I gave observed that cars with powered charging ports do not have vents in the wheel arch in order to protect the opening mechanism. Therefore any suggestion that blocking the vent will have a detrimental effect is simply untrue.
My friend who is a battery "nerd" advises never charge the battery to 100% if you are not going to use the car for a couple of days. He says that you should not store the car with more than 85% charge to prolong battery efficiency.