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How Big Can I Go?

Frolf Lundgren

Joined: Feb 20, 2012
Posts: 39
Location: Finland, MN
I have three 20-watt solar panels (Sunforce). The box claims to produce 2,940 watts (196 amps) per week (60 watts x 7 hours x 7 days). So this assumes one gets seven hours of optimal light. I would like to use this to power a chest freezer. I am just curious if A) this will power a chest freezer and B) how big can I go?

I was using this page as a guide to shop for freezers based on power usage

Chest Freezer
<16 cu ft
No Icemaker
All Brands

Will these three panels power up a chest freezer that needs nearly 200 KWH/Year?

I assume that I am producing 164.64 KWH/Year (2940 x 56), which means no or find a chest freezer the size of your chest. Someone tell me my math is incorrect, please. I did purchase two sets of these panels as the hope was one for the freezer, the other for the wofati. I guess I'll have to combine the two sets into one somehow.

My uncle always said, "Raising beds is better than wetting them".
Kevin Pegg

Joined: Apr 02, 2012
Posts: 9
Location: Smithers, BC Canada
A generic answer is "not even close" but the devil is in the details. It's very risky relying on marketing claims on very cheap low quality panels to keep your valuable food frozen.

I can help you with this, but the first consideration is where do you live, how are the solar panels mounted, and do they get unobstructed sunshine?

A word of advise, these cheap panel kits like this purchased from retail outlets are actually significantly more expensive than getting quality panels from your local solar geeks.

Basically, we need to determine, in kWh how much energy the freezer uses, then looking at the climate normals in your area, then can do the math and figure out how much solar input to meet that need.

Frolf Lundgren

Joined: Feb 20, 2012
Posts: 39
Location: Finland, MN
thanks for the kick in the butt Kevin.
Luke Townsley

Joined: Apr 17, 2010
Posts: 130
Location: Dugger, IN Zone 6a
You also have to factor in battery storage and inverter conversion losses.
subject: How Big Can I Go?