300 watt Solar Panel: Output (Amps, volts), & What Can It Run?

In this post, you’ll learn how much power you can expect from a 300-watt solar panel in the real-life world and what you can power with it. 

I did an experiment with my 200-watt solar panel, which I’m gonna use as a reference or baseline.

Need a simple solution? Use the calculator given below to find out how much energy a 300-watt solar panel will produce on average per day in your city. 

Solar Panel Output Calculator

Total Solar Panel System Size
Peak Sun Hours (Per Day)
Output in (Per Day, Month, Or A Year)

The number of peak sun hours are not the number of total sunlight hours, keeping reading i’ll explain in a bit.

Calculator Assumptions

  • The results are based on 30 days of average output (some days the output energy will be higher and somedays it’ll be lower, considering the fact of changes in weather conditions, power losses due to charge controller, DC wires, solar cells inefficiency because of dirt, and the tilt angle)

For more in-depth information read this post, in which i have shared some tips to increase the output of your solar panel

Before going further watch this video to understand the basics of electricity units like amps, volts, watts

How Much Power Does A 300 Watt Solar Panel Produce

How Much Power Does A 300 Watt Solar Panel Produce
How Much Power Does A 300 Watt Solar Panel Produce

A 300-watt solar panel will produce 300 watts of power output under ideal conditions (1kw/m2 of sunlight intensity, & 20oC temperature) but in real-world situations, on average, a 300-watt solar panel will produce about 240 watts of power in a peak sun hour. 1.2kWh energy per day (considering 5 hours of peak sunlight), 36kWh per month, and 432kWh per year. 

The above values are based on DC power output, to calculate what you can actually run on 300 watt solar panel you’d need AC power, which I’ll cover in a bit. 

The 80% average output from a solar panel during peak sun hours is based on the 30 days of power output from my 200-watt solar panel. 

I have a 400-watt portable solar system with 200-watt solar panels connected together. That gives me about 1.9kWh of energy output per day with 6 hours of peak sunlight

You might be wondering what are these peak sun hours. well, i’ll explain in a bit

300-watt Solar Panel How Many Amps and volts?

12v 300-watt solar panel under ideal conditions will produce an optimum operating voltage (Vmp) 18.5v and optimum operating current (Imp) 16.2 amps. And a 24v 300-watt solar panel will produce an optimum operating voltage (Vmp) 32.2 volts and optimum operating current (Imp) 9.32 amps. 

That is why we need a charge controller, which will regulate the voltage output of the solar panel to safely charge a 12 or 24-volt battery. 

Related Post: Solar Panel Amps Calculator (Watts to Amps)

What Size Charge Controller with 300-watt Solar Panel To Charge a Battery?

To charge a 12v battery with a 300-watt solar panel you’d need a 12v 30A charge controller (Type MPPT is recommended), and to charge a 24v battery with a 300-watt solar panel you’d need a 24v 20A MPPT charge controller.

You might be wondering what are these peak sun hours. well, let me explain

Peak Sun Hours

Before explaining peak sun hours, first of all, let’s have a look at how solar panels are rated for their wattage.

Solar panels are tested under standard test conditions – STC. which includes 1000 watts per meter square of sunlight intensity (1kW/m2). 25oC solar cell temperature, and no winds. 

  • Peak sun hour = 1kW/meter2 of sunlight intensity 

This is why we consider peak sun hours when calculating the output of solar panels. 

The intensity of the sunlight will be different throughout the day. For example 

  • 0.2 peak sun hour (early morning) = 200 watt/meter2 of sunlight intensity 
  • 0.5 peak sun hour (before noon) = 500 watt/meter2 of sunlight intensity 
  • 1 peak sun hour (noon) = 1000 watt/meter2 of sunlight intensity 
  • 0.8 peak sun hour (Afternoon) = 800 watt/meter2 of sunlight intensity
  • 0.4 peak sun hour (evening) = 400 watt/meter2 of sunlight intensity 
  • 0.2 peak sun hour (late evening) = 200 watt/meter2 of sunlight intensity 

How To Calculate Peak Sun Hours

To calculate the total number of peak sun hours your location receives use this PV solar calculator.

