How weather affects solar charge speed
Clouds, temperature and panel angle change charge time. Learn rules of thumb you can apply anywhere.
Quick take
Clouds and heat reduce output; a good rule is 70–80% of rated watts from panels in clear sun.
How to use the calculator
- Open the calculator linked below.
- Enter the numbers that match your setup.
- Use our rules of thumb to sanity-check the result.
Rules of thumb
- Solar gives ~70–80% of nameplate in good sun.
- Cold panels are slightly more efficient than hot panels.
- Use MPPT and keep panels angled toward the sun.