[C320-list] Battery Charger Wire Size

[Welch, Myron D]

Karl,

Thanks for the link to the Blue Seas site which has a lot of useful information. I do use one ring per MRBF, but what I found interesting on their "caution" page was the fiber washer. My terminal blocks did not come with them and I have contacted Blue Seas for replacements. 

Myron

Sent from my iPad

On Aug 12, 2012, at 8:32 PM, "Karl Mielenhausen" <kmielen at suddenlink.net> wrote:

> Remember the cautions when using the MRBF as shown in this document...
> http://bluesea.com/viewresource/640
> ONLY ONE ring terminal allowed per fuse. That's why you will need more
> then one. Of course that allows you the option to fine-tune the fuse
> sizes.
> 
> Karl
> 
> On Sun, Aug 12, 2012 at 7:36 PM, Welch, Myron D <myron-welch at uiowa.edu> wrote:
>> Karl,
>> 
>> Thanks for the suggestions. The MRBF terminal fuses started out as a way to finally fuse my charger, something that has been on my "list" for several years. As I make the changes and upgrades to install the start battery, I am putting them on the alternator to house battery wire, both battery connections from the ACR, and other places I find that need protection. Yes, our factory wiring does seem incomplete. I'm pleased that so many on this list are available to help.
>> 
>> Myron
>> 
>> Sent from my iPad
>> 
>> On Aug 12, 2012, at 7:16 PM, "Karl Mielenhausen" <kmielen at suddenlink.net> wrote:
>> 
>>> Each lead from my Xantrex charger is fused at the battery end with a
>>> 20A Gould TRM20 inline fuse. According to the literature, they have a
>>> 200% rating time delay of 12 seconds.
>>> That seems appropriate as the wire should only see the max output of
>>> the charger TO the batteries, 20A. If the charger fails and somehow
>>> creates a dead short, the 20A fuse will eventually open under the
>>> massive current flowing FROM the batteries.Hopefully before the fire
>>> starts.
>>> 
>>> I assume your installation of the MRBF (Marine Rated Battery Fuse)
>>> Terminal Fuse is to provide circuit protection for the entire DC
>>> system, not just the battery. I am planning to do the same as this
>>> seems to be a weakness in our installations as well as most boats.
>>> Since you are protecting the entire DC side from excessive current
>>> flow, you will need to estimate the max DC load coming from the
>>> batteries under normal conditions (is it at starting?) and figure out
>>> how long that load will exist (ie. can I use a fuse with some
>>> time-delay characteristics?).
>>> I looked at this some time ago and concluded that I would need a 150A
>>> fuse to avoid tripping with the starting current on top of the other
>>> loads at the time of starting. Anyone else looked into this and have a
>>> different answer?
>>> 
>>> Karl
>>> 
>>> On Sun, Aug 12, 2012 at 1:25 PM, JJ Morrison <sail-ability at sympatico.ca> wrote:
>>>> 
>>>> I have used 4AWG on my Zantrex True Charge 2 and at 40amp I fused it to 50amp which is what the Zantrex folks advise. I also used the MBTF fuses which makes a really neat job; no requirement to cut wire.
>>>> Cheers
>>>> JohnM
>>>> 
>>>> 
>>>> 
>>>>> Date: Sun, 12 Aug 2012 07:10:52 -0400
>>>>> From: kmielen at suddenlink.net
>>>>> To: C320-List at catalina320.com
>>>>> Subject: Re: [C320-list] Battery Charger Wire Size
>>>>> 
>>>>> 4 AWG wire on my 2000 model. Not sure on fuse size... why not 20A if
>>>>> that is the max output of your charger?
>>>>> 
>>>>> Karl
>>>>> 
>>>>> 
>>>>> On Sun, Aug 12, 2012 at 12:01 AM, Dick Walker <dickwalker at att.net> wrote:
>>>>>> I suggest you put the start battery on #1 and the two batteries on #2. Easy to remember.
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> Cheers
>>>>>> 
>>>>>> Dick Walker
>>>>>> 
>>>>>> 
>>>>>> On Aug 11, 2012, at 8:36 PM, "Welch, Myron D" <myron-welch at uiowa.edu> wrote:
>>>>>> 
>>>>>>> I am about to begin installation of a dedicated start battery and parallel my two 4Ds as the house battery.
>>>>>>> 
>>>>>>> I will be changing and installing several new cables and have a question about the wire running from the charger to the house battery. I have a 1995 model with a Xantrex 20 amp charger mounted on the forward bulkhead of the port locker. It has a #10 wires to the battery which I believe is considerably undersized. I believe Catalina changed this wire size on later models. For those of you with newer boats, what size wire is used?
>>>>>>> 
>>>>>>> Also, there were no fuses from the charger to the battery. I have now added MRBF fuses. What size fuse should I use?
>>>>>>> 
>>>>>>> Thanks for your help.
>>>>>>> 
>>>>>>> Myron Welch
>>>>>>> Wind Instrument, #238
>>>>>>> Iowa City, Iowa
>>>>>>> Edward C. Grace Memorial Harbor
>>>>>>> Elk Rapids, Michigan
>>>>>>> 
>>>>>>> Sent from my iPad
>>>>>>> 
>>>>