There is no one hard number – the number of solar panels needed to run a fridge depends on several factors such as:
- the volume of space reserved for foods to be cooled (specified in liters or cubic feet)
- the average number of sunshine hours received at the location where the fridge is
- the fridge’s power consumption.
For instance, a larger fridge consumes more power and therefore needs more solar panels while a more efficient fridge needs fewer panels to run.
However, as a rough guide, a fridge with a capacity between 1.1 to 3.1 cu. ft. should be able to run with 2 x 100 W solar panels at a location receiving at least 4 sunshine hours.
How many solar panels needed to run a fridge (using its its annual kWh)
To calculate the number of panels needed to run a fridge for an annual energy consumption above, you can use the calculator below.
# 1. Calculating a fridge’s power consumption from its annual kWh rating
Manufacturers usually indicate the annual kWh rating of a fridge in the technical section of the manual of the fridge.
To arrive at the number of watts a fridge consumes, use the formula:
((Annual kWh of the fridge) ÷ 365) ÷12. This assumes a duty cycle of 50%, i.e. the fridge is on for approximately 12 hours per day.
# 2. How many amps does a fridge draw?
To work out the number of amps a fridge draws, use the formula:
Power consumption of fridge in watts ÷ voltage of power supply (volts)
The table below shows various fridge models, their capacities in cu.ft, annual energy consumption, daily energy used, and the number of solar panels needed to run the fridge.
Note: This assumes a 100W solar panel.
|No.||Fridge Model||Capacity (cu.ft)||*Annual kWh||Daily kWh||No. of Solar panels|
|4||Whynter CUF-110B Energy||1.1||215||0.589||2|
Annual kWh values are based on the technical specifications provided by the fridge manufacturer
# 3. Will a 100 watt solar panel run a refrigerator?
A 100W solar panel will likely not be enough to run a fridge. A 100W solar panel produces an estimated 146 kWh per year which is not enough for a portable fridge (160kwh).
200W would be ideal to run a portable fridge with 4-5 hours of sunshine comfortably.
# 4. What capacity of solar panel for 12V fridge?
The number and size of solar panels needed to run a 12V DC fridge depend on the size and power consumption of the fridge.
For instance, 1.7 cu. ft. (48l) portable fridge which is ideal for an RV or camper consumes about 65W ( about 5.2A at 12W).
1 x 200W solar panel will be able to run the fridge comfortably at a location that receives about 4-5 hours of sunshine.
# 5. What size of solar panel to run a 32 l or 40l Engel freezer?
Assuming a DC current draw for a 40l Engel freezer of 2.6 Amps and a duty cycle of 50%, quite likely lower, a minimum 120W solar panel but ideally 150W of solar for about 5 hours of sunshine works well.
This capacity will compensate for overcast skies and avoid the need to track the sun
across the sky.
This capacity of the battery can be used to charge an AGM battery of capacity 75-100Ah.
# 6. What size of solar panel to run a 80l Engel freezer?
For an 80l Engel freezer, 240-300W solar panel charging a 150-200Ah battery works well.
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