Step 1: 

Enter your complete address or just the city name 

How to calculate peak sun hours

Step 2:

Click on the result option. 

How to calculate peak sun hours
How many peak sun hours in florida?

Now you’d be able to see the number of total solar radiations your location receives month by month. 

In Florida city on average, we receive about 5.8 hours of peak sunlight annually. 

Instructions!

  1. Put the average annual peak sun hours in the calculator ‘peak sun hours’ box to find out the annual energy output from your solar panel. 
  2. To calculate the monthly output from your 300-watt solar panel, put the value of that month’s peak sun hours.

300 watt Solar Panel Output State by State – Chart

Here’s a chart about 300-watt solar panels’ total energy output in the US state by state. 

StateAverage Per day output from 300-watt solar panelAverage Per Month output from 300-watt solar panelAverage Per year output from 300-watt solar panel
Alabama1.2 kWh38 kWh457 kWh
Alaska0.7 kWh23 kWh285 kWh
Arizona1.4 kWh44 kWh535 kWh
Arkansas1.2 kWh36 kWh440 kWh
California1.3 kWh41 kWh501 kWh
Colorado1.4 kWh42 kWh509 kWh
Connecticut1.1 kWh33 kWh406 kWh
Delaware1.1 kWh35 kWh423 kWh
Florida1.3 kWh40 kWh483 kWh
Georgia1.2 kWh38 kWh457 kWh
Hawaii1.2 kWh36 kWh432 kWh
Idaho1.2 kWh36 kWh440 kWh
illinois1.5 kWh46 kWh561 kWh
Indiana1.1 kWh33 kWh406 kWh
Iowa1.1 kWh34 kWh414 kWh
Kansa1.0 kWh32 kWh388 kWh
Kentucky1.1 kWh34 kWh414 kWh
Louisiana1.2 kWh38 kWh466 kWh
Maine1.0 kWh31 kWh380 kWh
Maryland1.1 kWh35 kWh423 kWh
Massachusetts1.0 kWh30 kWh371 kWh
Michigan1.0 kWh30 kWh362 kWh
Minnesota1.0 kWh32 kWh388 kWh
Mississippi1.2 kWh38 kWh457 kWh
Missouri1.1 kWh35 kWh423 kWh
Montana1.0 kWh31 kWh380 kWh
Nebraska1.2 kWh38 kWh457 kWh
Nevada1.3 kWh41 kWh492 kWh
New Hampshire1.1 kWh33 kWh406 kWh
New Jersey1.1 kWh33 kWh406 kWh
New Mexico1.5 kWh46 kWh552 kWh
New York1.0 kWh32 kWh388 kWh
North Carolina1.2 kWh37 kWh449 kWh
North Dakota1.0 kWh32 kWh388 kWh
Ohio1.0 kWh32 kWh388 kWh
Oklahoma1.2 kWh38 kWh466 kWh
Oregan1.0 kWh31 kWh380 kWh
Pennsylvania1.1 kWh33 kWh406 kWh
Rhode Island1.1 kWh33 kWh406 kWh
South Carolina1.2 kWh38 kWh457 kWh
South Dakota1.2 kWh36 kWh432 kWh
Tennessee1.1 kWh35 kWh423 kWh
Texas1.3 kWh41 kWh492 kWh
Utah1.2 kWh38 kWh466 kWh
Vermont1.0 kWh30 kWh371 kWh
Virginia1.2 kWh36 kWh432 kWh
Washington1.1 kWh34 kWh414 kWh
West Virginia1.0 kWh32 kWh388 kWh
Wisconsin1.0 kWh32 kWh388 kWh
Wyoming1.2 kWh38 kWh466 kWh
Table: 300 watt Solar Panel Output

Note: 1kWh = 1000 watts

The above chart is based on the average (annual) total number of peak sun hours. 

