Is 400 Watt Solar Panel Enough for RV?

If you are a person who likes self-driving tours, you may wonder if 400 watt solar panels are enough to power your RV. After all, solar panels are an environmentally friendly, renewable and economical source of energy that can allow you to enjoy freedom and comfort on the road. But can 400 watt solar panels really meet the power needs of your RV? This depends on several factors:

  • The power consumption of your RV appliances
  • The efficiency and location of your solar panels
  • The capacity and type of your battery pack
  • The sunshine time and intensity in your area

In this article, we will introduce these factors separately and give some calculation methods and suggestions to help you judge whether 400 watt solar panels are suitable for your RV.

400 Watt Solar Panel

The power consumption of your RV appliances

Different RVs have different appliance configurations, such as lights, refrigerators, air conditioners, microwaves, TVs, etc. These appliances consume a certain amount of power, some are continuously running, and some are in intermittent use. Therefore, you need to calculate how much watt-hours (Wh) or kilowatt-hours (kWh) of power your RV needs per day.

Generally speaking, you can estimate their power consumption by looking at the power (W) and usage time (h) of each appliance. For example, if you have a 100W light bulb and use it for 4 hours a day, it will consume 400Wh or 0.4kWh of power per day.

For the convenience of calculation, you can arrange all appliances according to their power consumption from large to small and record their daily usage time. Then multiply them and add them together to get the total power consumption. For example:

Appliance  Power (W) Usage time (h) Power consumption (Wh)
Air conditioner 1500 4 6000
Refrigerator 200 24 4800
Microwave 800 0.5 400
TV 100 2 200
Lights 100 4 400
Total 11800

According to the table above, we can conclude that we need 11800Wh or 11.8kWh of power per day.

400 Watt Solar Panel

The efficiency and location of your solar panels

Solar panels work by converting sunlight into direct current electricity. However, not all sunlight can be used by solar panels, because some of it will be reflected or scattered. Therefore, solar panels have a parameter called efficiency, which indicates how much proportion of sunlight they can convert into electricity.

Generally speaking, the efficiency of solar panels is between 15% and 20%, which means that if a solar panel receives 1000W/m2 of sunlight, it can only produce up to 200W/m2 of electricity.

In addition to efficiency, the location of solar panels is also important. In order to obtain maximum power generation, solar panels should face the sun as much as possible and avoid shading or shadows. Generally speaking, the best angle is the same as the local latitude and adjusted according to the season. For example, in the northern hemisphere, in winter, the solar panels should be tilted higher to capture more low-angle sunlight; while in summer the solar panels should be tilted lower to reduce reflection losses.

For the convenience of calculation, we can assume that a 400W solar panel can produce 80W/m2 of power generation under average conditions. Then, if we have a 2m2 400W solar panel, it can produce 160Wh or 0.16kWh of electricity per hour.

400 Watt Solar Panel

The capacity and type of your battery pack

Since sunlight is an unstable and intermittent source of energy, you need a battery pack to store excess electricity and provide power when there is no sunlight. The battery pack has two important parameters: capacity and type. Capacity indicates how much electricity the battery pack can store, in amp-hours (Ah) or kilowatt-hours (kWh). Type indicates what kind of chemical substance the battery pack uses to store electricity, common ones are lead-acid, lithium-ion, nickel-hydrogen, etc. Different types of battery packs have different characteristics, such as weight, life span, price, maintenance, etc.

Generally speaking, you need to choose a suitable capacity and type of battery pack according to your RV power consumption and sunshine time. For example, if you need 2kWh of electricity per day and have 6 hours of effective sunshine time per day (assuming an average power generation of 200W/m2), then you need at least a 4kWh (or 400Ah) capacity and can withstand deep discharge (i.e., discharge and recharge) and high temperature (such as lithium-ion) type of battery pack.

The sunshine time and intensity in your area

The last influencing factor is how much and how strong sunlight your area receives per day. This depends on geographical location, season, climate, and other factors. Generally speaking, the sunshine time and intensity are higher in areas close to the equator or at high altitudes; while the sunshine time and intensity are lower in areas close to the poles or at low altitudes. In addition, the sunshine time and intensity are also higher in clear and cloudless weather than in cloudy and rainy weather.

You can check the local meteorological bureau or online data to find out the average sunshine time and intensity in your area. For example, in Beijing, China, the average sunshine time is 6.3 hours/day and the average sunshine intensity is 500W/m2.

400 Watt Solar Panel


In summary, we can use the following formula to estimate whether 400W solar panels are enough to power an RV:

Total power consumption / (Power generation * Sunshine time) = Required capacity


  • Total power consumption = How much kWh your RV needs per day
  • Power generation = How much kWh your solar panel produces per hour
  • Sunshine time = Effective sunshine time per day
  • Required capacity = How much kWh you need to store

For example,

  • If we need 11.8kWh per day
  • A 400W solar panel produces 0.16kWh per hour
  • The sunshine time is 6.3 hours/day
  • Then we need a capacity of 11.8 / (0.16 * 6.3) = 11.7kWh

Therefore, a 400W solar panel is not enough to power our RV. We need to add more solar panels or use other auxiliary power generation equipment.


If you are interested in our products and want to know more details,please leave a message here,we will reply you as soon as we can.