Whether you’re boondocking deep in the Arizona desert or camping near the mountains, a properly sized solar system can be the difference between total independence and constant power anxiety.
RV solar panels allow you to stay off-grid longer without relying on noisy generators or hookups. But to get the most out of your solar setup, you need to choose a system that’s right for your energy needs, your RV size, and your lifestyle on the road.
This guide will walk you through the process of sizing your solar system accurately using trusted Dometic components. Whether you’re a weekend camper or a full-time RVer, you’ll learn how to calculate usage, choose the right panels and batteries, and future-proof your setup.
Why Proper RV Solar Sizing Matters
Installing RV solar panels is an investment. If you install too little, you’ll run short on power. Too much, and you may waste money or overload your roof space. A well-sized solar system will give you enough energy for daily essentials without overspending on components you don’t need.
When your RV solar system is correctly sized you’ll experience:
- Reliable power for lights, fans, and devices
- Fewer trips to recharge or plug in
- Less noise and fuel use compared to a generator
- Peace of mind knowing your energy is clean and solar efficiency
Dometic’s RV solar products are built to scale, making it easier to design a system that fits your needs now—with room to grow later.
Step 1: Determine Your Daily Power Usage
Every solar system starts with understanding how much energy you use on a typical day. This gives you a baseline for what your solar panels need to generate and what your battery bank needs to store.
Create a List of Appliances and Devices
Start by writing down everything you use in your RV each day. Then note how long you use each item and how many watts it draws.
Here is an example:
- LED interior lights – 5 watts each x 6 lights x 5 hours = 150 Wh
- Water pump – 60 watts x 0.5 hours = 30 Wh
- Laptop – 60 watts x 3 hours = 180 Wh
- 12V fridge – 40 watts x 24 hours = 960 Wh
- Phone chargers, fans, router – varies, estimate ~200 Wh
Approximate daily usage: 1,500–1,800 watt-hours (Wh)
If you use an inverter to run appliances like a coffee maker or microwave, don’t forget to include those as well—just remember that inverters are less efficient and can draw significant extra power.
Step 2: Understand RV Solar Output
Solar panels are rated in watts, but their actual output depends on how much sunlight they receive. A 200W panel might generate 1,000Wh (or 1 kilowatt-hour) per day under ideal conditions. But clouds, shading, angle, and time of year can all affect output.
Average Solar Production by Location
Sun exposure varies widely depending on where you travel. Here’s a general estimate of daily sun hours by region:
- Arizona and Southwest US: 5–6 sun hours/day
- Midwest and Rockies: 4–5 sun hours/day
- Pacific Northwest: 2–4 sun hours/day
To estimate daily solar output:
- 100W panel × 5 hours sun = 500 Wh/day
- 200W panel × 5 hours sun = 1,000 Wh/day
- 400W system × 5 hours sun = 2,000 Wh/day
Use this as a planning tool to match your energy needs to your panel capacity.
Step 3: Match Production to Your Power Usage
Once you know your daily energy use and expected solar output, it’s time to compare the numbers. If you use 1,500 Wh per day, your solar system should produce at least that much—preferably with a 10–20% buffer for cloudy days or higher-than-average usage.
For example:
- Usage: 1,500 Wh/day
- Panel Output: 2 x 200W Dometic panels = 2,000 Wh/day
That gives you enough power to meet your needs and a cushion for unexpected use. If you plan to park in shaded areas or travel during winter, consider adding a third panel.
Step 4: Size Your Battery Bank
Your solar panels charge your batteries, and your batteries power your RV. That means your battery bank must store enough energy to meet your needs when the sun isn’t shining.
Battery capacity is typically rated in amp-hours (Ah). You can convert watt-hours to amp-hours using this formula:
Watt-hours ÷ System Voltage (usually 12V) = Amp-hours
Example:
- 1,500 Wh ÷ 12V = 125 Ah
But since you don’t want to fully drain your batteries, you should aim for a bank that can store 150–200Ah of usable power.
