relocate start/house batterys (two) from aft. deck to forth deck.

I would like to relocate start/house batterys (two) from aft. deck to forth deck.

2004 Johnson 175HP model J175PLSRB

?1.can I extend start battery cable by 17'?

?2.what awg cable size? the orginal cable connected to engine is kindof thin.

thanks TB

 

The power rating should be about 1.2 kW. That means that the current will be 90A or so. There is a brief current surge at the start, but is not extremely critical. Try this calculator with 10% voltage drop:
Circuit Wizard - Blue Sea Systems http://circuitwizard.bluesea.com/

 

I entered the 90amps w/ 27' of cable thats 10' of orginale start /extended17' total lenght 27'

result was awg1

wonder how much voltage is lost?
thanks TB

 

10% if that is the value you entered. You can change that to the maximum allowable, but I would consider 15% about the most.

 

are you saying I lose 10% of the voltage?

 

You lose whatever you enter in the calculator. It gives you the gage of wire that will generate that voltage loss at the rated current

 

For the calculator, you have to add together the positive and negative run, so 54 feet? in your case. You also need a wire that can handle the fuse rating plus a good bit of safety factor. Use O or OO for the home run, and the largest possible for the short hookup to the engine. O gauge is rated at 285 amps DC and would have about 5% drop at 90 amps.

Here's a table from Mercury that agrees with this - http://www.bestboatwire.com/media/catalog/product/pdf/Engine-Size-Wire-Gauge-Table.pdf

Okay, dug up an OMC chart - http://forums.iboats.com/filedata/fetch?id=7014081

Note that OMC specifies a maximum of 20' run regardless of cable size.

 

Maybe I just move house battery forth then relocate the start battery to cuddys dry storeage just in front of helm
this would reduce the 17' extension to 11' will the dry storeage box have to be vented.

will the extra bounceing slamming bow ruin the house battery?

edit I have plastic battery boxs for both batterys. also have 0AWG tinned cable


attach image of the way I was planning to connect the batterys.


Thanks for the tips TB

 

update I extended the engine power line ten feet ,connected the positive wire from engine to the middle position on my battery isolator out of isoltaor B1 to positive of start battery then extended negitive from engine to neg of start battery result no power to engine,
by passed isolator got power to engine, have only trimmed so far.

starting to think I received a none working isolator from e bay can it be tested to see if it functions? I will use a small metal brush to clean the isolators terminal

temporarily installed battery kill/off switch need to attach to hull.

 

You should consider the common problem of adding so much shtuff on a small boat it becomes sluggish and very unstable.
You might consider carbon monoxide getting sucked into your cabin from your outboard or a generator if you plan on one.
If 'forth' means into your cabin, you might want to reconsider putting your batteries in there because of the harmful/deadly/explosive fumes they can give off.
What hazardous gases are associated with lead acid battery charging stations? | GfG Instrumentation | GfG Instrumentation http://goodforgas.com/hazardous-gases-associated-lead-acid-battery-charging-stations/

 

are these fumes created only when charging?

the vessel has a person/gear capsity of 2950LBs batterys weight like 30LBs each.

yes I have a generater that will be located on dive plateform.

I do plan a carbon monoxide detecter when I start w. the generater.

is there a battery fume detecter?

what do you think about my isolator?
Thanks TB

 

Well, I'm not sure about fumes when not charging, but whenever you run your boat you're charging the batteries.
I've read where people have died from carbon monoxide hanging off the swim platform while motoring, not that that has anything to do with your boat, just FYI.
How will you keep the generator dry on the swim platform?
It would suck having survived deadly fumes only to be electrocuted on the swim platform or back deck.

 

No idea about the isolator.

 

so it's not a good idea to stow batteries inside cabin I'll move back to outside of cabin.

I will first have to finish the dive plateform then fab a box to fit the generater in.

I recentely( before major storms) purchased a new tow vehical Saab SUV thats located in Jacksonville, FL near the Arlington area and st.Johns river. it's actualley been waiting for a delivery truck to pick it up for me.

now I'm thinking this vehical is ruined by flood waters. attach image of the vehical location

 

You might be ok with the vehicle. Looking at Jacksonville maps, that spot isn't in an official flood zone or even an evacuation zone. Of course it depends on the actual spot. We're not in a flood zone but the county is so incompetent in designing ditches and placing correct size culverts and so feeble at maintaining them that we had water axle deep where I keep one of my trucks. I imagine Jacksonville might be better at that stuff.