Aluminum Boat Wiring Questions

[Thuggin4Life]

I am redoing my aluminum boat and adding some extras. I was wondering if i should ground all my electronics to the boat or to the batteries? Also I was gonna use 2 batteries to power all my electronics and was thinking i could wire them in paralel and still have a 12v system and run all my electronics off of a post that draws off of both batteries at the same time. Any problems there or should this be fine?

 

[BoatNoobie]

Re: Aluminum Boat Wiring Questions

from all that i've read. You want to ground it to the battery.

 

[Thuggin4Life]

Re: Aluminum Boat Wiring Questions

I also stumbled onto this on another forum... "AND MOST IMPORTANT....

NEVER CONNECT ANY PART OF DC AND AC TOGETHER....

Because some devices like chargers have been known to short in such a way to send some live AC thru DC ground and kill people in water or Boat that are AC ground according to ABYC."

I was planning on mounting a battery charger to the battery and leaving it hidden in the boat and just pluging it in when the boat is at home in my garage. any concerns? thanks

 

[Thuggin4Life]

Re: Aluminum Boat Wiring Questions

from all that i've read. You want to ground it to the battery.

Thanks i posted this then started doing the research so far most agree to not use the boat as a ground but there are a few that swear by it but the are boat builders of big yahcts.

 

[Silvertip]

Re: Aluminum Boat Wiring Questions

If you have an electric start outboard motor that is bolted to the boat there is a pretty good chance an electrical connection between the hull and the negative terminal of the battery is made by default. But no. Do not ground to the hull. Leaving a battery charger in the boat is not an issue so long as the location is well vented and that the charger is a sealed, ignition protected unit. A battery gives of hydrogen gas and a spark can make it go "kaboom".

As for paralleling batteries, that is also not recommended unless you have a switch to separate the two. Two batteries are never identical in capacity so the weaker one will always suck down the stronger one until both are equal. Beyond that, we can't offer more advice since we have no idea what electronics you have, electric start? Total of three batteries (1 starting and 2 accessory or 1 starting and 1 accessory). Details needed.

 

[Thuggin4Life]

Re: Aluminum Boat Wiring Questions

I was gonna put the 2 batteries i have both are walmart marine batteries of equal size and all that. I was thinking i could wire them to a common post and run everything off of that. I am going to buy a switch board from cabelas that has 5 switches and a cigarette lighter. As for the location of the batteries i was gonna put them under the bow bench( i have a 12' deep wide welded western) and was gonna sprayfoam them in. I am using sprayfoam instead of the old foam that was there before. For accessories I have a fishfinder/gps,trolling motor,stereo,cabin lights, and nav lights. was thinking I am gonna have to make a 5 sided box to set the batteries in to keep them level. as for the charger i was gonna mount it under a seat in a sealed box with only the wires coming out. ones on the batteries and the plug coming out in a gasket type thing i got made to access the plug. someone also said i could just charge the batteries through the cigarette socket. so would it be bad to have my batteries not vented and sealed in with spray foam? and would it be bad to have the charger sealed up in a box surrounded by spray foam?

 

[Silvertip]

Re: Aluminum Boat Wiring Questions

You really need to rethink this. Why are you foaming everything in place? Batteries cannot be in a sealed area as they off-gas during charging. That gas needs to be vented. Your battery charger gets hot during charging. It needs air circulation so it cannot be in a sealed box much less surrounded by foam. It doesn't matter if you have two batteries that are identical in model number, brand, size, type, etc. They simply will not have identical capacity. Besides, you don't need to parallel them. Since you are installing some sort of switch panel, why not have a three position switch that lets you select battery 1, battery 2 or OFF. That way you don't have to worry about one battery drawing down the other. You don't need a big Perko dual battery switch for this. You could also add a voltmeter that monitors the battery you have selected. When it drops below 12 volts switch to the other.

 

[Thuggin4Life]

Re: Aluminum Boat Wiring Questions

So maybe instead of having the 2 6 gallon tanks behind the rear bench i could keep 2 batteries there with 1 tank and always leave with a full tank and take them both for a weekend trip. have permanent wires that go to the batteries that can be disconected to remove the batteries and put a switch before the circut board. thanks and then i can keep the charger out of the equation. thanks.