battery lead length

[crokit]

Hello...I have a houseboat that is 38 ft long...I have a starting battery located at stern and would like to locate my house battery at the helm as all my fusing and house controls are there...my question is ...running a 1986 70hp johnson outboard would i be able to run a battery lead to the helm (which is about 32 feet away from motor)and be able to charge my house battery effeciently?I'm thinking of using the steel frame of the boat as a ground source . thanx for any responses

 

[rickdb1boat]

Re: battery lead length

You'd need some huge wire(4/0 minimum) and along with that, the idea of using the boat for a ground is a no-no. Might not be good if someone grabbed the rail and got zapped....Got a generator onboard?

 

[Paul Moir]

Re: battery lead length

If he's not starting, then he would only need a smallish wire. What's the alternator on that 6 amps?<br />#10 or #8 would be my first picks, not so much for ampacity but for durability and future use. Also a battery isolator is just the part you need to make it all work. Get the cheapest you can find - you're only charging a few amps not 70. <br /><br />If you were using it for starting too, extrapolating from OMC's guidelines you would want 3/0 at up to 40'. 4/0 wouldn't be a bad idea.<br /><br />Never, ever use parts of a boat as current carrying conductors. You're just asking for serious electrolysis problems if you attempt it. There's good reason even the cheapest of boat manufacturer's spring for the extra wire, and there are code rules to prevent you from doing it.

 

[rickdb1boat]

Re: battery lead length

If he's not starting, then he would only need a smallish wire

True enough.....

 

[crokit]

Re: battery lead length

Thanx for the info and advice....my other concern is overloading the charging system on the motor...and I believe it does have a 6 amp output.