Battery: The ol' 1 and a 2...

geary126 · #1 (**permalink**) 07-17-2007

So, I've got two 12 volt deep cell 75 amp batteries connected in parallel, sitting under the companionway in some battery boxes. This was PO's doing (along with war, famine, and just about every other malady..!)

Anyway, I hate the look of this thing, and I'm also attempting to rewire the panel, located above the chart table.

there's a spot, i think, for two batteries under the table, so I'm going to try them there.

The question is, with a modern 1 2 both off switch, doesn't the circuitry of the switch wire the batteries in parallel, or separate them based on the settings?

Right now, the batteries are wired together, literally, and I'm thinking this nullifies the 1-2-both thing.

Thanks, guys, as always.

Freesail99 · #2 (**permalink**) 07-17-2007

The "1-2 both thing" is for your house bank and your STARTER battery. Most have a seperate battery to start the engine ......... just in case.

BTW, My electric panel is located behind the companionway steps, and I plan on moving it the navagation area.

USCGRET1990 · #3 (**permalink**) 07-17-2007

1 or 2 the batteries are separate. Both..they are parallel. At least in my book anyway...

geary126 · #4 (**permalink**) 07-17-2007

I know, but the question is, should the batteries be connected in any way, or just connected to the switch?

camaraderie · #5 (**permalink**) 07-17-2007

If all you have is those two batteries...USCG is correct. If you have a separate engine start battery...wire your companionway batteries in parallel to each other and to ONE position on the switch...and wire the starter batery to TWO position on the switch. That way if your starter ever fails you can go to BOTH to start the engine.

Freesail99 · #6 (**permalink**) 07-17-2007

Quote:

Originally Posted by USCGRET1990

1 or 2 the batteries are separate. Both..they are parallel. At least in my book anyway...

Sorry I wasn't clear, this is what I was saying in my own way. Maybe there is a reason I keep getting emails about classes for English as a second language.....

sailingdog · #7 (**permalink**) 07-17-2007

From the sounds of it, the two batteries were in separate banks, and one was used as a starting battery and the other as the house bank. However, I would look into getting at least one more battery, since 75 Amp-hours is an awfully small house bank. It does depend on what size boat you're talking about, but for even a small boat that is used for weekend trips, you'd probably want a larger house bank.

Cruisingdad · #8 (**permalink**) 07-17-2007

Quote:

Originally Posted by geary126

So, I've got two 12 volt deep cell 75 amp batteries connected in parallel, sitting under the companionway in some battery boxes. This was PO's doing (along with war, famine, and just about every other malady..!)

Anyway, I hate the look of this thing, and I'm also attempting to rewire the panel, located above the chart table.

there's a spot, i think, for two batteries under the table, so I'm going to try them there.

The question is, with a modern 1 2 both off switch, doesn't the circuitry of the switch wire the batteries in parallel, or separate them based on the settings?

Right now, the batteries are wired together, literally, and I'm thinking this nullifies the 1-2-both thing.

Thanks, guys, as always.

Geary,

To answer your question, yes: The nature of the switch allows you to isolate or parallel the batteries. Wiring them in parallel before they get to the switch makes it null and void. You need to backtrack and see where all the leads are coming from. If you do have a seperate start battery, that might be the source of the second lead. However, is there a second lead on there at all?? Without backtracking, this conversation is hypothetical - and should be taken as such.

The positive of running your starter to the 1-2 switch and removing the house from one of the legs is the ease to switch between the batteries for a little extra house potential or for a little extra engine-start potential. THe negative is the careless captain/crew that forgets to take the engine battery off the selector switch and runs down all of his banks before realizing his error.

Did that make sense?

- CD

geary126 · #9 (**permalink**) 07-17-2007

okay. I think I got it. thanks, guys.

SEMIJim · #10 (**permalink**) 07-17-2007

I was under the impression that the off-1-2-both switch switched the batteries entirely. That is: Whatever the position of that switch, that was what was used for lights, starting, electronics, what-have-you. I had read somewhere that you always start in "both." I had assumed the idea there was to make sure you had plenty of amps for starting and to make sure both batteries would get a recharge from the engine running. Then, I thought, the idea was to use one-or-the-other for lights, electronics, etc., while under way, at anchor, etc., keeping the other as fully-charged as possible for starting.

Jim