Freep wrote:
I just got off the phone with Lifeline. They said it's normal for that noise to happen when you discharge deeply and then start charging again.
Hmmm .... that is a STRANGE THING for a battery to "normally" do!!
I would have guessed that it was the automatic pressure relief valve opening up on one or the other of your AGM Lifeline batteries due to vapor build-up inside one of the batteries because it was being charged too quickly.
I've never had this happen on my (other brand) of AGM RV batteries, but I wouldn't be surprised if there was some kind of "noise" connected with the opening up of the vapor pressure venting valves that all AGM batteries have.
