What happens to charge controller when maximum voltage exceeded?

[Dzl]

Okay thanks

Today I am the fool. Thanks for setting me on the right path, It never occurred to me that a panel makes higher than it's rated voltage when the temp is less than 25c

Here is a table for conservatively estimating temperature correction, this is from the (US) National Electric code:

The other method is to do the math based on your panel specs (or use a calculator like this one)

 

[fafrd]

I'm not picking up what you're putting down.

Your VOC will be at it's highest in full sun. Your MPPT will be happy so long as your stay within the manufacturers specifications.

It’s current that goes up with increasing sunlight - Voc doesn’t really change with increasing sunlight except for the increase in temperature that typically accompanies sunlight getting stronger).

Voc (as well as Vmppt) decreases with increasing temperature and increases with decreasing temperature (all with current of 0A).

Isc (as well as Imppt) increases with increasing temperature and decreases with decreasing temperature.

With increasing temperature, the % decrease in Vmppt is greater than the % increase in Imppt, which is why panel efficiency is lower in summer than over winter...