How Much Solar Power Do I Need for RV in 2024?

Introduction

Wondering how much solar power your RV really needs? With all the different numbers out there, figuring out the right solar setup can feel like a puzzle. But don’t worry! Whether you're planning weekend trips or long-term off-grid living, I’ve got you covered. In this guide, you will learn everything from calculating your power needs to choosing the right number of solar panels and batteries for your dream RV setup.

Power Consumption of RV appliances

To size your RV solar power system accurately, it’s essential to understand the daily energy consumption of your RV appliances. Here’s a rough estimate of the daily energy usage for common RV appliances:

Your refrigerator is cycling on and off throughout the day, so we can't just multiply rated wattage by 24 hours. As a rule of thumb, to get the real watt per hour figure, we need to divide rated wattage by 3.

How to Calculate Your Specific Power Needs

Now that you know what each appliance consumes, let’s calculate how much power your specific setup requires. It’s all about math—don't worry, I’ll keep it simple.

Here’s the basic formula:

Daily Watt-Hours (Wh) = Wattage of Appliance × Hours of Use per Day

To figure out how many amp-hours (Ah) your off-grid RV battery system will need, just divide the total watt-hours by your battery’s voltage. Most RV systems run on 12 volts, so the formula becomes:

Daily Amp-Hours (Ah) = Daily Watt-Hours (Wh) ÷ 12V

For example, if your fridge uses 2400Wh per day, here’s how you calculate it:
2400Wh ÷ 12V = 200Ah

This means your fridge alone will use around 200Ah of battery capacity per day. Repeat this calculation for each appliance, and you’ll have a good idea of your RV solar power consumption.

Alternative Method: Use RV Battery Monitor to Measure Actual Usage

If you have a battery bank in your RV, you can easily check your energy use. Instead of guessing how much power you're using, you can measure it.

Go camping and use a battery monitor to track your energy use for 24 hours. This way, you will know exactly how much energy your RV uses in a day. You can use this information to plan your solar setup better.

A battery monitor records the amount of energy drawn from your batteries, helping you make data-driven decision about the size of your solar system without relying solely on estimates.

Review your 24-hour consumption and base your solar panel requirements on this real data, taking into account any variations in weather or appliance usage.

Typical Off-Grid Solar Systems

1. Minimal Power Setup (Fridge on Propane, No AC)

If you're not ready for big investments yet, or you don't need a lot of power you can always go with a minimal solar setup. In this scenario your refrigerator will be running on propane to save solar power, and lower the system's price. Here is a rough usage estimate:

• Lights: 250Wh
• Laptop: 150Wh
• Phone Charger: 30Wh
• Water Pump: 25Wh
• Microwave: 160Wh
• TV: 120Wh
• Hotspot: 240Wh
• Coffee Maker: 100Wh
• Fan: 90Wh

Total daily consumption:
250 + 150 + 30 + 25 + 160 + 120 + 240 + 100 + 90 = 1165Wh

So, with a minimal setup you'd need about 1165Wh of daily solar generation.

2. Mid-sized Setup with Solar-Powered Refrigerator

If you're more serious about solar the next obvious thing to convert to green energy is your fridge.
For this scenario I will assume the same usage as before but with a refrigerator on top of it.

Your refrigerator is cycling on and off throughout the day, so we can't just multiply rated wattage by 24 hours. As a rule of thumb, to get the real watt per hour figure, we need to divide rated wattage by 3.

• Fridge: 2400Wh
• Previous consumption: 1165Wh

Total daily consumption with refrigerator:
2400 +1165 = 3565Wh

3. Large Solar System with Air Conditioner

Now let’s add an air conditioner into the mix. Rooftop RV air conditioner usually uses about 1500W.
We won't go into RV air conditioning viability in this article, but you can learn more about is solar powered air conditioning worth it for RVs here.

If you run it for six hours a day, that’s:
1500W × 6 hours = 9000Wh

Add that to the previous total of 3395Wh from your other appliances:
3565Wh + 9000Wh = 12565Wh

In this scenario, you’d need around 12565Wh of solar generation per day to run your air conditioner, refrigerator and other appliances.

Losses and Inefficiencies to Account For

Now that we’ve covered the basic math, let’s discuss inefficiencies and losses. Your solar panels aren’t 100% efficient, and neither are your batteries nor inverters. Here’s what to consider:

• Solar Panel Efficiency: While a 100W panel might theoretically produce 100W in direct sunlight, real-world conditions, such as the angle of the sun or cloudy weather, reduce efficiency. A 100W solar panel sitting flat on the roof will typically produce about 360Wh per day.
• Inverter Efficiency: Unlike with DC power, if you’re running AC appliances, remember that your inverter is typically 95% efficient. So, for every 100Wh your appliance requires, you’ll use around 105Wh.
• No-Load Draw: If you leave your inverter on all day, it will consume power even when it’s not actively running appliances. This no-load draw can be around 25W per hour, or 600Wh per day. Just to keep the lights off.

