It's time for some new batteries for the trolling motor and I can't decide on which ones to get. Considering some Duracell AGM's from Sam's club but have a few issues to consider. For one they don't make one that will fit my trays exactly. I would like to get the biggest ones I can - the 31 series I think are the biggest - but they are slightly larger than my trays. Second I have an old charger that came with the boat, so I am wondering how effectively it would charge an AGM battery or would I need to upgrade my charger as well? I bought an Optima for the cranking battery 2 years ago and it has worked great. Would buy some for the trolling motors if I could find a deal on them. Sam's no longer carries them because they supposedly moved the manufacturing to Mexico. Don't want to spend to much cause I am going to get another boat in a year or so. Reviews for this battery were mixed???