All You Need To Know About 300 Watt Solar Panels

A 300-watt solar panel is amongst the bigger solar panels you can buy. But their size allows them to produce enough power to sustain most of your RV and camping electricity requirements easily.

If you want to decide whether a 300-watt solar panel is right for you, there are certain things that you need to understand

Let’s start with a few basics.

  • A 300-watt solar panel will not give you 300 watts. The power rating tells you about the maximum power it can produce when everything is perfect. However, perfect conditions rarely exist.
  • A solar panel will suffer from multiple losses like transmission loss, conversion loss, storage loss etc., and these losses lower the actual power output you are going to receive
  • Different places receive different amounts of solar radiation, so you get different output based on your location.
  • A battery kit is essential if you want to take full advantage of your power system.

Solar Panel Power Outputs

With improvements in technology, companies can now produce 400-watt solar panels. Therefore bigger brands like LG, Panasonic etc., are shifting away from the 300-watt solar panels.

Still, 300-watt solar panels remain popular in domestic use.

Size and weight of a 300watt solar panel

The size of a 300-watt solar panel is around 64.5 x 39 x 1.6 inches or 164 x 99.2 x 4 centimetres which makes it over 5 feet in length and a little more than 3 feet in width. You can expect slight size variations with different brands.

A 300-watt solar panel weighs around 42lbs 0r 19Kgs.

300 Watt Solar Panel Price

A 300-watt solar panel costs around $300 to $350 without a kit, and with a battery kit, you can get it for $580

How much power does a 300W solar panel produce?

You will have to understand the actual power that you can get out of your 300-watt solar panel for practical purposes.

There is a simple formula to calculate it.

E = A * r * H * PR

E = Energy (Kwh)

A = Area of your solar panel (m2)

r=solar panel yield or efficiency (15%)

H= Average annual solar radiation on tilted panels

PR= Performance ratio (Average Value = 0.75)

The real power that you will get out of your solar panels will vary by your location. To make it simple for you, we have calculated the average daily output of a 300-watt solar panel by state. However, it is important to understand that these are just average values; the true output can vary considerably even in the same state.

Code State/Province Average Annual Solar resource in kWh/m2/day Average Daily Solar Power in Watts
AL Alabama 5 955
AK Alaska 3.5* 669
AZ Arizona 7.1 1356.1
AR Arkansas 4.45 849.95
CA California 7.2 1375.2
CO Colorado 6.2 1184.2
CT Connecticut 4.5 859.5
DE Delaware 4.7 897.7
DC District of Columbia 4.7 897.7
FL Florida 5.3 1012.3
GA Georgia 5 955
HI Hawaii 6.5 1241.5
ID Idaho 4.7 897.7
IL Illinois 4.6 878.6
IN Indiana 4.3 821.3
IA Iowa 4.7 897.7
KS Kansas 5.7 1088.7
KY Kentucky 4.45 849.95
LA Louisiana 5.2 993.2
ME Maine 4.3 821.3
MD Maryland 4.55 869.05
MA Massachusetts 4.5 859.5
MI Michigan 4.25 811.75
MN Minnesota 4.7 897.7
MS Mississippi 5.2 993.2
MO Missouri 4.8 916.8
MT Montana 4.6 878.6
NE Nebraska 5.4 1031.4
NV Nevada 6.4 1222.4
NH New Hampshire 4.4 840.4
NJ New Jersey 4.5 859.5
NM New Mexico 7 1337
NY New York 3.9 744.9
NC North Carolina 5 955
ND North Dakota 4.9 935.9
OH Ohio 4.2 802.2
OK Oklahoma 5.9 1126.9
OR Oregon 5.4 1031.4
PA Pennsylvania 4 764
RI Rhode Island 4.7 897.7
SC South Carolina 5.2 993.2
SD South Dakota 5.2 993.2
TN Tennessee 4.7 897.7
TX Texas 6 1146
UT Utah 6.2 1184.2
VT Vermont 3.9 744.9
VA Virginia 4.7 897.7
WA Washington 4.5 859.5
WV West Virginia 4.2 802.2
WI Wisconsin 4.4 840.4
WY Wyoming 5.6 1069.6


What can a 300-watt solar panel run?

As you can see, the average daily power output of a 300-watt solar panel ranges from around 669 Wh/day to over 1375 Wh/day in the united states. If we average out all the values in the table, we have 955 Wh/day.

You have to understand that 300 watt is the instantaneous power rating. The average daily power that we have calculated is known as accumulated power.

So in practical conditions, what you can run on your solar panels will depend on accumulated power rather than instantaneous power.

Device Power Run time (If You Used Only One Device)
60 Watt Bulb 60W 16 Hours
LED 6W 159 Hours
Cell Phone  5W 191 Hours
Laptop 42W 22 Hours
Fridge 80W 12 Hours
DC Fridge  170W 5.6 Hours
Heater  1000W 57 Minutes
Booster Pump 60W 16 Hours
Blender 500W 1.91 hours

Can a 300-watt solar panel run a refrigerator?

Yes, a 300-watt solar panel can run a small fridge (80 watts) or a DC Fridge (170 watts). However, you will need a battery to accomplish that; and you can expect an average runtime of about 12 hours for an 80W fridge and 5.6 hours for a DC fridge in a day.

Please note that these values will vary considerably based on your location, weather conditions and usage.

Can a 300-watt solar panel run an air conditioner?

A 300-watt solar panel can only power an air-conditioner for a few minutes. The smaller air conditioners used in RV have a power rating of 1000Watts to 1500watts. With a daily charge of 955 Wh/day, you can barely run an air conditioner for 38 minutes to 57 minutes which may not be the best use for your solar panels.

Final Thoughts

A 300-watt solar panel is a great option for off-grid power. It has gained well-deserved popularity amongst RV owners. For most users, this panel adequately fulfils their basic power requirements.

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