Where to terminate white wire

[Noah2003]

3EBE5DEC-2B1E-4DDF-B4E7-80DFE243025E.jpegHi all, new member here. Have just wired up a new battery switch but unsure where’d you terminate the white wire for ECU. Before I had a 1 2 combine switch and just put it on the output. The new switch is a dual circuit switch and therefore has 4 terminals; engine input (alternator), start battery, house loads, house battery. Some people say put it directly on the engine bat positive, but this would mean it’s always live even when the battery switch is in the off position. The only other place I can think to put it is the alternator stud on the battery switch, as this is not live until the switch is turned to on, however I am told this could also expose the ECU to voltage spikes. Any ideas greatly appreciated! Cheers

[tsturm]

mine is directly to the + post on the starting battery & has been for 2129 hrs. & 8 yrs. no draw when the ign. s/w is off

[Noah2003]

Many thanks, but that means that the key will always work in the ignition and the dials will light up but the engine obviously won’t crank when the switch is in the off position. Is there a way round this?

[Murray]

My instrument cluster lights are wired to the navigation lights switch. You want your white wire to be hot all the time otherwise you would have to climb in the boat to turn on the ignition key to operate the tilt/trim.

[Noah2003]

But surely I want all my electrics off when I’m not in the boat? So surely I’d want it on a battery switch so I can isolate it when not in use?

[Harper]

I have the same setup as yours. Put the white wire on what I think you're referring to as the "engine input," assuming that is the stud where the heavy cable to the start motor is attached. With the battery switch "ON," that would be the same as having the white wire attached to the positive teminal of the start battery.

I'm not real sure why you refer to that stud on the battery switch as "alternator." My charging system is separate from the battery switch circuit. Both batteries are charged viw a dual battery isolator lead from the motor driectly to the batteries.

[tsturm]

But surely I want all my electrics off when I’m not in the boat? So surely I’d want it on a battery switch so I can isolate it when not in use?

Turn ign s/w off all instruments are without power, turn batt s/w off everything else is without power