After almost six years I am concerned that the battery is nearing the end of its life. So, I have been looking for non Volvo replacements. I live in California and have found group 48 batteries with vents at Les Schwab and Kragen. I know that Schwab is a western states only operation but maybe Kragen is nation wide. The price at both stores was about $80.
My usual strategy is to wait for the battery to exhibit signs of failure and then charge once and if the signs persist and the battery is more than three or four years old replace it. My wife disagrees and wants to replace them at about five years to avoid the failure. I am too cheap to do that. I can only hope the battery fails me and not her.
South Lake Tahoe, CA