Change Battery Location

rbamat

Recruit
Joined
Feb 7, 2004
Messages
4
I have a 1984 25' Mako center console. It now has two batteries located in boxes at the stern of the boat. Would like to move them into the center console (about 10' from motor). Is this a good idea? What size wire would I need for the starter cable. I have a 1989 225hp Yamaha on the boat now and am thinking of going to a 225 Honda 4 stroke.
 

Paul Moir

Admiral
Joined
Nov 5, 2002
Messages
6,847
Re: Change Battery Location

Although a quick calculation shows #10 will work on a fresh charge and a sunny day, use #6 or #4 (better). The real question is how much performance you want in non-ideal conditions, like as the wire corrodes or the battery is low. I find welding cable to be very easy to work with since it's so flexible.<br /><br />eg, Say your starter draws 150A and your cables wind up being 10' long:<br />#10 = 1.77 volt drop along your cable<br />#6 = 0.7 volt drop<br />#4 = 0.44 volt drop<br />Generally a starter will not start the engine if it's getting much less than 10v to it's terminal. On cold days, your battery's voltage will drop from it's (full charged) 12.6v.
 

rbamat

Recruit
Joined
Feb 7, 2004
Messages
4
Re: Change Battery Location

Thanks for the info. Should I fuse the cable and if so what amperage and type of fuse should I use?
 

snapperbait

Vice Admiral
Joined
Aug 20, 2002
Messages
5,754
Re: Change Battery Location

Just did exactly that on 22' mako... <br /><br />Your battery cables are going to end up being nearly 18-20 feet long by the time you route them from the console back to the motor leaving enuff slack to turn the engine... If you have a battery switch in the circut then add a few more feet of cable there... I'd highly suggest 2 gauge battery cables, bare minimum...<br /><br />No fuse in the engine battery cables...
 
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