Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 14-09-2008, 20:47   #1
Registered User

Join Date: Mar 2008
Location: The Sea
Boat: Coronado 30 - Lady Eliza
Posts: 241
Images: 11
Test battery life

I was given two "nice looking" 100amp hour enclosed (no water filling) batteries that are alledged to be "only a couple years old and still good". How can I test to see what kind of life expectancy they have left?
__________________

__________________
"It is never too late to be who you might have been." -George Eliot
Jack Long is offline   Reply With Quote
Old 14-09-2008, 21:51   #2
Moderator Emeritus
 
David M's Avatar

Cruisers Forum Supporter

Join Date: Sep 2007
Location: San Francisco Bay
Boat: research vessel
Posts: 10,150
Jack,
You can use a battery tester similar to this one. Auto supply stores sell them or perhaps you can find someone who will loan you one?




http://www.northerntool.com/webapp/w...3303_200323303
__________________

__________________
David

Life begins where land ends.
David M is offline   Reply With Quote
Old 14-09-2008, 22:01   #3
Registered User

Join Date: Mar 2008
Location: The Sea
Boat: Coronado 30 - Lady Eliza
Posts: 241
Images: 11
I could probably just lug them in...

So that will give me a sense of how many deep cycles are left? The picture doesn't get big enough to tell what those readings indicate.

Thank you!
__________________
"It is never too late to be who you might have been." -George Eliot
Jack Long is offline   Reply With Quote
Old 14-09-2008, 22:11   #4
Moderator Emeritus
 
David M's Avatar

Cruisers Forum Supporter

Join Date: Sep 2007
Location: San Francisco Bay
Boat: research vessel
Posts: 10,150
Battery testers tell you how much of a charge a battery can hold. I don't know if your batteries are deep cycle batteries or not. I don't think that testers can measure how many cycles are left because batteries basically go from good to bad gradually meaning they hold less of a charge with each deep cycle in addition to losing their ability to hold a charge over time.

I was just thinking that if you hauled them into a car repair garage that they could put your batteries on their tester and tell you...and not charge you an arm and a leg. You will though need to charge them up overnight on a slow charge beforehand.
__________________
David

Life begins where land ends.
David M is offline   Reply With Quote
Old 15-09-2008, 08:12   #5
֍֎֍֎֍֎֍֎֍֎

Cruisers Forum Supporter

Join Date: Apr 2006
Posts: 13,022
100 amp hour, sounds like Group31 or similar. But "sealed" doesn't say much, are they gel batteries? "Sealed valve regulated" meaning "AGM" batteries? Or just "maintenance free sealed" wet acid batteries?

If they are wet acid, you might want to put an equalizing charge on them first, to recover any lost capacity. AGM and gel generally don't get equalized, but a thorough charging would be in order.

You can do some load testing right on the boat by using some simple loads and clocking them, i.e. put a standard 65-watt auto headlight on a battery, that's about a 5-amp load, see if it can run for ten hours without getting very dim compared to the other (fully charged) battery. The load tester from the auto supply store may be designed to test SLI batteries under heavy starting loads--that's still a good test, but results will vary a bit for SLI versus deep cycle draws.
__________________
hellosailor is offline   Reply With Quote
Old 15-09-2008, 09:52   #6
Registered User

Join Date: Aug 2007
Location: Florida,Colorado
Boat: Morgan OI,41ft.seadancer
Posts: 35
The battery tester shown above is not the way to test then. Not only do you need to load test them,after a proper charging,but the resistance should be measured And not with an ohm meter. A good quality tester will do both. There not cheap but you get what you pay for.
__________________
fcsob is offline   Reply With Quote
Old 15-09-2008, 09:57   #7
Marine Service Provider
 