Don't forget to take these inefficiencies into your calculations to avoid running out of energy during your off-grid RV solar setup.

How many solar panels for RV do I need?

As a rule of thumb, a 100W solar panel sitting flat on the roof produces around 360Wh per day.
Let's calculate how many panels you'll need to power each of our examples:

Example 1: 1165Wh ÷ 360Wh = 3.24 panels
So to comfortably cover basic needs you'll need about 4 × 100W solar panels.

Example 2: 3565Wh ÷ 360Wh = 9.9 panels
So, you’d need about 10 × 100W panels to power your fridge with solar energy.

Example 3: 12565Wh ÷ 360Wh = 34.9 panels
That’s about 35 × 100W panels to run your air conditioner off-grid regularly.

Pro tip: Solar panels are only about 10-25% efficient in cloudy weather, so ideally you should have slightly more. If possible, 20% cushion is good, to account for less-than-ideal conditions.

What if I can't fit that number of solar panels on my RV roof?

You've got a few options in that case:

• Use portable solar panels: Just set them up outside, point at the sun and enjoy additional power. For smaller setups you could use portable panels exclusively, without mounting anything on your roof.
• Run backup generator: A great solution for rainy days or for when you require just a little more juice to keep the batteries charged.
• Improve RV insulation: The cold escapes through the RV walls fairly easily, especially when it has to be exposed to the sun all day. A better insulation will make your system run more efficiently and safe your roof space.

How to Calculate Battery Capacity for RV Solar Off-Grid

Convert Watt-Hours (Wh) to Amp-Hours (Ah)

Going back to our daily usage calculations, we need to convert Watt-Hours (Wh) to Amp-Hours (Ah) to determine the battery capacity needed to cover your daily usage. Here’s the formula:

Amp-Hours (Ah) = Watt-Hours (Wh) / Battery Voltage (V)

Let's calculate battery capacity we would need for our examples:

Example 1: 1165Wh ÷ 12V ≈ 100Ah

Example 2: 3565Wh ÷ 12V ≈ 300Ah

Example 3: 12565Wh ÷ 12V ≈ 1050Ah

But we’re not finished yet.

Account for Depth of Discharge (DoD)

Batteries are not designed to be fully discharged as it damages them. You should always have a battery monitor for solar system to prevent deep discharge and keep your batteries healthy, so they serve you longer.

I covered which battery type is better for your RV in my previous article.
As a quick recap, lithium batteries can be discharged up to 80%, while lead-acid batteries should only be discharged to 50%. To account for this, adjust the required battery capacity based on your battery type:

• Lithium Batteries: Divide required Ah by 0.8
• Lead-Acid Batteries: Divide required Ah by 0.5

Let’s calculate the required battery capacity based on the previous examples:

Example 1:

• Lithium: 100Ah ÷ 0.8 = 125Ah
• Lead-Acid: 100Ah ÷ 0.5 = 200Ah

Example 2:

• Lithium: 300Ah ÷ 0.8 = 375Ah
• Lead-Acid: 300Ah ÷ 0.5 = 600Ah

Example 3:

• Lithium: 1050Ah ÷ 0.8 = 1312Ah
• Lead-Acid: 1050Ah ÷ 0.5 = 2100Ah

This should give you a good idea of how much battery capacity you need to support your energy demands off-grid, depending on the battery type you choose.

Bringing it all together

The table below summarizes all the data we calculated for each setup. It should help make planning your RV solar system more straightforward!

FAQ

Can I have too much solar on an RV?

Yes, but it's all about balance. You can't sell excess power to the electric grid like you could with a home solar system. If you go too large — you may be wasting money. Too small, and you may run out of energy when it's needed. Calculate your consumption carefully, and you'll be in a great starting point.

Are solar panels worth it on an RV?

Definitely, if you love boondocking. Solar panels eliminate the need to pay camping fees and allow you to camp where you want to. Because of this RV solar systems payoff quickly.

Conclusion

Calculating the right amount of solar power for your RV doesn't have to be overwhelming. It all comes down to understanding your energy consumption and matching it with the appropriate system size. Now it's your turn—take the next step, plan your off-grid adventure, and build the perfect solar system for your RV!

Have any questions? Feel free to contact us!