Dual battery factory wiring

[nitrodude24]

Does anyone know how the dual batteries are wired from the factory. I assumed there was a voltage sensing relay. When we were out this weekend on the lake I had a drained battery I had to combine to start after I combined the two batteries I had no more issues. I guess what I'm asking is the alternator put voltage to both or only the selected battery?

[David Analog]

The wiring scheme varies, unfortunately.
BEP is different from Blue Sea. One may use a conventional switch and the other may use a dual circuit switch.
Sometimes factory doesn't get it right.
Sometimes the ground is not connected on the relay which means the voltage sensing relay doesn't close and charge the second bank.
Keep in mind that if the stereo battery is depleted enough and the continued draw is high enough that the relay may attempt to close, bounce open and stay open, again resulting in no charge to the second bank.
A voltage sensing relay generally increases your dependency on AC shore charging.
Don't get me wrong. I'm a big advocate of a voltage sensing relay system. But they do have particular behaviors that can change under different situations.
Someone who knows them well should look the system over, confirm the operation, test your battery, and fully explain their operation to you.
There are those times when the manual switch may be required even though this is intended to be a fully automated (set it and forget it) system.

[viking]

I've seen more dual batt systems wired WRONG from factory (from other manufacturers as well) than actually wired correctly. And I'm no expert by any means but can decipher a manual and follow diagrams pretty good. I'd pull out the paperwork & double check everything.

[mmandley]

Moomba doesn't wire using a ACR, you have to add it after you own the boat.

They use the simple 1 2 Combine switch and that's it.

This means You have to select the battery you want the alternator charging.

What I used to do was keep it on Combine all the time. This allows the Alternator to see both batteries as 1 and charge them all the time.

Then when I want to park and Party cove I would select it to my Stereo battery only protecting 1 battery for starting. Once I restarted the boat I would Combine the batteries again for charging.

[nitrodude24]

Thanks Mike and everyone else you guys answered my question and gonna force me to spend some cash .Lol

[North Woods Mobius]

Moomba doesn't wire using a ACR, you have to add it after you own the boat.

They use the simple 1 2 Combine switch and that's it.

This means You have to select the battery you want the alternator charging.

What I used to do was keep it on Combine all the time. This allows the Alternator to see both batteries as 1 and charge them all the time.

Then when I want to park and Party cove I would select it to my Stereo battery only protecting 1 battery for starting. Once I restarted the boat I would Combine the batteries again for charging.

Thanks mmandley - that's the first I heard that you need to be running 1+2 on the battery selector switch to charge both batteries, but I guess that makes sense when you think about it..... I have only ever run the boat on 1 or 2 (but not both) for fear of draining both batteries and getting stuck in an unfortuante situation!

[David Analog]

Thanks mmandley - that's the first I heard that you need to be running 1+2 on the battery selector switch to charge both batteries, but I guess that makes sense when you think about it..... I have only ever run the boat on 1 or 2 (but not both) for fear of draining both batteries and getting stuck in an unfortuante situation!

But you do understand that you cannot run in 1+2 while specifically at rest....only while underway.
You can drain both batteries simultaneously while underway on 1+2....IF....the combined draw (stereo, boat operations, etc.) is greater than the alternator output. That could include the depleted stereo or house battery draw after a long stay at rest. But for this to be the case the stereo would have to be extremely large.

[MLA]

Thanks mmandley - that's the first I heard that you need to be running 1+2 on the battery selector switch to charge both batteries, but I guess that makes sense when you think about it..... I have only ever run the boat on 1 or 2 (but not both) for fear of draining both batteries and getting stuck in an unfortuante situation!

The "have to" aspect depends on how ones particular switch and house (audio, etc) bank is configured and how you use the system. There are so many variables, it can get confusing and be misleading, reading about how one person uses theirs, without the context of how its wired. Proceed with caution, until you know those other pieces of the puzzle.

[jstenger]

Moomba doesn't wire using a ACR, you have to add it after you own the boat.

They use the simple 1 2 Combine switch and that's it.

This means You have to select the battery you want the alternator charging.

What I used to do was keep it on Combine all the time. This allows the Alternator to see both batteries as 1 and charge them all the time.

Then when I want to park and Party cove I would select it to my Stereo battery only protecting 1 battery for starting. Once I restarted the boat I would Combine the batteries again for charging.
I agree with Mike's post. I do the same thing. No issues at all last year. Just remember to take the switch off of 1+2 when sitting and partying.

[Jason05216]

Let them both run down once because you didn't change the position. You won't forget again. I did that once in our other boat and it's pretty well burned in the memory banks to change the battery switch whenever we stop and turn off the engine. Pretty helpless feeling when you try to start and all you get is that click.