Solar array
How many watts of solar does your roof need?
Your daily use divided by the sun you'll actually get. Then we turn that number into boxes you can buy.
Formula from the original megawattrv.com calculator
Minimum array
0W
- Array needed at each sun-hour level
- Your pick
How the math works
Minimum array watts equal daily watt-hours divided by sun hours times 0.75. The 0.75 covers heat, dirt, wiring, and charge losses, and it's the same figure the original Megawatt calculator used.
A 4,200 Wh day at 4 sun hours needs 1,400 W. Drop to 3 winter hours and it jumps to 1,867 W. That curve on the chart is why people who chase the sun get away with smaller roofs.
The pack options round up to whole boxes of each size Megawatt links. Our pick mixes sizes to land as close to your number as possible.
Before you buy
Measure the roof. Air conditioners, vents, and the antenna eat the flat rectangle you're imagining. The solar planner lays panels around them for you.
Consult a certified electrician before you change your rig's electrical system. That note came with the original tool, and it still stands.