[C320-list] Batteries

[Mark Seyler]

>From my experience, battery selection is very dependent on individual use.  I have replaced my 4Ds twice in about 7 1/2 years (once when I first bought the boat, the second time this past winter.)  Each time I went with Interstate 4Ds that cost me around $200-$225 each.  For my use they have been fine, but I mostly day-sail, and am on shore power when not sailing.

If your use is like mine, then increasing your total amp-hour capacity by upgrading to AGMs may not bring you much benefit.  If you cruise extensively, or are on a mooring without access to shore power, the higher total capacity and the ability of the AGMs to accept higher bulk charge rates (and therefore recharge faster) may be very worthwhile.  What kind of sailing do you do?  Did you run into power limitations from the old wet cell batteries?  Even if you did, you might get as much benefit out of adding a dedicated starting battery, so you could wire your 2 house batteries in parallel, and effectively double the capacity of the house bank.

As far as your alternator, the OEM alternator on my 1995 #232 is a Lucas 55 amp.  Those alternators are not designed to run at max capacity constantly, and replacing with AGMs could potentially burn it up.  Even if it survived, the alternator wouldn't be able to supply the higher bulk charge rates to take full advantage of the AGMs.  (Alternator efficiency goes down as temperature goes up, and it wouldn't even deliver 55 amps for long.)  If you have a similar alternator, consider an upgrade if you also change to AGMs.  But I think I have read posts by some owners suggesting you might have to modify the alternator mount, and/or run into space problems in the motor box.

I hope this helps some.

Mark Seyler
S/V Reality, #232


-----Original Message-----
From: C320-list [mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of Scott Westwood
Sent: Wednesday, July 11, 2018 12:15 PM
To: C320-List at Catalina320.com
Subject: Re: [C320-list] Batteries

Does bring up another question related to batteries.  If I do change to AGM:
1. Will I need to change the Alternator?2. How can I tell the existing Alternator size?  Have to assume it is original but???

 
Thanks,
Scott Westwood scottwestwood at bellsouth.net H (919)-362-8538    C (919)-618-7185

      From: John Morrison <sail-ability at sympatico.ca>
 To: C320-List at Catalina320.com 
 Sent: Wednesday, July 11, 2018 1:06 PM
 Subject: Re: [C320-list] Batteries
   
If U we’re going to the Caribbean I say go with the AGMs. One of the best characteristics of AGM is that they will accept a very high rate of charge so you should replace your alternator to a 100amp +. If you are just cruising NA and alongside most times then in my view stick with the flooded cell. 
Cheers
JEM 1999#574

Sent from my iPhone

> On Jul 11, 2018, at 7:26 AM, Scott Westwood <scottwestwood at bellsouth.net> wrote:
> 
> OK.  Another loaded question:
> I am trying to dig into the decision to replace the existing battery(ies) or switch to AGM.  One of my Liquid Batteries is toast and needs to be replaced.
> AGM batteries are more than twice the price and it will "likely" mean replacing my existing charger.  I need to verify that but I am assuming, for now, that I will need to replace the charger I just installed 3 years ago.
> I understand the value of non-liquid AGMs and not having to keep re-filling distilled water, heeling not an issue, etc....
> If I go ahead and go to AGM and replace my charger, then I might as well go ahead and get an upgraded monitoring system.  Right now I have the old analog rocker switch and I would go/add a digital one that would show the current load.  I always like the thought of knowing how much current you are drawing "right now".  I added a remote panel monitor for the charger when I replaced it so I have some sort of monitor but would be nice to know current draw.
> A co-sailor is suggesting I move to the West Marine 4D  at $790 each... while I can replace the existing liquid LA for $280 each and keep my charger.
> Does anybody have any experience with longevity of the AGMs?  If they live twice as long it might be worth it to do it all now.  If not then I don't see the value.  I can replace these LA batteries every 5+ years and save boat units.
> May even think about adding a start battery??
> Any thoughts out there?  Has anybody re-done all this and have models/pics/experices etc....  Projects on the website?
> I said it was a loaded question(s). 
> Thanks,
> Scott Westwood scottwestwood at bellsouth.net H (919)-362-8538    C (919)-618-7185