John Harry

I do the same, even if it load tests OK. The hassle of a dead battery isn't worth saving a couple of bucks.

gliot1

I think wording here is key. You want a float charger, as these are designed to not damage batteries as trickle chargers have been known to do. Along with using a float charger I have a time on mine and only float charge it about 2 hrs per day, as that is all that is needed. Beyond all of this I suspect as others have said, that your 6 yo battery is the issue, not the charger. Today most batteries seem to be fine one day and dead the next with shorted cells. I have seen it a number of times on club trips where we go in for lunch, all cars running fine, and someone will come out to a totally dead battery, not from leaving anything on, but from shorted cells.