[C320-list] Replacement battery charger

[Dick Walker]

See My Comments Below 

A great electrical set up is described on the C320 web site,

Electrical set up is a bit like a religion you will find many solutions.



Dick Walker
WindWalker II
C-320  #687 Yesr 2000 Model
Coronado YC, CA
619.435.8986



-----Original Message-----
From: C320-list [mailto:c320-list-bounces at lists.catalina320.com] On Behalf
Of Graeme Clark
Sent: Wednesday, January 14, 2015 10:09 AM
To: c320-list at lists.catalina320.com
Subject: [C320-list] Replacement battery charger

Hi all,

A few months ago I bought a C320, hull #366, as sole owner, having
previously owned a one third share in another (#303)

I have what i guess is the "standard' arrangement of the time (1996) namely
two batteries, each 180Ah and a 1-Both-2-off rotary switch with a Fly-Tec
20-3 mains powered charger.

The previous owner never went near shore power (well almost never) so when
we connected everything and looked at voltages, I noticed that the charger
is "unwell". It delivers 15.8V to the batteries which is way too much. I
think the charging regime from the Fly-Tec is supposed to give about 14.8v
initially then reducing to a lower voltage and eventually even a lower float
charge.

So - a replacement is needed. No big deal EXCEPT that technology has moved
on a lot in the intervening 20-or-so years since the Fly-Tec was state of
the art, and therefore my questions are:

1) is a 20 Amp charger still what's needed. More Amps = more $, so maybe a
modern charger will do the same job on lower amps. Or maybe I need more
Amps?
I would get the Xantrex TrueCharge2 40 Amp Charger, 40A Capacity, 12V.  You
may want to get a Honda generator and the 40 amp would be good.  I have had
the previous Xantrex model for 15 years and it has operated fine.


2)  Should I be charging both batteries together, or one at a time. If one
at a time would a VSR (Voltage Sensing Relay) be a good idea so that one
battery gets charged before the other (I suspect not because surely the
output voltage of the charger will trigger the relay, no matter how flat the
battery, and both will end up being charged together anyway)
[Dick Walker] 

I would set up the system as follows.

ON Battery 1 on the selector have the Group 27 Starting Battery
On Group 2 have to AGM Batteries in parallel. 
Use a  CHARLES MARINE Marine Multi-Battery Isolator to separate the charge
between group 1 and 2.




3) On my old (shared) C320 the set up - rightly or wrongly - was that the
engine alternator charged only battery 1 and the shore charger only battery
2 and if you wanted to cross charge you needed to set rotary switch to
'Both'. Is this normal? Advantages and disadvantages of this arrangement?
[Dick Walker] 
See above.  This is a poor set up,  You should not need to manually change
the selector.

4) being in Britain we don't have need for AC and only a slight need for
refrigeration but our boat is not kept where it can be left permanently
plugged in to shore power and so  we plug in whenever we can get alongside
but often go for two or three days using battery only. There's normally some
motoring to help keep the batteries topped up and we have an advanced smart
charging system via the alternator but its probably accurate to say that the
battery will rarely reach full charge through motoring alone. I am aware
that battery life is extended by keeping the battery fully charged and not
left in a state of discharge for  extended periods of time, so a smart mains
charger that fully charges the batteries as fast as is practical would seem
to be sensible. Thoughts on that?
[Dick Walker] 
I keep the shore power on when we are not underway.  In addition I usually
shut off all except the bilge pump.

Many thanks and here's to great sailing for everyone in 2015

Graeme