Well,never thought I would totally depend on battery back ups! I have a generator and the house is wired for it!got it covered! Battery's would give me time to get home and start the generator ,right! What happens if it doesn't start,didn't think of that one,tell this week. We lost power for over 18 hours. The battery's worked flawlessly and kept everything alive,thank god! I never did get the generator started,need to rebuild the carberator and the kit takes 5 to 7 days to come in. These back ups saved thousands of dollars in coral and seventeen fish. They we're fully recharged in about 24 hours and ready to go for the next time. Money well spent! I recommend anyone who has vortech's to spend the extra money and get a ton of piece of mind !