Battery and wiring questions
Hi,
$29 a piece is **** cheap; Would've been nice though if the West Marine guy might have suggested a little extra. Some of them are real pro's over there and boatus, some of em have never owned or dealt with more than paddles though. You allways want to go with a little extra on batteries - even with two.
Anyway, as far as cables, honestly even though it's only a 48 HP, it's still takes a bit to turn that starter. My unproffesional opinion - minimum of 4 guage battery cable, no reason to go any lower.
I'm not sure how aquainted you are with electrical stuff, but here's a little info. Pretty much the deal is that the larger the cable, within reason, the more efficiently it's going to carry the juice with. So, the end result of a little extra on battery cables is a little extra power available at the starter. You could turn that engine over with 12 guage cable, but it will require a much better charge on the battery as so much energy is lost in the trip (resistance - probably even heat with 12 guage).. so the battery may be pushing 60 amps at 12.5 volts out and the starter sees 60 amps at 11.5 volts or something.
The longer the cable run and the larger the amperage required, the more voltage loss you will see. You allways have some loss, but the idea is to minimize it - this makes it easier on the starter and battery. So.. if your batteries were up in the bow (for whatever reason).. I'd tell you a minimum of 2 guage etc. Check out a BOATUS or west marine catolog - they have a diagram showing voltage loss, with amps and distance of circuit as the variables. I'm a little picky about things, and like to shoot for 3% or less loss; shooting for 10% on the starter isn't probably a big deal.
As far as differences in cables, it's in the rating. There's a couple for automotive, which aren't bad, but aren't anywhere near as good as marine grade (ie brand name Anchor Marine Grade). Another difference is that marine grade cable is not just copper (or a mix of copper and who the **** knows what you get with cheap wire); marine grade is tinned copper - it's like galvanized steel, lasts much longer - looks silver colored. The other difference is that quality wire, (high end car stereo stuff included here) is basicly made of lots of small strands instead of thick pieces. For whatever reason, small strands transmit electricity even more efficiently; and yes, it's much more flexible and harder to break. Lastly, the sheath is better, and is probably actually waterproof.
Regular automotive wire tends to quickly corrode, even inside the middle of long passes; I'm not sure how it happens, but is probably a mix of the wire makeup itself and the sheath.
To add, any connection you make creates some resitance; to minimize that it's the same idea, use beefier connectors and tinned copper, pure copper isn't bad either, just not as good. Corrosion causes resistance. Marine grade connectors (large guage ones) have close ends - to keep the water out; marine grade shrink tube has hot glue inside to really seal out the mositure. Liquid electrical tape also helps quite a bit over the exposed metal terminals for safety and complete corrosion protection - peels right off when it's time to dissasseble too.
So.. my recomendation; it's much more expensive, but really worth it for a job done right - go marine grade everything. It will make the work of installing justified as it will perform and be trouble free for years (say a few easy, mabye 5-10). 4 guage to the switches and then to everything in the engines ciruit and give yourself some power posts along the way, for additions and accesory stuff. The first links between posts and batteries for accesories should have a good guage wire (mabye 8 in your case) and ciruit breakers ($15 - $20 for small ones, up to 50 amps or so) - then fuses in between accesories and posts etc.. go ape**** with liquid electrical tape on exposed metal, throw new good batteries into boxes (see WalMart or Auto-Zone) for additional safety/protection and you have a better than proffesional grade job in the end.
Jon
