blue sea add a battery installation

[Ryan1135]

Hello all, I am new to the Moomba crowd. Bought a 2007 mobius XLV GG edition last fall. I have been wanting to add a battery switch as the current 2 battery has no switch, but some sort of 50A breaker that shuts down the boat but still allows the radio to draw power and was slowly killing both batteries according to the previous owner. I am at a loss for how your supposed to ground this blue sea ACR. in the provided schematic its showing a negative bus bar that is grounded, but i have been unable to find any similar grounding in the electrical system. I also cant trace the wires leaving my alternator, they must hit a junction somewhere under the floor and split to one of the wires on my batteries. The picture provided shows the current system, the batteries were linked in parallel and that was about as fancy as the system was. If im understanding the set up correctly the 2/0 gauge red wire will be to my "starter" pole, and the rest of the various gauge reds would be combined and put onto the "House" pole. and then the batteries would be connected respectively. Im assuming that the alternator is already feeding the positive connection of my battery? Did any of you run the start isolation to your ignition? And lastly how are you grounding this system? any help is much appreciated.

Battery wiring.jpg

[schwan]

I added an acr to my system last spring on my 16 mojo. My boat has a bus bar so I grounded to that. I also ran the starter isolator. You should do this, I forget the specifics, but I believe you will have issues if you turn the engine off, then go to start in back up too soon. Your red in your pic is going to the starter/alternator, so you're good there. You will probably want to put in a bus bar just to make it easier. Another thing I will say is that the acr wasn't hard to do, but it really requires you to pay attention. Everything has to be perfect for it to work. Good luck!

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[Branden967]

The red wire coming out on your pic is from the alternator and would be you power supply in. The black is your ground and typically comes from the engine block. Connect the black to your negative post on your new battery or batteries all together. Which ever switch you install they typically grab the hot from you alternator in and branch it to off to the positives of your new batteries. Those systems don’t usually mess with the ground sides. 2 gauge wire is fine just make sure you secure it very well.

[Ryan1135]

yea i think that ive been looking at this schematic too long, i searched the forums and have seen others asking similar questions. I just do not comprehend how my current system is working if i need to run a new ground. I have to assume one of the two black wires going into the hull are grounded to the block somehow. In the picture the white, red, and black wires that are running left or up are all for stereo shit, but the 2/0 gauge and the one next to it go to the boats system, so one or both of those have to ground somewhere already. If my small brian is starting to work again, i think i should be able to run all the black wires in this picture to a bus bar and the system would be grounded based on the fact that the current system is grounded?

[schwan]

I would say, buy a bus bar for your negative grounding, since your current system is grounded, and you run that large black to the bus, you are now grounded and you have more poles to ground to that. I'll attach two photos, one explains why you want to run the start isolator, and another has a red arrow showing where to connect your red radio wire, that way if the radio is connected there and you throw the switch to off, your radio can't drain the battery anymore.

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[Ryan1135]

I would say, buy a bus bar for your negative grounding, since your current system is grounded, and you run that large black to the bus, you are now grounded and you have more poles to ground to that. I'll attach two photos, one explains why you want to run the start isolator, and another has a red arrow showing where to connect your red radio wire, that way if the radio is connected there and you throw the switch to off, your radio can't drain the battery anymore.

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Thanks a lot for the responses man, the help is much appreciated. I am used to doing AC current electrical so DC is like a foreign language, I thought the black wire was a negative, like the wiring in your house, so that kinda threw me off. I’m gonna do exactly what you said, I had assumed the blacks would need an amp rated bus bar, but i won’t if I’m understanding correctly. I was looking for a green ground wire all over the boat and the motor haha. It looks like you used 2/0 welding wire in your pictures. And I’m assuming those those breakers from the acr are 100 or 150 amp depending on your alternators amp charge. This seems a lot easier than I was making it sound yesterday.

[schwan]

I can't remember the sizes of the wires I used, but I remember over sizing one step just in case. Also I forgot I have the batteries in the garage, I used 150 amp fuses on the terminal, these work well.

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[MLA]

Electrically, none of the existing grounds, will be changing. The only new ground for the ACR control.

@schwas, is it na optical illusion or are you just making use of 3 posts on the dual circuit plus switch?

[schwan]

Just an optical illusion of me being restricted to existing cable length!

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[MLA]

Just an optical illusion of me being restricted to existing cable length!

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Good to know.