More battery management questions

Spyderweb

My new to me 2008 330 EC has me confused regarding the battery switches.  I'm used to a single engine, 2 battery setup with the "1", "2", Both", and "Off" MBSS.  I typically start engine on "1", and switch to "2" during the day (and sometimes evening) to run all the 12 volt stuff (rarely used fridge).  When I'm away from the boat I have power and leave the charger on.  We're typically out on the boat 30-40 days a summer.  I got 9 years out of the original batteries managing them this way.

The 330 has 3 batteries in a row in the port corner in engine room, with what I believe to be 2 batteries, 1 each per engine, and a 3rd (furthest aft) serving as the house battery.  In the starboard corner just behind the generator is another battery, serving the generator.

The 1st photo above is an electrical panel in the cockpit. I think I understand the simple "On"/Off" switches for "House" and "Generator".  I would imagine you just leave them on all the time, except perhaps if you want to shut down the House battery because it's getting too low and you can't charge right then.  Just above the red switches are 3 rockers, for port and starboard engine batteries and "Emergency Start".  I imagine Emergency Start is like "Both" on my old boat.  Something I don't understand is the starboard switch is always lit green, no matter what position.  The port can be turned on and off with the rocker.  Why is that? And why would you do that?

The 2nd photo is back in the engine room above the 3 batteries.  There's another "Marine Electric Battery Switch" in the starboard corner with the Generator battery.  Despite the picture, these are both in the "Auto" mode.  What are these doing and is "Auto" the correct position?  Being deep in the engine room it's not something you're easily going to be making routine changes to.  And this "Port Battery Switch" (on the left), how does this differ from the "Port Engine Battery Switch" rocker in the cockpit panel?

I assume this is similar to other Rinker Cruisers (and probably other makes?).  How do you manage your batteries with this setup?

LaRea

I'm curious if you actually have four separate batteries (port, stbd, house and genny).  On most twin-engine boats, the charger only has three outputs (port, stbd, house).  The genny usually runs from one of the starters.  

My guess is that the stbd battery is the starter for stbd + genny, and two of the batteries on the port side are wired in parallel as a house bank.  It would be worth the effort to map out those battery cables and figure out what's going on.

Spyderweb

Of the 3 in a row on the port side, the front 2 are connected by a red (+) cable. Would that actually be a house bank?

Willhound

If hooked positive to positive and negative to negative and then leads from one of the batteries heading off to the switch, then yes, likely a house bank wired parallel. Keeps it 12v but "doubles" the amp hours assuming both batteries of comparable capacity, condition and age.

JimGuy341

We have a new to us 2008 350 EC with the same battery and switch set up.  

Spyderweb,  were you able to find an answer on the engine compartment port battery switch?  Should it be on AUTO or ON?  Our situation is, with the port  battery switch on AUTO, I have low volts to the port engine.  Switch it to the ON position and everything works fine.

Spyderweb

Don’t know that I ever got an understanding of what should be with the switches, but I just checked now and all 3 switches are in the ON position.  Worked fine that way all last year and no problems this year.

JimGuy341

Spyderweb said:

Don’t know that I ever got an understanding of what should be with the switches, but I just checked now and all 3 switches are in the ON position.  Worked fine that way all last year and no problems this year.

Great.  Thanks for the feedback!