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Author Topic:   Moving Batteries to the Console
DjPro posted 04-24-2006 08:47 PM ET (US)   Profile for DjPro   Send Email to DjPro  
I am in the process of moving my batteries to the console on my '79 V-20 Outrage.
Can anyone tell me what gauge wire I need to use to make the connections?

Battery #1 neg to Battery #2 neg
Battery #1 pos to switch distance less than 24"
Battery #2 pos to switch distance less than 24"
Switch to console fuse board less than 24"
Switch pos to motor fuse 8'
Switch pos to motor 11'
Neg to console board less than 24"
Neg to motor 11'

Does this look right? I think I have something screwed up.......

jimh posted 04-25-2006 08:51 AM ET (US)     Profile for jimh  Send Email to jimh     
There are many prior discussions of this topic.


jimh posted 04-25-2006 08:52 AM ET (US)     Profile for jimh  Send Email to jimh     
jimh posted 04-25-2006 08:54 AM ET (US)     Profile for jimh  Send Email to jimh     
Check the installation manual for your engine. This typically contains advice on cable size.
jimh posted 04-25-2006 08:56 AM ET (US)     Profile for jimh  Send Email to jimh     
To provide the proper voltage for starting, you have to keep the resistance of the entire system as low as it was before you lengthened it. This means you have to replace all the current cables with larger gauge cables. If you increased the length by double, you have to increase the wire size to the next larger size to maintain the same resistance.
DjPro posted 04-25-2006 09:33 AM ET (US)     Profile for DjPro  Send Email to DjPro     
Thanks Jim. You have a very helpful site. I could read it for hours.

Does it look like I have the concept right as far as necessary cables?
Does it make a difference which neg cable battery goes to the motor?

Chuck Tribolet posted 04-25-2006 12:19 PM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
You are basically going to be dealing with two gauges of cable.
One very heavy for the cables that will carry starting current. We'll call this starter gauge. This will be
unfused. The other will be lighter gauge (but still fairly
heavy), and fused and sized to the sum of the rest of the
loads. 30A and 10 gauge, or 50 A and 8 gauge would be
typical. We'll call this light gauge.

The two battery negatives should be tied together with a
short starter gauge cable. There should then be a starter
gauge cable from the primary starting battery to the engine
ground. It would be really cool if you could figure a way to
get two battery connectors on a single cable (one less point
of failure, shortest cable when starting with the primary
battery, one less slight resistance from the connection
when starting with the backup battery).


jimh posted 04-25-2006 02:58 PM ET (US)     Profile for jimh  Send Email to jimh     
Be certain the negative terminals of the two batteries are bonded together with a conductor which can carry the full starting current load. In a small boat installation it is typical to just bind the two battery terminals, then one or both of them is used as the negative common point for the high-current distribution.

In my own boat I have the two battery terminals connected with a 2-AWG conductor. The engine negative lead is connected in parallel at one of the batteries. I also have a separate battery negative distribution buss, which is connected to the battery negative terminal with an 10-AWG. This terminal serves as the common point for other devices connected to the battery negative terminals.

I'll try to make a sketch and post it.

DjPro posted 04-25-2006 07:59 PM ET (US)     Profile for DjPro  Send Email to DjPro     
I understand everything so far. My '79 does not have a green bond wire but the tank is connected to the read plate in the back and the front of the tank is connected to the gas fill.
Where I start to get confused is the black box on the starboard gunnel.
How many cables run to the motor?
Am I correct in think that 2 positive cables run to the motor one from the battery switch which would be heavy gauge and one from the starboard black box? Does that box also get a neg cable from the battery and one out to the motor?
jimh posted 04-26-2006 07:14 PM ET (US)     Profile for jimh  Send Email to jimh     
What is "the starboard black box"?
DjPro posted 04-27-2006 03:21 PM ET (US)     Profile for DjPro  Send Email to DjPro     
tilt trim control box, which I'm trying to relocate to the console as well but don't know what gauge wire to replace it with.

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