Mostly a myth but if you Supercharge cold locally, without pre-heating the battery, it could conceivably cause the Battery Management System (BMS) to allow more power than ideal (at that battery temperature) for expediency's sake. Even in this case it wouldn't be enough to ruin a proper battery, so it looks like your battery had a manufacturing defect to begin with and that caused the short life.Has anybody heard not using a slow charger and using a fast charger all the time damages battery??