RV Solar Calculator
Size a complete off-grid electrical system for a motorhome or camper: solar array, battery bank, charge controller, inverter, cable and fuses, with a cost estimate. Enter what you actually run and the calculator does the rest.
The engineering is the same for an RV as for a van. What differs is scale. RVs carry bigger fridges, more lighting, often air conditioning, and a great deal more roof to put panels on.
Typical RV builds compared
Each row is computed from the preset loads for that class, at 4.5 peak sun hours with two days of LiFePO4 reserve.
| RV class | Daily use | Solar | Battery | MPPT | Est. cost |
|---|---|---|---|---|---|
| Class B (camper van) | 1,025 Wh | 304 W | 214 Ah | 40 A | $1,200–$3,450 |
| Class C | 1,655 Wh | 491 W | 345 Ah | 60 A | $1,705–$4,997 |
| Class A (motorhome) | 2,815 Wh | 835 W | 587 Ah | 100 A | $2,630–$7,835 |
- Class B (camper van): Van chassis, compact. Closest to a self-build van in load and roof space.
- Class C: Cab-over on a truck chassis. More appliances, more roof, often a TV and a bigger fridge.
- Class A (motorhome): Largest rigs, residential fridge and often air conditioning. Roof space is rarely the limit.
The calculator below is preset with the Class C loads. Change the appliances, location, season and cable length for your own rig and everything recomputes live.
Quick start with a profile:
Your daily loads
Add each device with its watts and hours per day.
No loads yet. Add your fridge to start, or pick a profile above.
Solar array
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Add loads to size your array.
Show the math
Battery bank
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Show the math
Charge controller (MPPT)
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Show the math
Inverter
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Show the math
Battery-to-inverter wire & fuse
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Show the math
Estimated cost
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Budget street price → premium brands.
Itemized breakdown
Embed
Free to use on your own site — just keep the credit link. Sizing and options.
Where RVs differ from vans
More roof, fewer constraints. A Class A roof rarely limits the array. On a van, roof area is usually the binding constraint, which is covered in how many solar panels fit on a van roof.
Air conditioning changes everything. A rooftop unit draws 1,200 to 1,800 W running, which is a generator or shore-power load rather than a solar one. See running air conditioning on solar.
Residential fridges cost more than compressor fridges. A residential unit through an inverter can double the fridge line in your budget.
Related
Frequently asked questions
＋ How much solar does an RV need?
It depends on the class and how you travel. A Class B camper van typically needs 400 to 600 W, a Class C around 600 to 800 W, and a Class A with a residential fridge and entertainment often 800 W or more. Enter your own appliances rather than relying on a class average, because two identical rigs can differ by a factor of two.
＋ What size battery do I need for an RV?
Multiply your daily watt-hours by the days of reserve you want, then divide by system voltage times depth of discharge (0.8 for LiFePO4). A Class C using about 1,650 Wh a day with two days of reserve needs roughly 345 Ah at 12V. The calculator does this and compares LiFePO4 against AGM.
＋ Is this calculator different for RVs and vans?
The engineering is identical, so the same tool sizes both. What changes is scale: RVs usually have larger fridges, more lighting, air conditioning and considerably more roof area, so the numbers come out higher. The presets on this page reflect typical RV loads rather than van loads.
＋ Can solar run an RV air conditioner?
Running an air conditioner on solar alone is impractical for most rigs. A rooftop RV air conditioner draws 1,200 to 1,800 W while running, which would need a very large array and battery bank to sustain. Most owners run air conditioning from shore power or a generator and use solar for everything else.