Battery Cable Length

aero3113

I was looking at my engine compartment this morning and it looks like my battery cables can be re-routed and shortened a lot. Shouldn't shorter cables be better (Less resistance)?

Handymans342

Depends on size of wire

aero3113

Handymans342 said:

Depends on size of wire

2 gauge for the batteries and 0 for the starter.

MarkB

Yes shorter better. But resistance with be lower per ft for bigger cables.  So the benefit depends on the size of the cable.

Michael T

IF the cables have the same construction and composition then shorter is always better, even by a foot as resistance and heating are reduced. Going up a size using quality marine cables, as short as you can comfortably run is THE best way to go.....and yes, that can make quite a difference, particularly for cranking the engine(s). Another huge factor is the quality of all ground connections. these often get overlooked and are a source of so many wiring headaches!. Loose  connection both - & + create another set of frustration. very simple fixes to avoid problems ranging from troublesome to dangerous!

aero3113

I started replacing all of my cable ends today. When I cut back one of the ground cables there was moisture that I could actually see about 1 inch back. With the new ends on I used heat shrink tubing that has an adhesive in it that seals the wire when heated.

Check out how bad the starter cable was!

Cableguy Greg

That could leave you stranded... If you have moisture in the cable, I would suggest replacing the entire cable. The moisture can get sucked back in and corrode the cable where you can't see it.

aero3113

I agree, there was plenty of extra cable that I cut back. I'm pretty sure it's moisture free now.

Michael T

Hard to say aero. That doesn't look like tinned marine cable that thwarts, to some degree, moisture wicking. Corrosion like that is often like mold it's hiding there until it manifests itself. Moisture is drawn along the cables by the electrical  current so it might be a fair way along the cables.

What you have done will be a big improvement for sure. If you replace the cables at some point I respectfully recommend tinned higher quality cables as they IMO are worth it. BTW I cringe when I see the cables lying in bilge water as it is going right through the cable casing and being drawn along inside the cables.

aero3113

Thanks MT, the starter cable is 2/0 tinned marine cable and the battery cables are 2 gauge tinned marine cable. I made sure before I replaced the ends.

Michael T

Good news! Great work!

aero3113

I got to wake the boat up from her winters nap today! With the new cable ends and starter it fired on the first revolution. Seemed like a really strong start with no hesitation at all. Can't wait to get in the water!