AnchorageGuy's Avatar

Join Date: Mar 2003
Location: Wherever the boat is!
Boat: Marine Trader 34DC
Posts: 4,618
Quote:
Originally Posted by fcsob View Post
The battery tester shown above is not the way to test then. Not only do you need to load test them,after a proper charging,but the resistance should be measured And not with an ohm meter. A good quality tester will do both. There not cheap but you get what you pay for.
Well I have used that type of tester for years to give me an indication of the state of a battery with much success. But then I am experienced in using the equipment. The battery does need to be fully charged and then sit for a period of time with no load before testing. Any test equipment has certain parameters to be useful. You can take them to a battery shop and for a nominal fee they will fully charge them and test them for you. It is still less than buying the test equipment and someone more knowledgeable can give you a definitive answer.
__________________
Chesapeake Bay, ICW Hampton Roads To Key West, The Gulf Coast, The Bahamas

The Trawler Beach House
Voyages Of Sea Trek
AnchorageGuy is offline   Reply With Quote
Old 15-09-2008, 10:29   #8
Registered User
 
hanschristian38's Avatar

Join Date: Jun 2008
Location: Maine
Boat: Defever 41 "Bear Holiday"
Posts: 155
Images: 3
Send a message via Skype™ to hanschristian38
West Marine stores have a tester and will test them for you. That's how they determine if a battery is not working properly for warrantee.
__________________
hanschristian38 is offline   Reply With Quote
Old 15-09-2008, 12:51   #9
Moderator Emeritus
 
David M's Avatar

Cruisers Forum Supporter

Join Date: Sep 2007
Location: San Francisco Bay
Boat: research vessel
Posts: 10,150
Quote:
Originally Posted by fcsob View Post
The battery tester shown above is not the way to test then. Not only do you need to load test them,after a proper charging,but the resistance should be measured And not with an ohm meter. A good quality tester will do both. There not cheap but you get what you pay for.
That type of tester does load test them. There is a large resistor that heats up during the test. I agree, they do need to be load tested.
__________________
David

Life begins where land ends.
David M is offline   Reply With Quote
Old 15-09-2008, 13:48   #10
Registered User

Join Date: Aug 2007
Location: Florida,Colorado
Boat: Morgan OI,41ft.seadancer
Posts: 35
David
That tester only test @125 amp draw. You need to be able to adjust the load for different size batteries to diagnose them. The resistance is to show you if the battery can take a proper charge. We use a Snap-on MicroVat among others.
__________________
fcsob is offline   Reply With Quote
Old 15-09-2008, 16:40   #11
Moderator Emeritus
 
David M's Avatar

Cruisers Forum Supporter

Join Date: Sep 2007
Location: San Francisco Bay
Boat: research vessel
Posts: 10,150
His batteries are 100 amp-hr batteries. The tester is rated for batteries for 125 amps. Thats not good enough? What is?

He isn't testing a couple of 8-D's
__________________
David

Life begins where land ends.
David M is offline   Reply With Quote
Old 15-09-2008, 16:52   #12
Marine Service Provider
 
AnchorageGuy's Avatar

Join Date: Mar 2003
Location: Wherever the boat is!
Boat: Marine Trader 34DC
Posts: 4,618
it should not matter. The tester is designed to put a load on the battery and once the load is removed to determine the state at that point. Once you have this information you can then do further testing. If the battery bounces right back then it is probably good. The load is only applied for about 10 seconds.
__________________
Chesapeake Bay, ICW Hampton Roads To Key West, The Gulf Coast, The Bahamas

The Trawler Beach House
Voyages Of Sea Trek
AnchorageGuy is offline   Reply With Quote
Old 15-09-2008, 17:41   #13
Registered User

Join Date: Aug 2007
Location: Florida,Colorado
Boat: Morgan OI,41ft.seadancer
Posts: 35
You are only to test a battery @ half it cold cranking capacity, not amp hour capacity. You should also test it three times with a pause of aprox 20 to 30 seconds between test.
__________________

__________________
fcsob 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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Old battery, new life? SkiprJohn Electrical: Batteries, Generators & Solar 23 06-12-2007 03:27
Battery Life--Storage svHyLyte Electrical: Batteries, Generators & Solar 2 22-11-2007 13:19
test only duckie Off Topic Forum 6 06-08-2007 03:40
Battery charger to replace battery? lilly Electrical: Batteries, Generators & Solar 5 22-07-2006 19:11



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 19:17.


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.