Yes, this is first time since 2007 that this has happened. Batteries have been changed once in that time.........but the cranking battery is different than the other two. The other two are Optima Blues in series. It is possible the cranking battery is like me, old and decrepit and tired. I'll check that out. I sure don't want to kill the Depthfinders and then turn back on every time........that's 11 feet of walking for one thing. And then they'd reset........ugh. But I'm learning more about all this than I knew.............thanks!