Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 14-08-2012, 20:22   #1
Registered User
 
nitpik's Avatar

Join Date: Feb 2010
Location: Canada, North Channel of Lake Huron
Boat: 41' Colvin Gaff-rigged Schooner
Posts: 222
Send a message via Yahoo to nitpik Send a message via Skype™ to nitpik
Battery Inter-Connect

When connecting a number of 6-volt batteries to form a larger house bank, is it OK to use a slightly smaller gauge wire to join the pos. and neg. terminals of two batteries connected in series?
Details:
6 Lifeline GC-4CT's, set up as three series pairs, then paralleled, to give a 660 Ah house bank.
- 30 foot return trip from batteries to DC main panel, and projected load of 70 amps to a max of 150 amps, suggests 2/0 main battery cables.

Am I wrong to think that the inter-connecting cables within the house battery would be "sharing" the load, both during charge and discharge, and so could safely be AWG #1, or 1/0 cable?
Not a big deal, but it would make wiring a little easier.
__________________

__________________
Some days you step in it ............... some days you don't.
nitpik is offline   Reply With Quote
Old 14-08-2012, 20:39   #2
Registered User
 
ExRonin's Avatar

Join Date: May 2012
Posts: 23
Nitpick
Because of both the distance (I assume the 6V batteries are in close proximity and these are short connections) and due to the way current flows) the interconnect can be a smaller gauge. A good rule of thumb is 1 gauge smaller than your main bus wires. Understand this is only for the series connections. The parallel connections need to be the same gauge as you main bus. Hope is helps.
__________________

__________________
ExRonin is offline   Reply With Quote
Old 14-08-2012, 20:40   #3
Registered User
 
sailing_jack's Avatar

Join Date: Apr 2011
Location: Eastern Ontario
Boat: Ta Chiao CT 35 Jack, CS27 Christina, Ranger 23 Strider, I14 Aggie
Posts: 79
I understand the logic, but I wouldn't do it. the conductor has to be able to carry the full load. As a rule, conductor size should only ever be reduced if there is a fuse protecting the smaller wire.
__________________
sailing_jack is offline   Reply With Quote
Old 14-08-2012, 20:42   #4
Registered User
 
sailing_jack's Avatar

Join Date: Apr 2011
Location: Eastern Ontario
Boat: Ta Chiao CT 35 Jack, CS27 Christina, Ranger 23 Strider, I14 Aggie
Posts: 79
exronin is right about the series connectors. that is a separate conductor.
__________________
sailing_jack is offline   Reply With Quote
Old 14-08-2012, 20:49   #5
Registered User
 
ExRonin's Avatar

Join Date: May 2012
Posts: 23
Thanks Sailing Jack, you saved me the trouble of a reply detailing current flow in series and parallel connected batteries. <flowers>
__________________
ExRonin is offline   Reply With Quote
Old 15-08-2012, 08:08   #6
Registered User
 
nitpik's Avatar

Join Date: Feb 2010
Location: Canada, North Channel of Lake Huron
Boat: 41' Colvin Gaff-rigged Schooner
Posts: 222
Send a message via Yahoo to nitpik Send a message via Skype™ to nitpik
Re: Battery inter-connect

Thanks guys - I thought that was the case regarding the currents flowing in the series connections, but it is always a good idea to bounce it off other sailors.
Just thought of a possible exception - future 1500W windlass installation, wired to one end of the six-battery bank. The large current draw will be coming off the "top" of all the batteries. Will the full current then be passing through those series connections?
__________________
Some days you step in it ............... some days you don't.
nitpik is offline   Reply With Quote
Old 15-08-2012, 08:45   #7
Registered User
 
ExRonin's Avatar

Join Date: May 2012
Posts: 23
Quick crude drawing. Your windlass is "just another load" and should be connected (through a breaker) to the positive and negative busses, not direct to the batteries. Note that the path of the parallel connection is important.
Attached Thumbnails
Click image for larger version

Name:	image-2961671430.jpg
Views:	76
Size:	313.6 KB
ID:	44934  
__________________
ExRonin is offline   Reply With Quote
Old 15-08-2012, 08:55   #8
Registered User

Join Date: Nov 2009
Posts: 91
Re: Battery inter-connect

Lots of good info and good reading on connecting battery banks at SmartGauge Electronics - Interconnecting multiple batteries to form one larger bank

Gordon
__________________

__________________
gmau is offline   Reply With Quote
Reply

Tags
battery

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 12:23.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.