Listees, When building my boat I had Arild draw up the electrical schematic for the builder to follow. Upon arrival in the US I had Arild inspect the installation to see if it were up to his design specifications. One of those design specifications were to install two banks of batteries. Each battery is 2 volt with 12 in each bank. I commented to Arild that having 24 batteries for my house power was going to be an expensive proposition, let alone the effort to extract them, to replace and how long will they last. The AGM manufacturer quoted 10 years plus dependant on duty cycles. It was at this point Arild suggested the installation of a nano pulse mechanism. I installed a PulseTech on each battery bank and the main engine starting bank. You may call it insurance but I thought it was an expense I was willing to take. It is probably still too early to tell but my batteries are as responsive to charge as the day I left cruising, almost three years ago. I can say that with 1200 Ahrs of 24 volt batteries we have become very dependent on them. We are on a 53 trawler and to date have less than 350 hours on our generator. (this is in part because of the way Arild designed our system0). So then the question is, "If you may have to pay 5k-8k for a new set of batteries in 3-5 years or spend another $500 now to take a chance they may make it several more years, and have better efficiency during their present duty, would you spend the money?" Time will tell in our case if it was money well spend or just more boat bling. Les Dobbe "Voyager" Selene 53 St. Thomas USVI