Voltage at panel

[wired1236]

I was installing the perfect pass the other day and noticed that I have about a 0.6V drop measured between the battery and the ingition switch. The v-drop goes ever further down when they key is turned on to about a 0.9v drop. I expect a little drop with the key on but not a 0.6v with nothing but the accesory swith on which is ONLY connected to the perfect pass, (I moved the stereo off the ignition switch). The batteries are within 6' of the ignition switch with the factory 4awg wire. I looked at all the connections I could see to make sure they are good and tight so is this normal? Normally I would think a lose ground or something else to create a high impedence.

[chpthril]

Does your Tige have the factory EIDB Dual Battery System? If so, those batteries are isolated through a diode type ISO. This diode can account for up to a .7V drop between the alternator and the battery. Depending on use, its also possible to have the house and main batteries no charged to the same rate.

What is the voltage on each battery?

Are you saying that the system voltage drop .3 when the key is on ACC, or there is a .3 voltage drop across the switch? There is a difference and diagnosing will go in 2 different directions. A voltage drop across the switch would be a bad switch, and would not be caused by the load, but a drop in voltage when in the ACC or ON position will be dependent upon the load.

IIRC, the ignition switch is fed with by the main battery, but the helm BUSS was fed by the house battery.

[wired1236]

Not sure if it's factory or not but I believe it has a diode on it so that could explain the drop. It does have the battery switch. The battery voltage of each battery shows 12.9 (after a fresh trickle charge) with no load or engine on. I checked before and after the ign switch, hot side is ~12.3 with the key off, 12.0-11.9 with the key on both sides. My accories & stereo are fed by battery 2 and the engine, ignition and gauges off of which every battery the selector is switched to.

I may just be worried about nothing...but figured I would ask. I know getting below 12v means there's just not much headroom after a day of running battery 2 so I may find myself using my battery selector more than I figured. I am new to the boat so I'll give her a shot this summer and see if I need to go any further with this.