[C320-list] Fridge Usage

[Warren Updike]

Colin, your duty cycle is about 30% (5/15,) which sounds about right for
late in the season after the heat of summer.  I surveyed mine as about 40%
in warmer weather.  I have a battery monitor and it shows a draw of about
5-1/2A when running.  So 24 hrs X 5.5A X 0.4DC = 52A  With fully charged
house bank of 300A, you should have about 150A to use.  That's at least 2
days on the hook depending on your other loads.  However, if your batteries
have been chronically undercharged and are a few years old they will not
take or hold a full charge and will run down quickly.  It's not at all
unusual to have this situation.  Battery management is a whole separate
topic.
My recommendations: 1) any boat with a fridge should have a battery monitor;
2) before spending any significant amounts, do a full power requirement
survey for your boat.  You'll find a spreadsheet and instructions for doing
this on our web site; 3) test your batteries with either a temp. compensated
hygrometer or load tester, this will give you a better picture of the status
of your batteries.
There is a wealth of information on the internet on managing batteries, and
Nigel Calder's books are almost a requirement for anyone doing their own
maintenance.
Most of what I know about boats I learned the hard way.
Warren & Pattie Updike
1994 C320 #62 "Warr De Mar"

-----Original Message-----
From: Colin Evans [mailto:twosailors at bigpond.com] 
Sent: Sunday, December 04, 2011 8:41 PM
To: 'Catalina Discussion '
Subject: [C320-list] Fridge Usage

 
 
Our fridge cycles on for four or five minute then off for about fifteen
minutes, does this seem correct.  I have the thermostat set on 2 and we run
out of enough power to run the fridge in less than 24 hours, which doesn`t
seem right as we have recently put a start battery on , so now the house
power is 300 amps.  The batteries are less than two years old so I don`t
think they are at fault, and are alway fully charged when we leave the
marina.
 
Any suggestions.
 
*************************
Regards
Colin Evans
Watermark #774
Lake Macquarie, Australia