Separate stereo batteries, can I ground them to my main battery?

[bobbobobbo]

The picture will explain it best. I have my main battery to start the boat, etc. Then I have two deep cycle batteries in parallel, that I'll charge at shore after a day out. These only run the stereo/amp.

My problem is my ground wire isn't long enough to reach to an engine mount. I can grab a new one, or could I simply attach the negative to the negative of the main battery, since it all goes to the same ground location? (would be much easier, green line in pic) Or would that somehow create a draw or link the two together in some way. As I want the stereo and main to be completely separate.

 

[MH Hawker]

i am sure the experts will be along, my one question is and it may may or not apply but is their any other inter connection any place

 

[Daboss81]

Just spend money and get longer cable

 

[bobbobobbo]

No other connection. Stereo batteries go to stereo, main battery goes to motor and everything else.

It's not the money, with where the batteries are it's not that easy to do and tie in neatly to an outboard. Especially when I'll be grounding to the same point the main battery is touching. So I figured I'd ask, whats the difference?

 

[Scott Danforth]

spend the money and make longer cables

 

[bansil]

It is its own "closed loop" correct? Stereo and amp grounds go to - post and bat goes to + post on deep cycle batteries

Why do you want to ground it to the engine?

 

[NYBo]

Unless you plan to install a battery switch (so you can use the stereo batteries to start the motor if the main battery dies, or to charge them from the motor) or an ACR, I don't see why you would want to do this.

 

[Scott Danforth]

to prevent electrical issues from having floating grounds.

 

[NYBo]

to prevent electrical issues from having floating grounds.

With no other interconnections, I'm not seeing how this would be an issue. But I haven't had my morning coffee yet.:distracted:

 

[ziggy]

As I want the stereo and main to be completely separate.

imho, then forget the extra neg. wire going to the start batt. there is no point that i can see. run you stereo pos. wire to the deep cycles pos. , run your stereo neg. wire to the deep cycles neg..... yer done. the stereo is isolated off the boat batt. the stereo has it's own power, the deep cycles. the boat has it's own power. the normal start batt. no interconnection between the two at all.

 

[gm280]

If you look at this from a noise point, I would forgo any ground connections between the engine battery and the stereo batteries. And that is because if the engine produces any spiking noise, even on the negative line, they would be transmitted to the stereo power supply. Why offer a source for noise? :noidea:

 

[Scott Danforth]

With no other interconnections, I'm not seeing how this would be an issue. But I haven't had my morning coffee yet.:distracted:

if it is completely separate, to never be charged by the motor, to never have a single piece of metal in contact with anything associated with the motor's electrical system in any way, then yes, by all means, separate it. just realize that a person touching the boat and touching the radio can become part of a circuit.

however if you plan on having the outboard ever charge it or a common multi-battery charger charge this and the other batteries, it needs to share a common ground, have a proper isolation and charge relay, etc.

 

[bruceb58]

just realize that a person touching the boat and touching the radio can become part of a circuit.

Agree with Scott. The potential difference can become very large.

 

[bobbobobbo]

I currently have the amp grounded 2 feet away on the pontoon railing. Many state to run the amp ground all the way back to the battery negative terminal on boats. Yet my stereo battery negative itself doesn't ground anywhere, but maybe that's ok?

I'm a bit stumped..

These were helpful:
https://www.crutchfield.com/S-LX5eob...on-a-boat.html
http://www.thehulltruth.com/marine-e...amplifier.html

 

[alldodge]

Don't even connect the negative to the start battery, now you have a boom box powered by two batteries. Just make sure the ground from the stereo and amp do not come in contact with the boats ground

 

[bobbobobbo]

Don't even connect the negative to the start battery, now you have a boom box powered by two batteries. Just make sure the ground from the stereo and amp do not come in contact with the boats ground

This makes sense. Does the stereo battery need to be "grounded" in any way? Or nah. It just runs the amp and head unit.

 

[Scott Danforth]

I currently have the amp grounded 2 feet away on the pontoon railing. Many state to run the amp ground all the way back to the battery negative terminal on boats. Yet my stereo battery negative itself doesn't ground anywhere, but maybe that's ok?

I'm a bit stumped..

These were helpful:
https://www.crutchfield.com/S-LX5eob...on-a-boat.html
http://www.thehulltruth.com/marine-e...amplifier.html

using the boat as a ground is a good way for the aluminum to disappear. run a dedicated cable

 

[bansil]

if stereo stuff is isolated from boat (amp and stereo not mounted/screwed to anything conductive) you could grab the boat and bite the positive cable and nothing will happen if there is no contact with boat.
Grounding amp or stereo to the hull is bad, keep them seperate, completely.

Example would be just mounting amp to speaker box and mounting radio chassis to wooden panel(no metal contact)

Take ground of stereo and amp, connect to neg post, take pos from amp and stereo connect to pos post, blue wire to amp turn on, and then speakers and preamp cables connected. As long as nothing conductive touches boat no issues and no floating grounds

Def. Unhook ground to hull not needed


if your bored check the website noshockzone michael is very good and post on all rv/camper and bus sites

 

[Silverbullet555]

I currently have the amp grounded 2 feet away on the pontoon railing. Many state to run the amp ground all the way back to the battery negative terminal on boats. Yet my stereo battery negative itself doesn't ground anywhere, but maybe that's ok?

I'm a bit stumped..

These were helpful:
https://www.crutchfield.com/S-LX5eob...on-a-boat.html
http://www.thehulltruth.com/marine-e...amplifier.html

That makes no sense. If you are grounded to the rail where is the rail grounded to? Did you ground your house batteries to the rail? Is the boat already grounded to the starting battery?

You want your power and ground to match capacity because they both carry the same thing. An aluminum tail has a much higher resistance than copper wire.

When I built our stereo I ran 00 power and ground wires from the house battery to distribution blocks near the amps. Then I connected grounds and installed the ACR so they both charge.

 

[bruceb58]

There is no problem grounding the hull. That is called bonding to keep it at the same potential as everything else. Just don't hook anything else to the hull so that the hull is used as a conductor.