catalina27-talk: Battery / Electrical Problem

[mcewenjv]

   As Ralph says, advice is worth what you pay for it, but if your lights and instruments seem to work when you are in both battery one and two/both, then what may happen is a bad battery cable crimp or connector, or a switch problem.  When you pull a lot of juice (technical term) to start the motor, a bad connection will cause a big voltage drop across it, leaving less voltage (and current) for the starter.  Everything seems to work ok when you use lights or instruments, because they only use a little current compared to the starting motor, and cause a little voltage drop.  This bad connection can be in either the positive leg, going to the switch from battery 2, or the negative leg, connecting battery two to the buss (or more likely to battery 1, negative).  But, since it also happens when you are in "both" position, right now it sounds like the switch.  This is assuming that the wiring is correct for what you are trying to do. (meaning it used to work fine on either one/two or both, but doesn't now.)
  An easy test is to put the switch in off and use a car jumper cable across the switch, and see if that cures the problem.

Jim,  Whiskey Girl
Dana Point, CA