I have battery testers, electrical meters, single and dual phase meters, multi-meters, battery chargers, battery maintainer., tools, battery carrier and emergency battery starter. ALL of which did no good in telling me why my starter battery was dead every dad gum spring for the last 4 years. I use ProTroll trolling and starting batteries. Very good batteries with great warranty. Each Spring the trolling batteries would be at 3/4 full and the starting battery dead as a dinosaur. A 3 bank charger for the trolling batteries and a single bank for the starting battery. Late in the Fall, I use a portable charger to top the batteries and check them. My final chore is to put a 2 amp maintainer on the starting battery. All should be good for Spring even if I don't fish that winter.
I have 3 computers on my Puma. One for the Optimax and 2 for the stereo. I have a big stereo with lots of speakers and stereo controls on the console and very front of the boat. I like my tunes and a disc of the band "Alabama" is playing loud as I run the lake. The battery maintainer handles the electrical load used by the computers.
My oldest friend is Mayor of Lake Ozark, my old fishing partner and a darn good electrician. We started checking for shorts and leaks in primary lines and switches. By the time we finished the third tier of circuits, my buddy says, " there is nothing wrong with your boat". I could tell he was irritated so we went to the condo for some brew. Middle of his 4th Michelob, he says he is going to check the batteries every week until he finds an answer or winter is over. He calls this morning and says the power is off to my boat slip. Only my slip as the rest of the dock has power. We have both security guards and permanent maintenance employees. The security is supposed to walk and check the docks twice a shift, especially after storms. Bingo! Someone hasn't been doing their job. Seems everything is checked during boating season but once the season's over...
I talked to our Marina manager about the problem. He will check my slip for power after every storm and reset the breaker if needed. After four years, three starting batteries, two days of testing, a lot of cursing and the problem is solved mostly by luck.