10 Amps

20

Water heater

8-13 Amps

14

Space heater

7-13 Amps

15

Refrigerator

5-8 Amps

22

Hairdryer

7-13 Amps

15

Satellite receiver

0.5-0.8 Amps

170

RV converter

1-8 Amps

25

Furnace fan

7-9 Amps

16

Washer/Dryer

14-16 Amps

12

Microwave Oven

7-13 Amps

15

Vacuum

2-6 Amps

40

Frying pan

7-12 Amps

13

How Many Solar Panels Do I Need For My RV?

what size solar panel for rv

Sizing the solar installation on an RV requires you to consider a number of factors. A wrong calculation could lead to both time and money waste. Mentioned below is a list of a couple of things that you must pay attention to.

Peak Sun Hours

One of the most critical factors that determine the number of solar panels you need to incorporate into your RV solar system is the peak sun hours of the area. The Global Horizontal Irradiation value or sun peak hours vary for different locations.

Each country has different peak sun hours, so if you are traveling, it is important to know the accurate value for each area. With this information, it can be difficult for you to figure out the number of solar panels you need.

Electrical Consumption

The second aspect to consider while sizing a solar system for an RV is determining how much energy it consumes.

Having this information makes it easier to calculate the number of solar panels needed to power the appliances in the RV. 

A typical RV uses around 4-15kWh per day on average. 

Here is an average estimate of the total power requirement of an RV.

Appliance

Watt

Usage per day (Hours)

Daily consumption (Wh)

Small refrigerator

40

24

960

Coffee maker

1000

0.15

150

Water purifier

60

1

60

Microwave

800

0.5

400

LED bulbs (8)

80

5

400

Cellphones (3)

54

2

108

Blender

500

0.1

50

Water heater

1440

0.5

720

Plasma TV

200

5

800

Total Daily Consumption (Wh)

4848

Solar Panel Output Rating

what size solar panel for rv

Lastly, you must know the output rating of the solar panels you intend to install. Most RVs use 100 watts to 200 watts solar panels on the RV. After calculating the total energy consumption per day, you can figure out the number of solar panels required accordingly.  

You should know the difference between Watts, Amps, and Amp-Hours.

Solar panels are rated in Watts, while the batteries are rated in Amp Hours. The power can be calculated from a simple equation.

Watts = Amps * Volts, where volt is the unit of the potential.

The battery capacity in a solar system is measured in amp-hours. This means if a current of 1 amp is flowing for an hour, it will produce 1 amp-hour of the charge. A 100 watts solar panel can produce up to 8.33 amp-hours charge in an hour at peak efficiency. 


RV Solar Power System Components

what size solar panel for rv

Though some of you might think it is additional information, this is also important for proper installation. It will help determine what size solar panel for RV is needed while helping you save a couple of bucks.

Solar Panels

Solar panels are being manufactured using different technologies to improve overall efficiency. The most common types of solar panels are monocrystalline and polycrystalline solar panels.  

Does it matter which type of solar panel you get? Well, of course, it does. Monocrystalline solar panels are about 15% to 20% energy efficient, while polycrystalline solar panels are only 13 % to 16% energy efficient. 

They also differ in appearance as the monocrystalline solar panels are made from pure silicone and feature a typical square shape. They are physically smaller and more energy-efficient. However, keep in mind that they tend to fall on the higher end of the cost spectrum than polycrystalline solar panels.

Monocrystalline solar panels are reported to work better even in low light conditions and high-temperature conditions. Unless you need smaller solar panels for your RV roof, it is suggested to go for cheaper polycrystalline solar panels and save yourself some bucks. 

Batteries

The battery is the heart of the RV solar system. It's where the energy is stored to be used later so you can make it through the night. 

There are two major types of RV batteries that you'll find on the market, lead-acid batteries and lithium-ion batteries. The first of these, lead-acid batteries, have been around forever.

The lithium-ion batteries have a different charging profile from lead-acid batteries. These are more expensive and safer than the rest.

Most RVs, however, have some type of lead-acid battery to store the charge. One pro tip to extend the life of your battery is to observe the 50% rule. According to this rule, you must not allow these batteries to discharge below 50%. This will save you from replacing them sooner. 

Flexible Vs. Flat Panels

Flexible panels are more popular these days because they are lighter and easier to mount. The aerodynamic design is easier to install as you do not have to drill holes plus the best thing is that they conform to the curves. However, all these features come at a high price.

Traditional flat panels, on the contrary, are mounted off the RV surface, slowing the airflow. These are more durable with more extended warranties, plus they are cheaper as well. 

So unless there is no need to sign up for the aesthetics of the flexible panels, you should go for traditional flat panels. They are long-lasting and a budget-friendly way to get the job done. 

The Solar Charge Controller

The charge controller, as the name suggests, is responsible for regulating the charge flowing from solar panels to the battery. The power from the solar panels comes at varying voltages, and the charge controller regulates it to 12-15 volts, allowing a proper battery recharge. 

The batteries in the RV solar system are generally 12V, and a charge controller prevents them from overcharging. There are mainly two types of charge controllers out there. 

PWM stands for Pulse Width Modulation. This is an older technology, and PWM charge controllers are compatible with a certain type of solar panels. They are less expensive but also not much efficient.

