Dual Battery

Okie Boarder · Ladies Man Joined: 03 Mar 2008 Posts: 10056 City: Edmond

I'm planning on reinstalling both batteries like I had last year. The way I did it last year was the "house" battery was only connected to the stereo and amp and it wasn't connected to the engine. I threw it on the battery charger at home. This year I'd like them both to be able to be charged by the engine. Here's my set up:

Starter Battery:

Marine Starting (24 Series)
625 CA
500 CCA

"House" Battery":

Dual Purpose (Starting / Deep Cycle)
875 CA
205 Reserve Capacity

**Goal**

Engine always charges batteries individually when the engine is running with priority to the starting battery. When engine is off the drain is always on the "house" battery, or never drains the starting battery below a certain level.

I've started reading about battery switches, relays, voltage sensing switches and voltage sensing relays. It kind of sounds like I should use a switch and VSR, but I'm not sure.

Can anyone provide some feedback or share your setup?

MobiusLSV · Newbie Joined: 06 Sep 2009 Posts: 33

I would recommend a Blue Sea Systems 7650 ACR (automatic charging relay) Add-A-Battery. I've had one on my '07 Moomba LSV for two years without issue. The battery switch included only has OFF/ON/COMBINED so there's no messing with it throughout the day. It charges whichever battery needs charging.

http://bluesea.com/category/2/productline/overview/329

Okie Boarder · Ladies Man Joined: 03 Mar 2008 Posts: 10056 City: Edmond

That's one of the ones I've looked at.

Are your batteries the same style and size or different like mine?

Are those breakers over towards the left of your picture?

I assume the combine puts both batteries together for starting just in case you need the extra cranking power?

MobiusLSV · Newbie Joined: 06 Sep 2009 Posts: 33

I have two Interstate batts, one cranking GRP24 (starting) and one deep cycle GRP27 (house).

The breakers you see are for the starting circuit (factory) and one i installed for my inverter. There are two others however for the batts from the ACR behind the wall. Each battery circuit needs fused or thermal protection going to the ACR. The ACR auto isolates them when stopped and only connects for charging when needed.

Exactly, combining puts both together in case the starting batt is low.

pet575 · Posted: Mar 01, 2010 12:00 pm Post subject:

I don't have a specific product recommendation, but a setup similar to the one MobiusLSV, is throwing at you is the way I would go as well. If I'm not speaking out of school too much, it uses a combo of an isolator and a switch to get you set up this way. I've also seen some systems use an isolator and a combiner to get it done.

Mine has an individual Perko switch on it with 1, 2, BOTH, OFF as the choices. But, this is all manual controlled under this setup so that if I want 2 only to charge I have to turn the switch to 2. Same thing with use. MobiusLSV's setup, the way I understand it, is that it charges the batteries "as needed" without you selecting anything other than which battery you want to pull power from.

If I'm not understanding right, please correct me.

MobiusLSV · Newbie Joined: 06 Sep 2009 Posts: 33

No Pet your absolutely correct, it's all on auto. Turn the switch to on to start the day and to off when done, that's it. Much easier than the manual style.

Okie Boarder · Ladies Man Joined: 03 Mar 2008 Posts: 10056 City: Edmond

When you tunr it to off it disconnects the batteries from their circuits, right? Do you lose memory presets on your stereo?

kartman · Posted: Mar 02, 2010 6:56 am Post subject:

all you would have to do is run your constant power from the battery that wouldnt get shut off, or straight off the battery terminal.

pet575 · Posted: Mar 02, 2010 1:20 pm Post subject:

jjaszkow · Posted: Mar 02, 2010 3:10 pm Post subject:

pet575, how are your batteries configured? Is one dedicated to the stereo and the other to starting, or are they both wired to run either circuit?

I will definately be installing an ACR to charge the batteries in my next boat. I haven't decided which switch I will install however, since controlling which battery is receiving the draw appeals to me. The way I see it, I have the following options. I am leaning towards the first, but can see benefits to the second also.

1: Use the exact configuration that MobiusLSV reccomended, use a deep cycle battery to power the stereo and a standard battery for starting.

2: Automatically charge batteries with the ACR, and select between two deep cycle batteries using the standard Perko switch.

Grit dog · Newbie Joined: 18 Nov 2009 Posts: 18

I'm going to use the Blue seas ACR as pictured above. My setup is similar. Start battery runs everything on the boat EXCEPT the amps. Amps run off of the house battery and teh 2 batteries are not connected to each other.
Unless you want the capability of shutting off the batteries or the ability to use the house battery to start the boat, you don't need the Perko type switch. The ACR will automatically combine your charging effort to the battery that needs it and keep a drained battery from sucking power from a good battery.
I don't see any need for the Perko switch unless you're worried about battery drain, in which case I'd be worried about teh cause of the drain.

pet575 · Posted: Mar 08, 2010 1:18 pm Post subject:

pet575 · Posted: Mar 08, 2010 1:19 pm Post subject:

Perko switch is nice so that you can control any drain that does exist by selecting one battery or another to be drained. That way, you always have some type of reserve power for starting in case whatever you are running while sitting around anchored for hours is drained.