Jeff Morris wrote:
I never bought the logic, neither did my builder, who used the "long wire"
approach.

IMHO there are benefits to both approaches, but to choose one over the
other, you need to do some careful math.


Consider, for a 80 foot round trip and an 80 Amp load, you want "2" gauge wire
for a 10% loss.

I think that's a bit on the light side. Most charts only show wire run
lengths up to 60' and a medium size windlass is going to be a 100 amp
load anyway.

A 10% voltage drop is significant. Might knock other things off line,
especially any digital devices. I'd prefer to size things for a lower
voltage drop anyway, where practical.


... Being conservative, you might go to "0" gauge. That 80 feet
weighs 35 pounds. So the result is you would put a 35 pound starting battery in
the bow instead of distributing 35 pounds along the length.
And we're not
talking about all the complications of keeping an extra battery charged and
happy. The only virtue is that you now have some redundancy in a critical area.
But you also have another failure mode.

Either way you go, yo have another failure mode possible. If there is a
short somewhere along the 80' wiring run, the lack of resistance will
kill your whole battery bank really quick, and possibly leave scorch marks.


There are other issues, like how do you prevent 80 amps from going down the
charger wire if you raise the anchor when the engine is running? And if you
don't keep up with the use, how large a battery to you need to ensure you have
the juice to reset the anchor several times, the last time, of course, in the
middle of the night?

Well, how do you insure that your house bank isn't drained by resetting
the anchor in the middle of the night? How do you feel about sawing
holes in bulkheads to run two passes of #0 cable (or bigger) with
looming of course? How about running that big a load to ground and
putting back voltage spike on everything else in your 12V system?

There are plusses and minusses to both running cable and putting in a
dedicated windlass battery. IMHO Ray's case is just over the edge where
it looks like a good case for a dedicated windlass battery.

Fresh Breezes- Doug King