What an RV day actually costs
Much less than people expect, as long as the roof unit stays off.
| Load | Typical draw | Per day |
|---|
| 12V compressor fridge | 40–60 W cycling | ~400 Wh |
|---|
| LED lighting | 30–60 W | ~200 Wh |
|---|
| Water pump | 50–100 W intermittent | ~50 Wh |
|---|
| Laptop and devices | 45–90 W | ~350 Wh |
|---|
| Fan overnight | 20–40 W | ~250 Wh |
|---|
| Roof AC, 13,500 BTU | 1,200–1,700 W running, 3,000–3,500 W starting | Thousands of Wh |
|---|
Rows other than the air conditioner are working estimates from typical equipment ratings and duty cycles rather than measurements. The marked row is the one that changes the purchase entirely, and its starting figure is the industry-standard sizing basis for RV generators.
Everything above the marked row totals roughly 1,000–1,400Wh. A 1,024Wh battery covers most of that and a 2,048Wh one covers two days.
The air conditioner is a different purchase
A 13,500 BTU roof unit typically needs 3,000–3,500 starting watts. That exceeds the inverter rating of every portable battery in this class, and even if it started, its 1,200–1,700W running draw would empty a 2,000Wh station in about an hour.
The honest options are:
- Shore power. The simplest answer, and free at most sites.
- A 3,500W-class inverter generator. The conventional RV solution, and why that size exists.
- Two small inverter generators in parallel. Quieter and easier to carry than one large machine.
- A soft-start device on the air conditioner. Reduces the starting surge substantially and can bring it inside what a smaller generator handles. Fitted to the AC, not to the battery.
What is not an option is a bigger folding panel. Solar refills a battery over a day; it does not carry an air conditioner in real time.
Battery versus RV generator
| Power station | Inverter generator |
|---|
| Campground rules | Permitted everywhere, any hour | Often restricted to set hours, sometimes banned |
|---|
| Noise | Around 30 dB under load | 48 dB(A) at best, usually more |
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| Fuel in the vehicle | None | Gasoline or propane, stored and rotated |
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| Can be used inside | Yes | Never |
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| Roof air conditioner | No | Yes, at 3,500W class |
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| Multiple overcast days | Limited by capacity | Limited only by fuel |
|---|
The 30 dB and 48 dB(A) figures are manufacturers' published numbers under their own test conditions. Because decibels are logarithmic, that gap is much larger than it looks.
Solar sizing for an RV
For a daily use of roughly 1,000–1,400Wh, a rough rule gets you close: a panel rated at about a third of your daily watt-hours will keep pace in good summer conditions.
Which lands around 400W of panel — two 200W folding panels, or one 220W panel accepting that you will draw the battery down slowly across a stretch of poor weather.
Check your station's maximum solar input in both watts and volts before buying panels. The full solar arithmetic and the connector guide cover the details.
The arrangement that works
A mid-sized battery inside the vehicle, one or two folding panels, and a small inverter generator only if you genuinely need air conditioning or travel in the shoulder season.
That combination is legal at more sites, silent overnight, produces no exhaust in a small sealed space, and gives you a unit that is also a capable home backup battery for the eleven months a year you are not travelling.
The camping and RV scenario page works through the tiers by budget.
