Pelagic, Thanks for the response. I know my Evinrude Etec G2’s are unique in todays outboard arena. I purchased my 2520xl less than two years ago and the engines have been exceptional.You will have no problems using AGMs. I’d be doubtful of lithiums, since I’m not yet convinced they’ve sorted out the issues they’ve had in the past. Same with gel cells, as they don’t like charging voltages over 14v. A standard outboard alternator will eventually roast them.
During my time with this boat I’ve been going thru all it’s systems. As I said I’m now reworking the whole battery system. Never used AGM’s before but they sound promising. I’m also impressed with the concept of BEP’s battery management concept. I’ve followed your and Warthog’s input and am looking forward to completing the project.