Question about Shore power, and battery switch

[Cape Codder]

Here goes...(show's my ignorance)
If I plug into shore power, and turn on my main AC panel, I can charge my batteries with the battery charger.
But, my question is: Does it matter where I position the battery switch?
1, 2, or both, or OFF?
Thanks in advance for any help.

[DougSea]

Cape Codder,

Like many things on the Albin's: It depends...

If you have a device such as BlueSea's ACR (Automatic Charging Relay) then the switch position shouldn't matter. This, and other similar devices, route power to the starting and house bateries and are wired seperately from the switch.

See here: http://bluesea.com/category/2

If on the other hand your boat is set up like mine, with no ACR, then only the batteries which are "on" will be charged.

Not a great answer but that's how it goes...

[Denis]

Bob, my boat is wired the same as Doug's. It will only charge to the battery that is selected on the battery switch. Denis

[mhanna]

Hmmm I will have to look at mine today. I have a dual bank Charles charger and thought I was sure it would charge both battery's regardless of the switch position. Therefore at the dock I leave it on (2) (because 1 has the pumps hard wired)... If the shore power goes away and the refrige runs down batt 1, i still have a batt to run the pumps.
I will check and reply....

Matt

[Tuxedo]

My boat (1998 31TE) has the charger wired directly to the batteries, so the switch positions do not matter. Look at your batteries and see if there is an extra little wire running to them. If so, it's probably the charger.

[DougSea]

I probably should have added that my boat has the West Marine combined charger/inverter. So it's wired differently than a boat which has both a charger and separate or no inverter. I can say for certain that my house battery has NO connections other than the big main cables. I'll have to double check my 2 start batteries.

Regardless of how my boat's wired now I have plans to rework the entire battery setup to better isolate the house and starting batteries and to make sure, via an ACR or similar, that my start and pump batteries are always charged first.

[tomcat rio]

put a meter across the batttery terminals and check the voltage with the charger on and off. if the battery is being charged, the voltage should be slightly higher than when the charger is off.
do the check under several conditions:

battery switch in all positions.

d c main on and off.

a c c/b on and off.

record the results.
...
one thing to remember about shore power. sometimes it fails. if your battery switch is not in the off position, any load (like the reefer) will quickly drain the battery and your bilge pumps will not be on line.

[Mariner]

Our boat is different, but on ours, the dual bank battery charger will charge both batteries, regardless of switch position. It's actually better to have them isolated, so both batteries are actually being charged, rather than simply reading the voltage coming off the other side of the charger.