DC To AC Power Conversion loss 

As we have discussed how much DC power you can receive from your 300-watt solar panel but, to run most of the household appliances you’d need AC power. 

Watch this video to understand how DC and AC electricity output works.

To convert DC into AC we use an inverter, and most of the inverters are about 90% efficient. So there will be a 10% power loss when converting DC into AC

For Example

Here in Florida, I would receive about 1.4kWh of DC power output from a 300-watt solar panel in July. 

300 * 0.8 = 240 watt
240 * 6 = 1440Wh or 1.44kWh (1kw = 1000 watt)

Now let’s convert the DC into AC while using a 90% efficient inverter.

1440 * 0.9 = 1296 or 1.3kWh 

You can expect 1.3kWh AC electricity output from a 300-watt solar panel per day, considering 6 hours of peak sunlight.

Related Post: Solar DC Watts To AC Watts Calculator & Formula

What Can a 300-watt Solar Panel Run? 

A 300-watt solar panel can directly run a constant load of 240 DC or 210 AC. That means you can run a medium size new technology kitchen fridge, TV, Fan, Computer/laptop, LED light, etc… But with the help of a battery, you can run a 1300 watts of AC load for an hour with a 300-watt solar panel.

If you’d follow these 2 rules, you can run any appliance with a 300-watt solar panel 

Rule #1 

If your battery has reached its depth of discharge limit or doesn’t have any power, Then your load output AC load should not exceed the output of your solar panel’s AC watts. 

Rule #2 

If you have stored the power produced by your solar panel in batteries, Do not discharge your batteries at a higher rate. 

This you’d damage your battery cells, As a result, it will decrease the battery lifespan. 

Make sure to check your battery’s specs sheet and look for maximum discharge rate or C-ratings 

Can A 300 Watt Solar Panel Run a Refrigerator

A 300-watt solar panel can produce enough energy to run a large size kitchen (15 – 22 cu. ft.) between 10-20 hours.

I have discussed this topic in detail, click here to read for more in-depth information 

300-watt Solar Panel: FAQs

How many batteries do i need for a 300-watt solar panel

For a 300-watt solar panel, a 12v 150Ah lithium (LiFePO4) battery or a 300Ah lead-acid battery would be the best suit.

To calculate the size of a battery bank i would suggest you to consider the highest number of peak sun hours and multiply the number of peak sun hours by the rated wattage of your solar panel 

For example

If i would have a 300-watt solar, my calculations would have been… 

6 peak sun hours (July, which is the highest number) 

6 * 300 = 1800Wh or 1.8kWh

For a 12v battery divide the calculated value by 12, and 24 for a 24v battery system 

1800/12 = 150Ah 

A 300-watt solar panel will produce about 150 amp-hours of power output per day under ideal conditions. Considering 6 hours of peak sunlight. 

Lead-acid, AGM, and gel batteries have a depth of discharge limit (DoD) of 50%. Which means you can only draw them 50%. 

But the lithium-ion (LiFePO4) battery type is the only one that can be fully drained 

What size inverter for a 300-watt solar panel

The size inverter will depend on your wattage consumption or how many watts of appliances you’d like to run 

For Example

After calculating, your total energy consumption is 500 AC watts 

500 * 1.2 = 600 watts 

You’d need a 600-watt inverter to run 500 AC watts. 

How Many 300-watt Solar Panels To Run a House

According to the U.S information administration (EIA), the average electricity consumption of US residential customers is about 893 kWh per month. So you’d need about 20x 300-watt solar panels to run an average house in the US fully on solar power.

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I'm an experienced Sales Consultant with a demonstrated history of working in the renewables and environment industry. Skilled in Photography, Customer Service, and Sales.