Gauge wire for dual batteries.

[Hubboat]

I got a couple DP24's for my 1995 22' Angler Cuddy Walkaround.

The single battery resides at the stern, I want to put this new pair in the bait wells, to get some weight up front and give me a place to put the two. My plan is to attach two cables to the output of the switch, one heavy gauge to the engine starter (gauge I am curious about, factory cable looks like 4? gauge? And a thinner cable (8 gauge or so) to power the boat fuse block (current cable is only 14 gauge, lol).

I got this switch:
http://www.amazon.com/Perko-8501DP-Marine-Battery-Selector/dp/B00144B6AE

What gauge wire do you suggest for the starting cables to my 1994 200HP Merc 2-stroke? Also, how do you connect the current (short) starter cables to the engine? butt connect and solder? Or replace the whole cable from battery switch to starter?

Thanks,
John

 

[Silvertip]

Re: Gauge wire for dual batteries.

So you are going to have a total of three batteries? 1 Starting and 2 auxiliary? If so, the switch only accommodates two batteries so what's your plan? If you intend to use all three then two of them will need to be connected in parallel. And if that's the case, no two batteries are exactly equal so one will always draw down the other until they equalize. Not necessarily a bad thing but just be aware of the issue. ALL cables between the batteries and the switch MUST be the same size or larger than the battery cables going to the engine. The feed to the fuse panel DOES NOT get connected to any of the batteries. It gets connected to the COM terminal of the switch. It too, must be the same size or larger than the 8 gauge you currently have.

 

[Hubboat]

Re: Gauge wire for dual batteries.

Thanks for the reply, no I will just have two batteries, removing the one from the stern.

 

[fish_on_the_deck]

Re: Gauge wire for dual batteries.

If you had 4AWG before it would be wise to change to 2AWG for the longer run to minimize voltage drop IMO. there are calculations you can do to determine the voltage drop.

Best prices I've found on raw cable are here:

http://shop.newwiremarine.com/Raw-Battery-Cable_c14.htm

I usually just crimp and heat shrink my connections... I dont use solder.

 

[DianneB]

Re: Gauge wire for dual batteries.

I just moved the batteries forward in my 24' cruiser last fall and I used 0-Ga welding cable for the engine battery and common ground and 2-Ga for the house battery - I wanted the lowest voltage drop I could afford since I am cranking an old 6 cylinder. Good quality welding cables have an incredibly tough jacket. As an added precaution, since the starting cable is unfused, I ran all three cables in PVC conduit from the battery locker to the helm where the A-B-Both battery switch is located. The engine + and ground then carry on back to the engine. I use both crimp and solder together where minimizing resistance is important.

It was a deuce of a job feeding 3 heavy cables into conduit and routing the conduit unobtrusively through the cabin, not to mention dressing heavy cables is a PITA! but moving the batteries 24 feet on 0-Ga cable gives me as good cranking performance as the stern location on #4 cables did.