Why Lithium Batteries Make Sense
Dometic’s lithium batteries are ideal for solar RV systems because they offer:
- Up to 90% usable capacity (vs. 50% for lead-acid)
- Lighter weight and smaller footprint
- Faster charging and better efficiency
- Built-in protection and monitoring systems
One 200Ah Dometic lithium battery could power most off-grid RV setups for a day or two without recharging.
Step 5: Consider Your Travel Style
Not all RVers need the same amount of power. Your setup should reflect how, where, and how often you travel.
- Weekend Warriors: 100–200W of solar with one 100Ah battery may be enough
- Seasonal Travelers: 300–400W solar with 150–200Ah battery bank is a great mid-range solution
- Full-Timers or Remote Workers: 500–800W solar with 300Ah+ battery bank allows for greater energy freedom
If you like to camp off-grid often or work from your RV, err on the higher side. With Dometic’s modular kits, you can always add panels later.
Step 6: Use a Quality Charge Controller
Your charge controller regulates how solar power flows into your batteries, keeping everything safe and efficient. Dometic systems come with MPPT (Maximum Power Point Tracking) controllers, which are more efficient than PWM versions—especially in low light or partial shade.
An MPPT controller will help you harvest every watt your panels produce and extend the life of your batteries.
Step 7: Plan for Expansion
One of the best features of Dometic’s RV solar products is their modularity. You can start with a basic setup and add more panels, batteries, or even a second charge controller as your energy needs grow. Planning for expansion up front saves time, money, and hassle later.
Working with a professional installer for solar for RV living can make a big difference. They’ll help design a system that fits your current energy usage while preparing for future upgrades—without overcomplicating things.
When planning your initial system, consider:
- Leaving extra roof space or mounts available for additional solar panels
- Selecting wiring, fuses, and connectors rated for higher future capacity
- Choosing a charge controller that can handle added wattage down the line
- Mapping out battery storage locations to accommodate more amp-hours later
By involving a professional, you can ensure your system is expandable and code-compliant from the beginning—making every upgrade easier when the time comes.
Dometic RV Solar: Built for Arizona and Beyond
Dometic is a leader in RV solar innovation, with products specifically designed for mobile, off-grid lifestyles. Their panels, batteries, and controllers are tested in rugged environments and optimized for ease of use, scalability, and efficiency.
Benefits of choosing Dometic:
- Expandable plug-and-play kits
- Efficient monocrystalline solar panels
- Lithium iron phosphate (LiFePO4) battery systems
- MPPT controllers for max output
- Trusted performance in harsh environments like Arizona
Whether you’re chasing sunsets across the Southwest or exploring national forests, Dometic solar solutions are ready to power your journey.
Sizing RV Solar the Right Way
Getting your solar setup right doesn’t need to be complicated. Once you understand how solar works, how much energy you use, how much power you can collect from the sun, and how much you want to store, the rest is about finding the best fit.
Dometic’s high-quality solar products take the guesswork out of sizing. And with the ability to start small and scale up, you’ll never be stuck with a system that’s too big—or too small—for your next adventure.
FAQs
How many solar panels do I need for my RV?
The average RVer can start with 200–400 watts of solar, depending on usage. Full-time travelers may need 600 watts or more to power appliances, devices, and daily living needs.
Can I run my RV air conditioner with solar?
Most rooftop AC units draw too much power for solar alone. However, solar can support everything else—lights, fans, fridge, electronics—and reduce your generator usage significantly.
What type of battery is best for RV solar?
Lithium batteries (LiFePO4) are the best choice for most RVers due to their efficiency, longer lifespan, and deeper discharge capabilities.
Is it easy to install an RV solar system?
Dometic offers user-friendly solar kits with everything included. Many RVers install them DIY, but our professionals can help with complex or roof-mounted systems.
Can I upgrade my system later?
Yes! Dometic solar systems are designed to grow with you. Add more panels, batteries, or even upgrade your controller as your needs evolve.
