Battery Cable routing

[flounderpounder225]

During my repower and refurb on the 245 Osprey, I moved the batts to the Console.  I had access to free marine grade tinned 4 AWG wire, and made all new cables with soldered lugs and heat shrink, pulled everything through the rigging tube, along with all the new harnesses for the yamaha etc.. etc... the tube is REALLY stuffed.  Now, during the shakedown cruise I am noticing a voltage drop when cranking the engine, the engine spins fine and starts with no issues, but a couple times shut my GPS off for low system voltage.  I did a voltage drop test at the stern terminal studs where I made my connection for the cable run to the console, and the initial hit of the starter was dropping my system voltage to around 8 something volts for a second or so.  Yesterday I fabricated two small #4 cables and took one the batteries to the stern and hooked into the pos and neg studs, cranked the engine, and only dropped to 11.5, a good acceptable number.  So, today I will go to each terminal connector and use the correct crimpers and hopefully increase some connectivity in the primary battery circuit.  

Here is the question, IF I find that the #4 is simply going to result in too much V-drop, AND I cannot fish #2 wires through the tube, is there another route to the console, IE; along the sides, even if I had to install some access covers?  The current run of #4 cables as it is rigged right now is about 17 feet (times 2) or 34 feet for the entire circuit.  Thanks for the input.
Marc

[fitz73222]

Hey Flounderpounder,

What are the CCA`s for your cranking batteries. When you are adding that much length to the starting circut a 650 amp battery may not be enough through 17 feet of cable. You may need to upgrade to 900 CCA`a or higher to limit the cranking voltage drop.

[seabob4]

Marc,
Realizing the 4GA was free, that was pretty tempting.  But I'll be honest with you, I think you should've gone with 2GA.  We had an issue with weight in the stern of our Prolite 18 Flats, which neccessitated moving the batt to the console.  The round trip was probably no more than 22', yet ALL our engine suppliers (Merc, Suz, Honda, Etec) required us to use 2GA.

Sorry about that... :(

[Mark Sr]

Flounderpounder,

I also have a 245 Osprey T.M. I am having the same problem with voltage drop and starting the engine.My batteries are under the console.One starter and one deep cycle.I have to put it on all to start.If I leave it on #1(deep cycle) it's not enough to crank the engine and shuts the gps off.My buddy who is an electrican told me I should put two starter batteries in the back and leave the deep cycle under the console for accessories.Only use the starters for starting and nothing else.Any input helpful.

Mark Sr

[John Jones]

No need to move batteries out of the console.  On my 22-2 CCP I bit the bullet and ran 2/0 cables.  Note that that is not 2 ga.  There is a huge difference.  I had zero issues with voltage drop.  If the wire is big enough you could put them in the bow.

[seabob4]

OMG, ABYC E-11!  

[flounderpounder225]

Thanks all, for the replies, I just came in from crimping all the terminals that were just soldered, hoping hoping... that I would gain some voltage, but as I had already figured that didn't happen.  SeaBob, as they say, nothing is free, and the #4 cable turned out that way.   As far as cranking speed and amperage, I'm not having any issues (yet) I have two of the duralast dual purpose marine batteries, 1000 CCA each, and from the sound of it, you would never guess there was an issue, but the volt meter tells a different story.  The issue is the voltage drop when cranking which will eventually damage the starter.  So, I have two options at this point, as a first line of attack, I am going to try and feed one more set of the #4 wires through the tube to the console, basically doubling the capacity for the primary POS and NEG runs to the engine.  If I cannot get them through, then I will buy the #2 and pull through using the existing wire as the guides.  I should have listened to that little voice in my head back months ago.... "Use #2"  
Marc

[flounderpounder225]

Mark SR
You asked for any input, and there was some discussion of different batteries for my voltage drop problem.  For the last 2 boats I have owned, I have always used the Autozone Duralast Dual Purpose marine batteries, aside from the blue top optimas IMO they are the best batteries for the dollar out there, at 1000 CA and have some deep cycle capacity they are great, I have never had to replace one..  In my situation, the engine spins and starts fine, but over time, a low voltage condition will burn the starter up, and it will begin to drag, because the windings are breaking down and it will begin to draw more and more amps.  If you have access to an DC inductive (clamp on) amp meter you can slip it around the battery positive cable going to your starter and watch it when you hit the key, initially it will spike high, then come down and stabilize as the engine cranks.  My 250 HPDI is drawing a peak of 225 initially, then dropping to the 150-175 range.  According to the dealer, this is a normal draw.  I have decided I am just going to pull #2 cables from the stern to the console and be done with this issue.  You didn't mention what size cable is running to your console, but from your description, it also probably #4, which is common sized battery cable for outboard applications, when the batts are in the stern.  You said you have to switch to both batts when cranking, what you are doing is putting those 2 batts in a parallel arrangment, which is combining the total amp capacity of both your batteries.  If you have been operating for some time with a dramatic voltage drop condition like I am experiencing, and slowly over time your engine is requiring more amps to crank, you may have already done some damage to the starter.  You could perform the same test I did, disconnect your dual batteries at the stern connection point.  Put a good battery at the stern, I don't know what your connections are, mine I used a two stud bus bar screwed into the transom, and made my connection from the engine cable, to the batt cables going forward?  Anyway, either get a couple short battery cables, or even a set of GOOD large jumper cables and connect to your junction point and crank the motor, more than likely it will spin easily on one battery, what you have done is eliminated the long run of wire and proved the problem out?  Hope I didn't get too far off course with all this.  Good luck.
Marc

[slvrlng]

Well said !

[Mark Sr]

Flounderpounder,

Thanks for your explanation.I didn't anwser you earlier because I was away.As you said,I don't have #2 wire but that will be changed and my buddy said I should put in a 3 battery isolator which will keep things charged.Great info.

[flounderpounder225]

Well, the voltage drop issue is fixed, Just thought I would follow this post up.  I bought #1 AWG from genuinedealz.com, 28 Ft of Yellow, and 20 Ft of Black, it worked out just the right length for all the runs from the batts in the console to the battery switch which I mounted in the glove box.  After soldering and crimping all the new lugs, and making the connections, now while cranking I am only dropping to 10.5 - 11.0 volts, rather than 7.5 - 8.0 which is where it was dropping.  I can live with that.  Hope everyone has a great day tomorrow on the 4th.  
Marc