The other type of charge controller, MPPT, stands for Maximum Power Point Tracking. These charge controllers are 94-98% efficient, and they are known to work exceptionally well on cold days. However, the added flexibility and high-end performance cost a lot of money. 


Choosing a Solar Panel Size

what size solar panel for rv

There are a number of methods to figure out the solar panel size. However, here is a simple one that can help you easily figure out what size solar panel for RV is needed.

Suppose your RV’s power consumption is 100ah and the average peak sun hours are six hours. According to the calculation, the solar power must store 100ah in these six hours or 16.6ah per hour.

Amperage-hour requirements / 6 = the amperage that the solar panels need to output an hour

A 100-watt solar panel gives 5.3ah power on average. In order to cover that 100ah power consumption requirement, you will need a 300-watt solar panel. However, getting a 400-watt solar panel is better to cover some extra power.

Once you have figured out the number of amps the solar panel requires to run the appliances per hour, it becomes simpler to size the solar system for the RV.

Make sure to purchase the highest quality solar panels you can afford, as they are efficient and likely to last long. 

Solar Panel Formula for RV

To help you determine what size solar panel for RV is needed, we have figured out a formula. This simple equation can help you calculate your solar demands and create the right solar system accordingly. 

(Monthly Electric Usage/ Monthly Peak Sun Hours*1000)/Power Rating of Solar Panel

Let’s take an example. 

You are planning to take a trip to Arizona, and this state has 5.7 daily peak sun hours or 1767 monthly. The total electrical consumption of the RV is 4848 Wh. 

First, convert Wh to kWh, so 4848Wh = 4.8kWh.

Now, apply the formula.

4.8kWh x 31 days = 148.8kWh monthly

148.8 ÷ 176,7 = 0.842 

0.842 x 1000 = 842 watts

842 ÷ 200 = 4.21

So, according to this formula, an RV with 4.8kWh electrical consumption traveling through Arizona would require X4.21 (200 watts) solar panels to fulfill the solar demand. It is recommended to round the figure to 5 as there are no half panels. 


Helpful Tips For Conserving Energy

what size solar panel for rv

Well, there is not a lot you can do to save energy consumption, especially with appliances like a coffee maker or microwave on board. One of the best ways to conserve energy is by reducing the overall electrical consumption and do not let the appliances run without a check.

Also, you must give a lot of thought before installing certain devices and appliances in the RV and ensure that they will pay off in the long run.

For example, fluorescent and LED bulbs tend to consume relatively less energy as compared to traditional incandescent bulbs. Also, they are meant to last longer, thereby saving you the cost of frequent replacements.  

You can also think about upgrading your old appliances as an old TV uses more watts per hour as compared to the advanced flat screens. Upgrading your old TV to the newer energy-efficient flat screen can help you slash down on the energy demand.

After replacing the old equipment and light fixtures, you might be able to cut down the energy requirements by 10% to 15%. 

There are a couple of other things that you can incorporate into your lifestyle to minimize energy consumption needs.

  • Disconnect the cellphone or laptop chargers when not in use.
  • Heat your coffee or other beverages over a camp stove.
  • Turn off fans or AC when you are not in the RV.
  • Try to cook the food on the outdoor grill. This will not only reduce the stove usage but also keep the interior of the RV from heating up.
  • Do not take a long shower to reduce the energy consumption by the water heater.

Frequently-Asked Questions

What size solar panel do I need for RV?

While it depends on the electrical consumption of the appliances in the RV, most of the RVs are equipped with 100-watt or 200-watt solar panels on the roof. A 200-watt solar panel is enough to run a small refrigerator and other such equipment for hours. 

What can I run off of a 100-watt solar panel?

A single 100-watt solar panel can easily power small appliances and devices like bulbs, lamps, ceiling fans, Wi-Fi routers, and laptop and cell phone chargers for hours. 

How much power will a 190-watt solar panel produce?

The 190-watt solar panels are known to be the most efficient solar panels these days. They can produce up to 9.6amps even on a 70° F sunny day. 

What can a 300-watt solar panel run?

A 300-watt solar panel, when paired with a 120Ah lithium-ion battery, can run bigger appliances like a refrigerator, microwave oven, treadmill, vacuum cleaner, blender, coffee maker, and even Desktop computer. 

Do you need batteries for your RV solar panels?

Of course, you need batteries for your RV solar panels because, without batteries, there would be no way to store the power. Solar panels convert the light energy and store it in the battery so you can use it later as electricity.

How Many Solar Panels Do I Need for Boondocking?

You should use at least two 120-watt solar panels for Boondocking. It would be enough to power certain appliances like a television, blender, vacuum cleaner, fridge, and hairdryer. 


Final Verdict: How Much Solar Power Do I Need For An RV

Your RV needs an efficient off-grid solar system to power all the appliances. You must be careful while calculating the electrical consumption requirements of the RV. This will help you accurately determine what size solar panel for RV should be picked. 

This brings us to the end of this guide. Hopefully, it provided the information you were looking for. Make sure to install energy-efficient devices and upgrade the old appliances to shave down your wattage needs. 

Happy traveling!

About the Author David Roberts

I'm a Mechanical Engineer who's obsessed with solar energy and sustainable living.

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