How to size a solar system for the RV

Getting the right size of your RV’s solar system – solar panel, battery and charge controller is key to you enjoying a comfortable life while you are out in the road or in the park.

The size of this solar system largely depends on the energy requirement of the appliances in your camper and the average number of hours per day these appliances will run for.

Calculating how many watts you need for your RV

You can use this simple calculator to get an indication of how many solar panels you need for your RV, their  combined wattage and the corresponding battery capacity (Ah) to keep your appliances running.

To use the calculator:

  • First, specify the average peak hours for a typical camping location you intend to plan for.
  • Then for each appliance category, indicate the combined wattage of the appliances in each category and the average number  of hours they will run for each day.
  • To find the rated power consumption of each appliance – check the manufacturer’s  power consumption or watt  rating label for the appliance.

For example, if you have 5 x 10W lights running for approximately 5 hours, that will be 50W for 5 hours!

The calculator then provides: the estimated total wattage of your solar panels (watts), the number of solar panels, battery capacity and charge controller capacity for your motorhome.

For example – using the calculator, an RV with the appliances listed below running for the indicated hours on average:

  • Combined lighting: 50W for 5 hours
  • Combined computer: 40W for 5 hours
  • Fridge: 100W for 5 hours

You would  need approximately 3 x 100W solar panels, either a 158 Ah AGM battery or 58 Ah Lithium battery.

Note.  Use the next available standard size of solar panel or battery available.

To find charge controller size, check out the charge controller sizing calculator.

Related Topics

How many solar panels do I need to run a fridge ?
How many solar panels do I need for 2000 kWh?