"Nigel" wrote in
:

I have a 24v electrical set up on my boat, but need a 12v supply for
my VHF (amongst other things). Is there any reason why I can't just
run a 12v supply from just one of a pair of batteries, or do I need to
use a 24v/12v converter. I release this will draw charge from just one
battery , but won't the other just top it up and there by drain them
both equally Thanks



How about a nice switching (99% efficient) converter, instead of some
jackleg series regulator draining power off the 24V system as lots of heat?

http://www.samlexamerica.com/product...yID=5&packaget
ype=1&title=Stand%20Alone%20DC%20Power%20Converter

Figure 10A of each VHF radio and SMALL radar, Add up all the instruction
book 12V amperages, then buy the next higher model.

This is but one company producing what you need. Search Google for "24VDC
to 12VDC converter" with the quotation marks so it doesn't find every
converter on the planet. You'll get a whole list of them.

This guy's SD-350B-12 at 350W output generates 27A at 12V regulated solid
as a rock from ANY dc input voltage between 19 and 36V.....saving the 12V
electronics from any nasty spikes on your 24V system....$215? Who's gonna
believe that when a 10A battery charger at Waste Marine is double that!!

2:1 input range
1500VAC I/O isolation
100% full load burn-in test
Short circuit protection
Over load/voltage protection
Over temperature protection
Forced air cooling by built-in DC fan
Low cost, high reliability
2 year warranty

Looks like you'd play hell trying to destroy it, too!