No power to anything - dead in the water

[jhiestand]

The other day we were switching riders (engine off, but accy on) and when I turned the KEY to start (yes, we have an SE) I could've sworn I heard a loud click and all power in the boat died. Nothing to the dash, the starter wouldn't engage, nothing. Well NEARLY nothing. Turning the key back and forth from OFF to ON the engine water temp needle would tick ever so slightly, but that's all. Bilge pumps won't turn on, no blower, no ballast pumps, no anything. Both batteries are showing 12.45 when I check with a multimeter, and I've checked at the perko switch and get similar voltage.

My current thought is the 50amp breaker we have under the port lounge right by one of the batteries. It didn't trip, at least I can't push it in but when I measure voltage when grounded at the battery I get 3.5v to 4.5v on both poles. Is that right? With the battery switch off I get zero voltage (duh) and the fact I get the same reading on both poles seems to indicate it hasn't tripped. That seems low to me, and I guess maybe it could also be an issue I get a fluctuating reading. Any thoughts?

[jmo]

I would begin by looking for a loose connections and take the starter battery to an auto parts store to do a health check, reading 12 volts with a multimeter doesn’t tell you the whole story. I would also check behind on/off/bilge switch. My old 2001 had it mounted on the kicker panel at the drivers feet and one of the connectors to it on the back side had come off leaving me dead in the water. This happened because i forget to tighten the bolts on the kicker panel after putting a heater in - the movement jarred it loose.

[mpost]

Sounds like your problem is between the 50 amp breaker and the Battery. Is your switch between the battery and the breaker? With only 3-4 volts at the breaker you have some kind of high resistance connection or wire between the battery and the breaker.