Diodes and battery charging

[LeonF]

Simple question...I have a 1 2 selector switch and a simple diode system. There is no voltage drop at the batts so assume the supply had been uprated. I always start on 1, run for a while and then switch to 2 as I have done on previous boats. Is this neccessary with the diodes or am I not allowing the system to function as efficiently by doing this?? Should I leave the switch on both when motoring to get the best charge I can ??

 

[ccscott49]

Without a wiring diagram, it's a wee bitty difficlult to advise you.

 

[CSFenwick]

As already said without a wiring diagram any advice may be well wide of the mark! If you have a diode in the system then I'd expect the aternator to be connected on the battery side of the switch. If you trace the + wire from the alternator it'll go to the diode (perhaps via a booster first?). Coming off the diode there will be wires that go back to the batteries. Is the 1-2-both selector switch between the diode and the batteries - or is the diode on the battery side of the switch? If the latter then the switch has no function with regard to charging from the alternator. You're always charging both batteries even if the switch is in the 'off' position.

 

[Salty John]

Because you have diodes to isolate the batteries from each other you may as well start on both and run on both. This is more convenient than having to decide which battery to charge first, and when to switch to the other. When you switch the engine off you need to select the battery you want to use for house duty, saving the other for engine starting. This way you will always have a charged battery even if you flatten the house battery.

 

[KREW2]

Hi
When it's switched to both, can we assume its charging both batteries?
Keith