So my cranking battery has been drained dead 2x now. Brand new battery too. It’s never had a draw before so just out of blue last two times. I have a kill switch for my 3 graphs, the master switch in dash kills live well, bilge etc. only other hook ups are kicker motor and 3 bank charger. I put boat away…dont use for 3 weeks (been wader fishing), plug in charger over night here and there. Then take out this morning and deep cycles good, crank …stone dead. Cannot find draw and has never had one. In researching, I think it’s a bad 3 bank charger?? I read a diode can go bad and reverse draw when not charging?? I’m going to put a new kill switch (big boy) on the main motor cable to kill whole boat but in the mean time….do you wiring/electrical/battery guys think I’m on to something??