The short version: most weekend campers with a propane fridge are covered by 100–200W. Boondockers running a 12V compressor fridge want about 400W. Full-timers with Starlink, a laptop and a furnace fan need 600–800W, or a smaller array plus a DC-DC charger that charges while they drive. To size your own rig in two minutes, use our RV solar & battery calculator: it gives you a Renogy parts list you can add to your cart in one click.
"How much solar do I need?" has a real answer, and it isn't "as much as fits on the roof." It comes from three numbers: how much power you use each day, how much sun you get, and how many days you want to go without it. This guide works through that math, then matches the result to the Renogy kits we stock.
Step 1: add up what you use in a day
Here are typical daily figures at 12V for common RV loads. They are the same numbers our calculator uses:
| Load | Amp-hours per day |
|---|---|
| Baseline: lights, water pump, phone charging, vent fans | 18Ah |
| 12V compressor fridge | 25Ah |
| Propane (absorption) fridge, controls only | 3Ah |
| Starlink or a cell booster, on most of the day | 20Ah |
| Furnace or diesel heater running at night | 10Ah |
| CPAP overnight (add 15Ah with the heated humidifier) | 15Ah |
| TV in the evening | 8Ah |
| Laptop for work or streaming | 6Ah |
| Morning microwave or coffee maker (through an inverter) | 8Ah |
Step 2: turn daily use into panel watts
Multiply your daily amp-hours by 12.8 to get watt-hours. Divide that by your peak sun hours, then by 0.75, because real panels on a real roof deliver about three-quarters of their label rating once heat, angle, dust and wiring losses are counted. Manufacturer daily-output figures assume ideal sun, so we don't use them.
Worked example: a boondocker with a 12V fridge, TV and laptop uses 18 + 25 + 8 + 6 = 57Ah a day, or about 730Wh. In 5 hours of summer sun that needs 730 ÷ 5 ÷ 0.75 = ~200W. In 3 hours of winter or cloudy sun it needs ~325W. That is why 400W is the comfortable answer for this camper: it covers the bad days, not just the good ones.
What each array size actually delivers
| Array | 5 sun hours | 3 sun hours |
|---|---|---|
| 100W | 375Wh · ~29Ah | 225Wh · ~18Ah |
| 200W | 750Wh · ~59Ah | 450Wh · ~35Ah |
| 400W | 1,500Wh · ~117Ah | 900Wh · ~70Ah |
| 600W | 2,250Wh · ~176Ah | 1,350Wh · ~105Ah |
| 800W | 3,000Wh · ~234Ah | 1,800Wh · ~141Ah |
These figures assume a 12V system and 75% real-world harvest.
Which Renogy kit fits which camper
Weekend camper, propane fridge (about 20–30Ah a day): 100–200W
The 100W starter kit keeps a battery topped up between weekends and is rated to expand to 400W. For more margin, the 200W starter kit uses the same Wanderer Li 30A controller. The 200W Essential kit adds a flush-mount Adventurer controller and Bluetooth module for a cleaner install.
Boondocker with a 12V fridge (about 45–60Ah a day): 400W
This is the size most people should buy. The 400W kit with a Rover 40A MPPT uses four 100W panels. The 400W starter kit uses two 200W panels, which means fewer roof penetrations. If you drive most days, the 400W Essential kit with a DC-DC charger also charges from the alternator.
Full-timer or remote worker (about 80–120Ah a day): 600–800W
Starlink, a laptop and a furnace fan add up quickly. The 600W Essential kit and the 800W Essential kit (four 200W panels with a Rover 60A MPPT, mounts, fusing and Bluetooth in the box) cover this, as long as your roof has the space. A typical travel trailer fits 400–800W.
Starting from scratch, battery included
If you need the battery and inverter as well, the complete kits save matching parts yourself: 400W with 2.4kWh, 400W with 3.6kWh, 800W with 3.6kWh, or the ShadowFlux RV Solar Solution Kit in 3.8 or 7.6kWh.
Don't forget the battery
Solar refills the battery; the battery carries you through the night and the cloudy days. Size it as daily amp-hours × days without sun ÷ 0.85, since you should leave about 15% in a lithium bank. Our 57Ah boondocker wanting two days of reserve needs about 134Ah, so a Renogy Pro 200Ah is the right choice. Camping below freezing? Choose a self-heating battery such as the Rego 104Ah.
No room on the roof?
Portable panels do the same job without drilling and can be parked in the sun while the rig sits in shade. Options include the folding solar suitcase and the solar blanket.
FAQ
Can I start small and add panels later?
Yes, if you buy the controller for the array you will end up with. A 40A MPPT handles about 520W at 12V, so a 200W start can grow to 400W without replacing the controller. Our Renogy controller guide lists the limits for each model.
Will solar run my rooftop air conditioner?
Not on a normal RV roof. A 13,500 BTU unit running through the night can use more energy than 1,000W of panels makes in a day. The calculator shows you which side of that line you are on.
Does driving help?
A lot. A 30A DC-DC charger puts back about 27Ah an hour of driving, which is why people who move every day or two can run a smaller array.
Get your exact number: the RV solar & battery calculator does this math from the loads you tick and returns a matched Renogy parts list you can add to your cart in one click. Or browse all Renogy.