Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 30-03-2012, 12:16   #1
Registered User
 
callistov42's Avatar

Join Date: Jan 2011
Location: Seabrook, Texas
Boat: Vagabond 42
Posts: 169
AGM " Shelf Life "

I have had a group 27 AGM battery onboard for about two years that has never been in service. It has been charged two or three times over that period of time. I now need to put it into service as an isolated starting battery. Can I expect a normal 4 to 5 year life span from this point forward or has some of the battery's life passed.
__________________
callistov42 is offline   Reply With Quote
Old 04-04-2012, 14:43   #2
Registered User

Join Date: Jan 2005
Location: Seattle area (Bremerton)
Boat: C&C Landfall 39 center cockpit "Anahita"
Posts: 1,076
Images: 6
Re: AGM " Shelf Life "

High quality AGM batteries have a very low self-discharge and can stand for years (like 5) at relatively low temperatures (below 65 deg F). Test your battery internal resistance at a heavy load (about 50-75A noting that the terminal voltage drops then settles out to a constant value for several seconds before dropping again if the test runs too long). Remove the load and observe the voltage rise. The resistance is the change in voltage (from load to no-load) divided by the load current.

For a group 27 the internal resistance should be about 12 milli-Ohms. If the battery charge accepts a good current after the test (apply more thasn 14.4 V and note that the acceptance current is at least 20 A) then the battery is good and you should get 5 more years as long as you keep it on a good float voltage (13.9V) when using shore power.
__________________
"I don't think there'll be a return journey Mr. Frodo". Samwise Gamgee
Rick is offline   Reply With Quote
Old 04-04-2012, 14:57   #3
Registered User
 
deckofficer's Avatar

Join Date: Feb 2011
Location: Northern and Southern California
Boat: too many
Posts: 4,198
Images: 4
Re: AGM " Shelf Life "

I couldn't have answered any better than Rick. I am a fan of AGM and came to this thread to offer advise but with Rick's reply, none needed from me.
__________________
Bob
USCG Unlimited Tonnage Open Ocean (CMA)
http://tbuckets.lefora.com/
deckofficer is offline   Reply With Quote
Reply

Tags
agm

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Givens Life Rafts Filed for Bankruptcy chrisjs Health, Safety & Related Gear 45 16-12-2013 17:43
Life Raft Self-Service belizesailor Health, Safety & Related Gear 138 23-04-2013 17:27
Life Is What You Make Of It ;) NoDogue Meets & Greets 15 13-12-2012 02:53
Life Rafts Streets1234 Auxiliary Equipment & Dinghy 16 10-04-2012 08:55
AGM " Shelf Life " callistov42 Electrical: Batteries, Generators & Solar 2 04-04-2012 14:57



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 09:48.


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.