With charging it is probably worth looking at advice from Tesla who have the most knowledge and experience.
Electric Vehicles have two methods of charging.
First is AC using the Menkes Type 2 socket, (The upper bit) and this uses the car's own Battery Monitoring System (BMS). This is a very clever piece of kit as it monitors the battery including all the individual cells.
It will not allow you to overcharge the battery and can perform cell balancing if the car if left on charge, say over night.
This is worth doing once a month, more often if you continually Rapid (DC) charge because you are 'on the road' a lot.
Second is DC charging, using the lower half of that plug at the front.
The difference is that the BMS doesn't have full control of the charging, only 'telling' the DC charger how much current and at what voltage to deliver, otherwise it is a DC source almost straight to the battery.
It is generally agreed, though with newer battery technologies this is changing, that using Rapid DC charging (50Kw and above) charging to 80% is advisable.
There is nothing wrong with charging to 100% except the charge rate drops off drastically after 80% and takes far longer to charge, thus hogging a charger unnecessarily.
If no one is waiting and you are not in a hurry, the 100% is perfectly OK. The proviso that this isn't done all the time as the the cells will go out of balance and your range will be reduced until you balance the batteries using AC and the car's BMS.
Research has shown that the capacity of the battery falls initially, then recovers often to the same or sometimes higher than it was originally due to the battery chemicals stabilising!
TeslaBjorn aka Bjorn Nyland, on YouTube has some very interesting facts regarding EVs and their batteries and is widely regarded as a useful, accurate source of information.
Interesting to watch even if you find his delivery 'quirky'. A Thai in Norway!!
