[C320-list] Fridge Usage

[Stephen Cox]

> I have still have the problem of lack of power.  We went 16 
> hoiurs last weekend and then there was insufficient power to 
> start the fridge.  Bear in ming that we have 2 x 150A house 
> batteries and a separate starting battery.
> The general comments indicated that we should be okay for 48 
> hours, as all three batteries indicated being fully charged 
> when we left the marina If anyone can shed some light on this 
> I would be grateful.


Colin,

How did the batteries indicate being fully charged?  If you only have the
analogue voltage meter on your control panel as a guide then your estimate
of state of charge may well be somewhat out.  I know on my C320 that the
analogue meter doesn't agree all that well with the digital power monitoring
meter I installed.  The analogue is often quite optimistic about the voltage
on the batteries. 

In any case, showing 13.6v doesn't necessarily mean they are fully charged.
The first 80% is relatively easy to achieve but the last 20% takes a
disproportionate amount of charging time.  Is your (presumably) mains
charger set to charge to 13.6v or 14.2 or 14.4v?  Fully charging with a
13.6v setting takes a long time.  

What was the voltage when the fridge wouldn't start?  Did you have other
things on at the same time?  The AM/FM radio takes an amp or two, the VHF
radio takes an amp or two on standby, the instruments take one or more amps,
were you using an autopilot cause they consume power too and the fridge is
likely pulling five amps or more.  Was the freshwater system or bilge pump
cycling?  It all adds up.

Just some thoughts,

Stephen Cox
Tegwen #1141
Canberra AUSTRALIA