Make sure that the battery charger you're using is good for the type of battery it is such as AGM, lithium, or standard lead acid. Using the wrong one can shorten a battery's life.
Well now that we have your attention, shouldn't you be removing that link in the OP's post or....is it harmless just sitting there?
..as for making use of a thread started wrongly.........about Battery tenders...after having a battery go bad even though it was on a BT Jr. with a green light on, I don't use those
any more, I've decided to use only the larger anti sulfating ones from OptiMate and Xtreme.