[C320-list] DC power system upgrade advice

[warren updike]

Gary, that's a lot to swallow. A lot depends on how you use the boat.  We
are cruisers and like to anchor or moor so quick recharging and days at
anchor with refer, TV, lights, etc. are important.  We are also retired and
go for several 2 and 3 week trips each year.

Perkins alt.: It is a Lucas A127, rated at 55A. However, under actual
conditions, once the alt. heats up in the engine compartment you're lucky to
get 35A from it.  You don't actually say you are thinking about upgrading
the alt.; but, if you do, it is not a simple project on the Perkins M30.  I
say that because the Lucas mount is, apparently, not US automotive std. I
used an AmpTech small body alt. and had to modify the engine block bracket
as well as make a new slotted adjusting arm. Lots of machining, welding,
griding, many dry fits.  Not trivial, but still worth doing esp. if you are
spending the boat units on new batteries either gel or AGM. I also installed
an external regulator and battery monitor.  I think you'd find the effort
similar even with a Balmer Alt.  

Were I to do it again, I'd select the smallest alternator that would give me
80A. The reason being that on the Perkins, the belt is 3/8" and the max.
recommended output is 80A. The Yanmars, I believe, have a 1/2" belt and so
can go to 120A. I found no cost effective way to retrofit the Perkins with a
1/2" belt for the alt.

Ext. Alt: If you go to Gel batteries, you will definitely need an external
regulator. This would require installing a field wire on the Alt. (it
doesn't have one as it is internally regulated.)  You need a smart reg. that
can be configured for various battery types or you can risk overcharging
Gels. With too small an output and not much engine time, you risk
undercharging the bank, also a bad condition. Most marine alternators will
support an ext. reg. without alteration. 

Re. Shore Charger: A 20A charger will bring your bank up if it is on
overnight (9-10 hours.)  A 40A will only do it faster. With Gel batteries,
same deal, the charger needs to be smart and configurable. AGMs charge like
wet cells only faster, still need smart charger. With Gels or AGM it is
recommended that you have the optional batt. Temp sensor installed.

Re. batteries: If you parallel your 2, 4Ds, as most recommend you do (there
are compelling reasons,) then you should have a sep. starting bank or at
least a jump starter thing. When you have a separate start bank, the dash
board runs from that bank: glow plugs, blower, gages. Without the separate
start band, that power comes from your house bank. Of course, that load is
well covered by the alternator; but, it's that much less going to charge the
bank.

If you have a separate start bank, paralled 4Ds (300-400AH,) never pull them
down more than 50%, can get them recharged fully when needed, leave them
fully charged when not in use,  then the least expensive option may be good
old lead/antimony wet-cell batteries.  AGMs will recharge faster, and give
more cycles; but, at twice the cost.

I went with Interstate SRM-4D batteries, 390RC(minutes,) that translates
into about 200AH each. These are not the std. commercial 4Ds as they have a
higher capacity and have heaver plates. 

I use about 80-100AH a day in the Summer, and can recharge them fully with
about 1.5 or so hours of running engine.

I'm also replacing interior lights with LEDs. When the mast next comes down,
I'll replace anchor light with LED. 

We also use a 10lb block of ice in bottom of the refer. It's amazing how
that helps. The block from our 2-week Spring trip in May went with us for 2
more weeks in June, and we still threw out about 2lb of it. We also cover
our refer with unused closed cell cockpit cushions between meals. That helps
a lot as well.

I have a bunch of pictures from my DC upgrade. Send me an address, and I'll
send them to you. (Ours is a Perkins M30. I'm not sure if my experience
translates to a Yanmar. See Jeff Hare photos in the Gallery on the web
site.)

Warren & Pattie Updike
Catalina 320, #62, "Warr De Mar"
Middle River, Chesapeake Bay





-----Original Message-----
Hull 205--- I need to replace the 4D batteries, and am not sure if I should
stay with the flooded or go to the Gel cells.  My 30 amp Newmar charger is
humming a 60hz tone that pier walkers can hear, which started this project.
I think I understand the pros and cons of both types of battery and I think
that a new 40A  Xantrex charger will handle either while at the slip. I have
the Perkins engine with the original alternator. If I choose the gel
technology now, and buy the new charger, do I also need to buy an external
regulator? Does anyone know the output specs of the OEM alternator? Any
danger of the OEM alternator damaging the gel cells? Option 2 is to stay
with the wet cells, and the Xantrex charger and keep the internally
regulated OEM alternator. (KISS)   

I did buy the reference book suggested earlier, but it seems to give me a
lot of choices, that can become expensive and complicated. 
Normal use is shore power most of the time with two or three day trips
sailing the Apostle Islands.  We are planning a two week trip to the Lake
Superior North shore, and I am concerned with the charge rate of the
batteries if we don't spend a lot of time under power. I have considered
paralleling the two new batteries, and taking along a deep cycle battery
with jumper cables as an emergency back up just for the duration of the
trip. 

  
Gary Magnuson
Time-A-Weigh #205