Many marine electronic pieces are rated for 8-48 volts, having
internal regulators to extract the power they require. Many boats are
24 or 32 volts to match the requirements of the engines in them. A
friend had a Hatteras 56 FBMY with twin 8V92TA DD diesels in them. I
called them "Train Engines" because everything was 32VDC.

He like to had a heart attack when we had to replace the bad battery
banks (3 banks of 4 batteries each, each battery 4 cells (8VDC) in
series to get 32VDC per bank) Each 4-cell battery was $300! You do
the math.....(c;

Inside the Hatteras' main helm was a couple of BIG 32V to 12V analog
regulators that very inefficiently reduced 32 to 12 at great heat for
the 12V Only instrumentation and accessories at the helm and on the
flybridge above. Power isn't much of an issue when twin V-8 diesels
are chugging away at 2200 RPM in the bilge.

Your assumption about 24V using half the current of 12V is correct. I
think 12V cars was as big a mistake as 6V cars were. We should have
converted the whole damned country to 24 or even 48VDC when we had the
chance, saving millions of pounds of copper in the process.



On 18 Dec 2003 01:34:19 -0800, (PeterV) wrote:

I've checked through the archives and found a few on this subject but
none that clearly state if there is any real advantage of running a
24V system.

Obviously the current draw for a given load will be less but I've
not seen any mention of 'standard' instruments that run on 24V. I've
read somewhere that fishing trawlers use higher voltage systems
(24/36V?) but do they have DC-DC conversion (36-12V) for their
instruments? Or do they use 24/36V instrumentation? I assume, as 12V
is 'standard', that costs of higher voltage instruments will be more
expensive than 12V ones.


Thanks,

Peter

Larry W4CSC

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