Best 300-Watt Solar Panels: Cost, Specs & Everything You Need to Know

Here’s what you’ll learn in this guide:

  • The best 300-watt solar panels on the market
  • What a 300-watt solar panel can power
  • How much you might pay for this size of the panel
  • 300-watt panel specs
Ecowatch Author Dan Simms

By Dan Simms, Solar Expert

Updated 8/2/2022

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While choosing to go solar is a great way to reduce your energy bills and the strain you place on the environment, deciding which panels best suit you and your budget can be challenging. You need to think about the brand, size, power output and much more to ensure your panels meet your energy needs and are affordable. 

In this comprehensive guide to 300-watt solar panels, we’ll review the best panels in this size range, overall cost, the power output you can expect, and more.

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Jump To: What Are the Best 300-Watt Solar Panels? | Panel Pricing | Warranties | Panel Specs | How Much Energy Will a 300-Watt Solar Panel Produce? | What Can a 300-Watt Solar Panel Run? | What Factors Influence Power Output? | How Many 300-Watt Solar Panels Do I Need?

What Are the Best 300-Watt Solar Panels Available?

Most solar panels made for residential customers are larger than 300 watts, but there are plenty of manufacturers who make this size solar panels for RV solar installations, solar applications on boats, light residential use, and more. Below are our top-rated solar panels in the 300-watt size class.

  • Our Top Pick for High Efficiency: Renogy RNG-300D 320-Watt Monocrystalline Solar Panels
  • Best for Off-Grid Use: WindyNation 300-Watt Solar Panel Kit
  • Best Value: Grape Solar GS-M60-300-US 300-Watt Solar Panels
  • Most Affordable: ACOPOWER 300W Polycrystalline Solar RV Kit
  • Best Portability: DOKIO 300W Portable and Flexible Solar Panel Kit

300-Watt Solar Panel Pricing

Solar panels — even smaller ones that are meant for light use, like 300-watt panels — can quickly get expensive and push you over your budget. While renewable energy will generally save you money on electricity costs, in the long run, optimizing your panel selection to suit your budget will always be important.

The table below provides a side-by-side pricing comparison of the top five 300-watt solar panels available. Keep in mind that the prices reflected below are very likely not the total you’d pay for fitting home or even an RV with solar panels, as the production from a single panel would be far too low.

Solar Panel Price Per Panel Total Price
Renogy RNG-300D 320-Watt Monocrystalline Panels $324.99 $1,299.99 (includes four panels)
WindyNation 300-Watt Solar Panel Kit $480.67 $1,442.60 (includes three panels, controller, inverter, and three 100 amp-hour batteries
Grape Solar GS-M60-US 300-Watt Solar Panels $321.18 $1,284.73 (includes four panels)
ACOPOWER 300W Mono Solar Panel RV Kit $169.00 $506.99 (includes three panels and MPPT charge controller)
DOKIO 300W Portable Solar Panel Kit $314.00 $314.00 (includes one foldable solar panel and solar charge controller)

300-watt solar panel warranty tip

300-Watt Solar Panel Warranties

With the high prices, you’ll pay for solar panels, it’s important that you look for brands and solar module options that include warranty coverage. Some smaller panels are rated to last for a decade or more, and the companies that stand behind their products will not only instill confidence when you’re shopping, but they’ll also protect you from having to replace your equipment shortly after buying it. Many companies include shorter warranties that cover your equipment for just a few years.

Unfortunately, many of the major solar manufacturers — like SunPower, Tesla, and Panasonic — no longer make 300-watt panels, as advancements in solar technology have led them to focus on higher-production panels largely for on-grid applications. These larger companies more often have lengthy warranties, so the coverage you’ll find for smaller panels will be limited in most cases. The table below provides warranty information for the top five 300-watt solar panels we’ve mentioned above.

