No question that a DC to DC converter completely removes the
problem. Whether it is economical depends on what "amongst
other things" Nigel wants to connect at 12 volts. FWIW,
Ample Power for one makes 24 volt chargers that are really
two independent 12 volt chargers, one across each battery.
That ensures the proper charging voltage for each.

Chuck


bowgus wrote:
If you use a DC to DC converter, then you know you will be getting a
regulated 12 Volts (or maybe 13.8 for the VHF???) ... just get one with an
appropriate power output ... i.e., no need to spend big bucks for more power
than you need. I myself would go with a converter ... that way the VHF is
guaranteed to work.

"Nigel" wrote in message
...

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