Read the discussion entitled "Are zap stoppers really needed
on alternators?" starting about 11 Jul.

Properly constructed mobile electronics don't use
conventional voltage regulators that max at 30 some volts.
Typical 12 volt transients are discussed as 50, 60 and 270
volts. Do they charge more for mobile electronics only
because it says mobile or maritime? No. They must also design
for transients unique to 12 volts systems.

That 14V and 16V DC max rating would be voltage continuous.
You need further specs. How many transient volts can it
withstand? Is it designed to withstand load dump transients?

Don't use zener diodes. Use avalanche protection diodes
with names such as Transzorb and Transil.

"Richard C. Ferryman" wrote:
I have various electronic items on board which are rated at 14V and
16V DC max. I am fitting a 20" LCD TV this winter and that is rated
at 16V max. Although so far I've not had a failure I'm concerned at
spike protection and voltage regulator failure giving high voltages.
I had considered some hefty 16V zeners with suitably fused feeds to
act as protection.
Could low drop-out regulator ICs help to regulate down to a nominal
12V, but how do they work if the input voltage drops below 12V?
Any suggestions welcome. I am off in the spring on an extended trip
of around 5 years duration and am currently preparing for as many
eventualities as possible.
Richard