Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 16-09-2016, 02:29   #1
Registered User

Join Date: May 2015
Location: Cruising in Greek Ionian
Boat: Hanse 445
Posts: 16
1.7V on AGM - replace?

An undocumented load killed 2x165AH victron AGMs while the the boat was unattended for 2 weeks with main power kill switch off.
The batteries charged back from 1.7V to 13.3V overnight by Victron centaur 50A charger connected to shore power.
I'm going to disconnect the batteries and check for dead cells in either of them by monitoring voltage drop while they are disconnected.
2 questions - how to check if the batteries are still good and hold the charge? And - up from such a dead low drain, is there any hope or I'd better change the batteries to be on a safe side?
__________________

__________________
SY_Maria is offline   Reply With Quote
Old 16-09-2016, 04:28   #2
Registered User
 
double u's Avatar

Join Date: Feb 2016
Posts: 331
Re: 1.7V on AGM - replace?

maybe try such a loadtester
http://images.autoserviceprofessiona...ristie-CT3.jpg
__________________

__________________
double u is offline   Reply With Quote
Old 16-09-2016, 23:40   #3
Registered User

Join Date: Jun 2013
Location: canada
Posts: 1,373
Re: 1.7V on AGM - replace?

charge them up good then do a c20 test on them. that is the best and only real way to test battery capiticy.
__________________
smac999 is online now   Reply With Quote
Old 17-09-2016, 02:48   #4
Registered User

Join Date: Feb 2015
Posts: 66
Re: 1.7V on AGM - replace?

Use the batteries as you would away from shore power, monitor voltage during discharge.

It will be obvious if they have usable capacity left or not. Either the voltage will tank under regular loads, or it will be acceptable.

Give them another 50 amp Victron recharge after the overnight load test and see if they perform any better during the next load test.

They did lose some amount of usable capacity, with such treatment, drained to 1.7v.

I'd not expect them to do well, but they might be OK for some lighter cycling, or just starting duty.
__________________
Sternwake is offline   Reply With Quote
Old 17-09-2016, 12:27   #5
Registered User

Join Date: May 2015
Location: Cruising in Greek Ionian
Boat: Hanse 445
Posts: 16
Re: 1.7V on AGM - replace?

Thank you everybody for your replies!
I fully charged the batteries using Victron AGM (up to 14.7V) charger and the put them to load - fridge, navigation and 2 chart plotters, and lights (LED) in the cabin. They lasted only 6 hours and by the end of the 6th hour they had less then 25% left in them, with 12.3V.
That's way to little compared to normal I saw before I fried them.
So replacing them with new AGMs is my number 1 option now.
Oh, well. Easy come, easy go...
__________________
SY_Maria is offline   Reply With Quote
Old 17-09-2016, 13:24   #6
Senior Cruiser

Cruisers Forum Supporter

Join Date: Jul 2005
Boat: Outbound 44
Posts: 3,534
Re: 1.7V on AGM - replace?

Where do you get less than 25% left at 12.3v? 12.3v should be considerably higher than that. Victron has that at about 1/3 discharged, ie 2/3rds charged.
__________________
Paul L
http://svjeorgia.blogspot.com
Paul L is offline   Reply With Quote
Old 17-09-2016, 14:06   #7
Moderator
 
a64pilot's Avatar

Cruisers Forum Supporter

Join Date: Oct 2013
Location: Albany Ga.
Boat: Island Packet 38
Posts: 12,745
Re: 1.7V on AGM - replace?

Can you equalize these batteries?


Sent from my iPad Pro using Cruisers Sailing Forum
__________________
a64pilot is offline   Reply With Quote
Old 18-09-2016, 00:19   #8
Registered User

Join Date: May 2015
Location: Cruising in Greek Ionian
Boat: Hanse 445
Posts: 16
Re: 1.7V on AGM - replace?

PaulL, that's what my Solara controller is showing and it is in agreement with Wurst panel. This voltage is under load so not accurate free-standing measurement. I did notice that they drained noticeably faster than before this mishap so I'll change them. I'll be doing some autonomous sailing this winter in the Med so I want to be confident in my systems for peace of mind.
__________________
SY_Maria is offline   Reply With Quote
Old 18-09-2016, 08:33   #9
Senior Cruiser
 
DeepFrz's Avatar

Cruisers Forum Supporter

Join Date: Mar 2006
Location: Winnipeg
Boat: None at this time
Posts: 7,243
Re: 1.7V on AGM - replace?

What was the current from the battery charger at the time you shut it off and began the "load test"?
__________________
The Blue Dot Campaign. This Changes Everything.
DeepFrz is offline   Reply With Quote
Old 18-09-2016, 09:52   #10
Senior Cruiser

Cruisers Forum Supporter

Join Date: Jul 2005
Boat: Outbound 44
Posts: 3,534
Re: 1.7V on AGM - replace?