Solar Panel Warranty Coverage Included
Renogy RNG-300D 320-Watt Monocrystalline Panels 10-year warranty for materials and workmanship
WindyNation 300-Watt Solar Panel Kit 1-year manufacturer’s warranty
Grape Solar GS-M60-US 300-Watt Solar Panels 10-year limited product warranty plus 10-year warranty for 90% output and 25-year warranty for 85% output
ACOPOWER 300W Mono Solar RV Kit 5-year workmanship warranty plus 25-year warranty for 85% output. The charge controller comes with 1-year limited warranty
DOKIO 300W Portable Solar Panel Kit 1-year warranty

Panel Specifications: How Big Is a 300-Watt Solar Panel?

The size of your 300-watt solar panel will depend on the specific model and manufacturer, as the number of solar cells used and the size of those cells will affect the dimensions. That being said, the average size for a 300W solar panel is around 36 inches by 65 inches. Panels created with DIY solar systems in mind tend to be made with aluminum frames and are kept at a lightweight for easy maneuverability. The table below includes dimensions for the top five brands we’ve mentioned above.

Solar Panel Product Dimensions (Per Panel) Panel Weight (Per Panel)
Renogy RNG-300D 320-Watt Monocrystalline Panels 39.4” by 65.6” at 1.4” thick 9.93 lbs
WindyNation 300-Watt Solar Panel Kit 21.25” by 39.17” at 0.98” thick 13.3 lbs
Grape Solar GS-M60-US 300-Watt Solar Panels 39.25” by 65” at 1.5“ thick 10.75 lbs
ACOPOWER 300W Mono Solar RV Kit 20.1” by 40.2” at 1.4” thick 12.78 lbs
DOKIO 300W Portable Solar Panel Kit 21” by 52” at 0.98” thick (unfolded) 17 lbs

How Much Energy Will a 300-Watt Solar Panel Produce?

It’s challenging to say with certainty how much energy a 300-watt solar panel will produce, as production can be influenced by many things. Factors to consider include the brand of the panel you have, the efficiency for which that brand is rated, the intensity of the sunlight hitting your panel, how many hours of sun your panel receives every day, the direction your panel faces, and more.

With that being said, you can use the calculation below to help you determine how much power your panels will produce:

  1. (average hours of sunlight) x (solar panel wattage) x (75% maximum power production to account for changing weather conditions and lower sun intensity in the morning and afternoon) = your daily watt-hours
  2. (your daily watt-hours) / 1,000 = your daily kilowatt-hours (kWh) per panel

How Many kWh Does a 300-Watt Solar Panel Produce?

If you assume you average around six hours of sunlight per day, your calculation would be as follows:

(6 hours of sunlight) x (300 watts) x (75%) = 1,350 watts per day

(1,350 watts per day) / 1,000 = 1.35 kWh per day

If your area experiences the same average sunlight year-round, one 300-watt solar panel could produce around 492.75 kWh per year. This calculation can often be used to determine how many panels you’ll need in total for your solar project, which we’ll discuss in greater depth further down.

How Does Solar Irradiance Impact Power Output?

Solar irradiance has a massive effect on a solar panel’s output. The term “solar irradiance” refers to the intensity of the sun at a given spot on earth. The greater the intensity or brightness of the sun in your area, the more output you’ll see from your panels for a given number of sunlight hours. A higher level of solar irradiance will typically lead to greater solar power production overall, regardless of the size or rated output of your panels. This is especially important for homeowners or DIY solar installers who experience cloudy weather or shade often.

Additionally, homeowners in states that are closer to the equator will experience a higher level of solar irradiance, as the sun hits these areas more directly. A 300-watt solar panel will tend to produce more solar energy in states like Texas, Oklahoma, Arizona and Florida than the same panel would in a northern state where the sunlight is less intense. Solar irradiance is an important factor to consider when sizing your solar project because it can often help determine how many panels you need and help avoid an undersized solar array.

Here’s a look into solar irradiance:

Is Panel Voltage Important?

