Sorry Larry you are only half right on that one. While you are correct that
a properly installed and adjusted charging system will never see anything
higher than 15V many things go schitzo when they see more than 13.5 to 14V.
Even 12V nominal halogen bulbs will loose much of their expected life if run
at battery charging voltages. Some "smart" regulators even have a "halogen
protection" setting that limit charging voltage expressly for that purpose.

The solution for sensitive electronics is a DC/DC converter. I have
installed three on Rutu. One supplies the halogen navigation lights, one is
set to 13.2 for the radios and the third also set to 13.2V is available for
what ever else needs regulated power. Unlike normal voltage regulators that
control voltage by generating heat DC/DC converters, while not perfect, are
far more efficient.

The down side is that the cheap ones can put out harmonics that show up on
HF and SSB bands so they need to be well shielded and have ferrites on all
leads.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"Larry" wrote

Totally unnecessary. Any voltage from 10-18VDC will run any electronics
made for boats.

If you want to make it smoother, take all the connections apart, wire
brush them to a nice shine then put them all back together and spray
some battery post protector on them.

What you're talking about is a voltage regulator. The only problem is
you'd have to have a much higher voltage to start out with than a
standard battery. The regulators need "overhead" voltage, unless
there's some kind of switching power supply, which I do NOT recommend
because switchers make a lot of RF noise to tear up your VHF and SSB
radios!

The battery is a natural regulator and holds its voltage quite steady at
the posts. The voltage drops you see are caused by light wiring,
corroded breakers, corroded contacts and wires.

by the way....to find where a corroded contact is is quite easy with a
simple voltmeter. Load the circuit to full load. Put the meter ACROSS
each connection and breaker. If the connection is perfect, you read no
voltage. A corroded connector has a voltage drop you can measure UNDER
LOAD CURRENT....narrows down where it is.