[C320-list] Alternator to batteries

[Utility Email]

Scott,

I concur with Warren stated.  

I installed battery cable fusing as a safety measure.  I recall seeing some ABYC references on this and decided to do that to protect shorting of these high current cables.  In fact, I did both battery cables and the charger cables.  This is how the OEM cables were set up in my 2007 C320 MK II.  Rather than spend time to look up ABYC standards, see the Compass Marine site on this topic.  I find this information helpful and therefore followed that advice for safety reasons.  I used Blue Seas Systems ANL fuses.  See the article at the site below:

http://www.pbase.com/mainecruising/battery_fusing

Dave Swanson
S/V Emily Ann
2007 C320 MK II, No. 1107
Mukilteo, Washington


David B. Swanson, P.E., S.E.
Principal, LEED AP, F. SEI
Director, Structural Engineering

Reid Middleton, Inc.
(425) 741-3800 office
(425) 741-5011 direct
(425) 508-7971 mobile

www.reidmiddleton.com

Washington | California | Hawaii | Alaska


> On Mar 27, 2017, at 6:03 AM, Scott Thompson <surprise at thompson87.com> wrote:
> 
> The question is about the connection from the alternator to batteries. The shore power charger connection is different.
> 
> (BTW, if the shore power charger cable fuse is sized to the cable then there should be no need to up-size the fuse unless you also up-size the cable!)
> 
> Again, if there is an ABYC requirement to fuse the battery to engine circuit I'd like to see details. I haven't been able to find any such thing online. (Which does not mean its a bad idea.)
> 
> 
>> On 3/27/2017 8:13 AM, Warren Updike wrote:
>> Ahhh, someone I know rather well changed the shore charger from 20 to 40A and didn't know to increase the amperage of the fuses on the battery cables. That nearly crashed a cruise.
>> 
>> Battery fuses are now required/suggested by ABYC. Their purpose is not to protect equipment but to prevent melting cables in case of a direct short. These fuses are sized to the ampacity of the cable not necessarily the maximum load potential. Or so I'm given to understand.
>> 
>> Warren and Pattie Updike
>> 1994 C320 "Warr de Mar" #62
>> Middle River, Chesapeake Bay
>> 
>> -----Original Message-----
>> From: B. Stumpp [mailto:bstumpp at comcast.net]
>> Sent: Sunday, March 26, 2017 3:28 PM
>> To: c320-list at lists.catalina320.com; tharrison at innovations-plus.com
>> Subject: [C320-list] Alternator to batteries
>> 
>> Ted,
>> 
>>  
>> Reach under the settee where your batteries are and feel for an inline fuse
>> in your positive (and negative?) cables a few inches from the terminals.
>> 
>> One or all of these fuses are probably blown and need to be replaced.
>> 
>> I've never seen inline fuses in battery cables fuses before, Catalina must
>> put them there for some sort of boat manufacturer regulation.
>> 
>> Finding the fuses there is a surprise to a lot of people.
>> 
>> I ran into the same problem a few years ago and couldn't figure out why my
>> batteries were going bad when in fact they just were not charging.
>> 
>> Found the problem by disconnecting both ends of the cables and doing a
>> continuity test.
>> 
>> Never understood why/how I blew these fuses but people have surmised it may
>> have something to do with plugging into shore power.
>> 
>>  
>> Bruce Stumpp
>> 
>> #647, Adventure
>> 
>> Frog Mortar Creek, Maryland
>> 
>>  
>> Message: 8
>> 
>> Date: Sat, 25 Mar 2017 11:53:23 -0400
>> 
>> From: Ted Harrison <tharrison at innovations-plus.com>
>> 
>> To: C320-List at Catalina320.com
>> 
>> Subject: Re: [C320-list] Alternator to batteries
>> 
>> Message-ID:
>> 
>>                 <132D5517-84A0-4668-A8D3-DE38DAA7F042 at innovations-plus.com>
>> 
>> Content-Type: text/plain;            charset=utf-8
>> 
>>  
>> I will get back to you on this one. Will go to the boat (on the hard) next
>> weekend
>> 
>>  
>> Thanks for your help.
>> 
>>  
>> Ted Harrison
>> 
>>  
>> 
>