"mack" wrote in
:

The boat supply is 12 volts DC - but when charging i.e engine running,
this can rise to above 14 volts, this would no do an LCD T/V a lot of
good. T/V takes less that 5 amps DC - hope this makes my request a bit
clearer. I wish to build not buy.


Makes no difference, whatsoever, unless some idiot switches the battery
switch to OFF with the CHARGER OR ENGINE RUNNING!

The 12V input to ANY LCD TV or other electronic device made in the last
30 years is a voltage regulator or DC to DC converter that converts
whatever crap you feed it to what the TV needs, regulated to rock stable
voltage no matter what the input does from 10-20 volts, easy.

This oh-we-gotta-have-a-rock-steady-power-source nonsense comes from the
Rock-Steady Power Supply Company, LLC., who's gotta sell this crap to
stay in business. The worst stupidity is small computers, who have
switching power supplies that really don't care what you feed them, as
long as it's over about 80VAC. The computer, first, rectifies whatever
AC, pulses, spikes, buzzes, sparks, even DC fed to it and charges a few
filter caps in parallel to whatever HVDC it can get, then feeds the DC to
a highly regulated DC-DC switching regulator that turns that into highly
filtered, perfect DC that varies not over a huge range of input garbage
and load current. (I don't care if my UPS is a square wave, as long as it
runs to keep that input coming when the power company fails.)

Lionheart has a massive LCD TV made by some unknown, no-name Korean
manufacturer running straight off the house battery panel. I'm sucking
DC from the starboard DC lighting circuitry, which just happened to have
wires hanging out where we took the light down and put the TV on a swing
arm mount so we can use it for a big video monitor for The Cap'n off the
laptop. It has worked fine for many years....(c; The dock has cable!

Still not convinced? Plug the wall brick into any AC outlet and measure
the 12VDC output of it. What? You say it's over 16V open circuit! WOW!

Larry
--
Extremely intelligent life exists that is so smart they never called
Earth.