Battery Charger and Selector Switch Position

[theArchitect]

If I'm plugged into shore power and my charger is turned on, does it make any difference what position the battery selector is set on - 1,2,both,off? Thank you!

[PBzeer]

Depends on how you have the charger wired to the batteries. If it goes through the switch before the batteries, then yes, it matters. If it doesn't, then the switch is irrelevant.

Currently at 25 46 43 N 80 11 08 W

[stevemac00]

Battery chargers need to see a load so it's almost a certainty they're wired directly to the batteries and thus independent of the switch.

You should look for a smaller gauge wire attached to the battery and trace that back to your charger.

You didn't ask but the same isn't true for the alternator charger. Usually that's the same heavy gauge wire that goes to the starter from the common output on the battery switch. So when you're under engine power, be sure to switch to both/all batteries.

[theArchitect]

Thanks for the feedback! If the switch should be set to both batteries while underpower, It should be set to both batteries when I start the engine since I should not change the switch setting while the engine is running, correct?

[Cruisingdad]

COrrect. DO not move the switch when running (well, I think you can go from 1-2-both as long as you do not go to off... but better not try that at home. Best rule of thumb is just not to do it.

Truth is that there is no reason not to keep that thing at ALL/Both. Always keep your batts parallel. Period. If you do not have a seperate engine batt, get one and take the time to put it in - or get to be good freinds with Sea Tow.

- CD

[CapnHand]

It was covered here: Battery Selector Switch - proper use