Yes, solar panel voltage is important, although it’s an often-overlooked measurement when it comes to solar equipment. When discussing voltage, it’s often easiest to think of a water tank with a pipe connected to the bottom. The higher the water tank and the more water is contained within it, the faster the water will travel down and out of the pipe. Voltage works similarly, and your panels won’t charge your batteries or power your devices if your voltage is too low.

For example, many solar panels have a voltage of between 15 and 18 volts per panel. This is high enough to charge a 12-volt battery bank or supply power for something that uses 12 volts. Solar panels can be set up in series — often using branch connectors — to provide higher voltages for running multiple electronics at once — like in the case of a residential solar panel system — or to charge larger, higher-voltage batteries — like solar batteries or other power banks that run at 24 volts or more.

What Can a 300-Watt Solar Panel Run?

A single 300-watt solar panel can be used to run quite a few different small appliances and electronics. The table below provides a list of some of the most common household items homeowners run using a 300-watt solar panel.

Appliance/Household Item Running or Rated Watts Required to Run
Ceiling Fan 60 watts
Vacuum Cleaner 200 watts
PC (Non-Gaming) 240 watts
Small Dehumidifier 250 watts
Rice Cooker 200 watts
Heated Blanket 200 watts
TV 230 watts
Crockpot 250 watts
DVD Player 100 watts
Laptop Charger 125 watts
Projector 280 watts
Phone Charger 10 watts
Mini-Fridge 100 watts
Gaming Console 180 watts
Hair Straightener 120 watts
Electric Can Opener 170 watts
Home Speaker System 100 watts
Paper Shredder 225 watts

What Factors Influence Solar Panel Power Output?

Above, we mentioned that it’s challenging to determine the expected power output for your solar panels, even if you know the wattage and voltage. Solar power systems rely on available sunlight for power generation, so changes in the availability of sunlight — which occur frequently throughout the day — will have an impact on your rate of production.

For example, the weather can decimate your power production if clouds block the sun. The intensity of the sun on your property will affect generation, and this can change from season to season, depending on where you live. The direction your solar panels face will have an impact on your production, as panels that face the sun for more hours during the day will receive more sunlight for energy generation.

The type of panel and the rated efficiency over time can affect your power production, especially as your panels’ age. Finally, shading on your property can prohibit sunlight from reaching your panels at certain times of the day, so homeowners with tree coverage or shade from neighboring homes or buildings will naturally see a lower rate of production than those with unimpeded sunlight hitting their panels.

How Many 300-Watt Solar Panels Do I Need?

You can determine the number of solar panels you need by calculating how many kilowatt-hours (kWh) your home uses each year and dividing by the estimated production of each panel. For example, a single 300-watt solar panel in an area that receives six hours of sunlight each day will produce approximately 492.75 kWh per year. If you can calculate how much energy you consume annually, you can divide by this number to determine how many 300-watt panels you need.

According to the U.S. Energy Information Administration (EIA), the average home in the U.S. consumed 10,715 kWh in 2020.1 If you planned on using Renogy 300-watt panels to power your home, for example, you could use the below calculation to figure out how many panels you’d need for a 10kW solar system:

(10,715 kWh used annually) / (492.75 kWh produced per 300-watt panel) = 21.75, or 22 panels

Keep in mind that this calculation assumes that your property receives six hours of sunlight per day and that your home uses the average amount of electricity. Your numbers could vary, so it’s best to calculate using numbers that accurately reflect your home energy consumption and climate. At 22 panels required, 300-watt panels aren’t used for homes as often as larger ones. The best panels for homes are generally rated for higher production, meaning you’ll need fewer panels on your roof to maintain the required level of energy production.

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Dan Simms

Solar Expert

Dan Simms is an experienced writer with a passion for renewable energy. As a solar and EV advocate, much of his work has focused on the potential of solar power and deregulated energy, but he also writes on related topics, like real estate and economics. In his free time — when he's not checking his own home's solar production — he enjoys outdoor activities like hiking, mountain biking, skiing and rock climbing.