First off, not having a full understanding of the many details of a fairly new technology does not make you dumb. Just keep learning. You can run your car at any level of charge down to zero and DC fast charging isn’t necessarily bad for it.
What is bad is heat and plating. If you are interested I can find a great video on lithium batteries but basically the lithium passes through between the cathode and anode to join the electrons that power the car. Less lithium means less available charge. You lose available lithium a couple ways but mostly from heat causing the lithium to plate the anode. If the battery has proper management, and part of that is cooling built in as well as only charging to 80%, it should not plate as much and therefore should not degrade faster than normal.
Unlike a cell phone battery an EV battery is many cells and the management system decides which cell to send a charge to instead of just charging everything at once. If it can distribute charge evenly without taxing one cell it can keep that charge safe. Over 80% there are less options to distribute so the likely hood of damage is greater. You can still charge to 100% but it is safer to do it at a lower charge rate and less often.
What is bad is heat and plating. If you are interested I can find a great video on lithium batteries but basically the lithium passes through between the cathode and anode to join the electrons that power the car. Less lithium means less available charge. You lose available lithium a couple ways but mostly from heat causing the lithium to plate the anode. If the battery has proper management, and part of that is cooling built in as well as only charging to 80%, it should not plate as much and therefore should not degrade faster than normal.
Unlike a cell phone battery an EV battery is many cells and the management system decides which cell to send a charge to instead of just charging everything at once. If it can distribute charge evenly without taxing one cell it can keep that charge safe. Over 80% there are less options to distribute so the likely hood of damage is greater. You can still charge to 100% but it is safer to do it at a lower charge rate and less often.