Quote:
Originally Posted by SY_Maria View Post
PaulL, that's what my Solara controller is showing and it is in agreement with Wurst panel. This voltage is under load so not accurate free-standing measurement. I did notice that they drained noticeably faster than before this mishap so I'll change them. I'll be doing some autonomous sailing this winter in the Med so I want to be confident in my systems for peace of mind.
If there were no charging sources, such as solar on, then your 12.3v is not 75% discharged as you say your controllers say.
__________________
Paul L
http://svjeorgia.blogspot.com
Paul L is offline   Reply With Quote
Old 18-09-2016, 12:47   #11
Registered User

Join Date: May 2015
Location: Cruising in Greek Ionian
Boat: Hanse 445
Posts: 16
Re: 1.7V on AGM - replace?

It was none, DeepFrz. Victron charger topped these batteries to 14.7V overnight and disconnected.
__________________
SY_Maria is offline   Reply With Quote
Old 18-09-2016, 13:19   #12
Registered User

Join Date: Jun 2009
Location: Somewhere
Boat: Boatless
Posts: 1,053
Re: 1.7V on AGM - replace?

Quote:
Originally Posted by SY_Maria View Post
Thank you everybody for your replies!
I fully charged the batteries using Victron AGM (up to 14.7V) charger and the put them to load - fridge, navigation and 2 chart plotters, and lights (LED) in the cabin. They lasted only 6 hours and by the end of the 6th hour they had less then 25% left in them, with 12.3V.
That's way to little compared to normal I saw before I fried them.
So replacing them with new AGMs is my number 1 option now.
Oh, well. Easy come, easy go...
How do you onow that you "fully"charged the batteries?

Only way to be 100% sure is to keep them at the absorption voltage that ios recommended by the battery manufacturer (say 14.5V plus/minus temp comp) not until the charger decides to switch to float (which 99% of the time is too soon) but until the current going into the batteries (in amps) is equal to teh battery capacity in Ah divide by 200. This may require you to reboot teh charger to restart the absorption timer.

Cheers
C
__________________
svlamorocha is offline   Reply With Quote
Old 18-09-2016, 13:25   #13
Registered User

Join Date: May 2015
Location: Cruising in Greek Ionian
Boat: Hanse 445
Posts: 16
Re: 1.7V on AGM - replace?

How do I restart Victron? Switching it on and then off once it switched to float and then back on doesn't make it go into charge mode again
__________________
SY_Maria is offline   Reply With Quote
Old 18-09-2016, 13:57   #14
Registered User

Join Date: Feb 2015
Posts: 66
Re: 1.7V on AGM - replace?

Trick charger by loading batteries until voltage falls below 12.6v then restart charger and remove loads.

If charger sees more than 12.8v or so it assumes batteries are full and chooses float voltage, instead of seeking 14.x volts at maximum output.
__________________
Sternwake is offline   Reply With Quote
Old 18-09-2016, 14:32   #15
Moderator
 
a64pilot's Avatar

Cruisers Forum Supporter

Join Date: Oct 2013
Location: Albany Ga.
Boat: Island Packet 38
Posts: 12,745
Re: 1.7V on AGM - replace?

I know nothing of this charger, but on a programmable one, you can also trick it by making float and absorption voltage the same.
Full charge is indicated by acceptance rate in amps, on my Lifelines it .5% of AH capacity, so for my 660 AH bank it's not fully charged until at absorption voltage the amperage is 3.3 amps.
That is Lifelines, your batteries I'm sure may be different but the manual for them ought to tell you what defines a full charge, go with your batteries manual whatever it says.

I asked if these batteries and be equalized, cause if I drew my lifelines down that low, after a full charge and allowing them to cool I believe I'd equalize them to try to recover lost capacity.
Course not all AGMs can be equalized


Sent from my iPad Pro using Cruisers Sailing Forum
__________________

__________________
a64pilot 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
AGM Batteries and Battery Box Steve Kidson Electrical: Batteries, Generators & Solar 14 18-05-2010 07:30
Mixing 'types' of AGM batts?? John Drake Electrical: Batteries, Generators & Solar 18 13-12-2006 18:47
AGM and gel-cell performance notes Rick Electrical: Batteries, Generators & Solar 15 03-11-2006 20:12
AGM and gel-cell performance notes Rick Product or Service Reviews & Evaluations 1 28-10-2006 16:09
Lifeline AGM Opinions Holding Pattern Electrical: Batteries, Generators & Solar 17 20-09-2006 15:13


Our Communities

Our communities encompass many different hobbies and interests, but each one is built on friendly, intelligent membership.

» More about our Communities

Automotive Communities

Our Automotive communities encompass many different makes and models. From U.S. domestics to European Saloons.

» More about our Automotive Communities

Marine Communities

Our Marine websites focus on Cruising and Sailing Vessels, including forums and the largest cruising Wiki project on the web today.

» More about our Marine Communities


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 23:56.


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.