Hey everyone! I'm just starting out with solar energy and need some help figuring out the right size for my system. Since my family and I often travel in an RV, we're planning to set up solar to support about 40 watts of continuous power around the clock. I know that includes a solar panel, battery bank, and inverter, and I'm aware there are losses at each stage. I'd like to have as close to 24 hours of uptime as possible, with a setup that's not too heavy but can be easily managed by one or two people. How big does my system need to be to reliably provide 40W? I'm thinking maybe around 160W to account for storage and inefficiencies, but I'm not sure if that's enough or if I should aim for more. Any advice based on your experiences would be greatly appreciated!
3 Answers
In my RV, I utilize about that much power daily—around 960 watt-hours for true 24/7 usage. With 350 watts of solar panels and a 100 amp-hour LiFePO4 battery, I can fully charge it daily with a couple of hours of good sun. However, two or three cloudy days can be a challenge, so you might want to keep that in mind when managing your power.
For a starter system, I’d recommend considering around 400 watts of solar power. If you're savvy with setup, something like an eco flow battery paired with 400 watts can really cover your needs! I went a different route and bought everything separately, and while it was a fun project, I’m not sure I saved much money overall. Just keep in mind your skill level when planning this out!
First, calculate your daily power needs. So for 40W running 24/7, that's 960Wh per day. Depending on your location and the sun's strength, you'd want 320W minimum for sunny days, but realistically you should aim for 600-900W to cover those cloudy days. Also, consider having about three times your daily needs in storage for better reliability. Just remember that in an RV, you can also charge from the vehicle if conditions are tough!