Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 18-06-2009, 13:19   #1
Registered User

Join Date: Apr 2007
Location: house-North Vancouver BC boat-barra de navidad
Boat: c&c landfall 43
Posts: 120
When to Charge

at what voltage should you start charging? for some reason I remember on a charter I did in BVI they told me to charge the batteries when the monitor said 10.5V but I have read here that at 12.0V is when charging should start. Can anyone shed any light on this for me. what would be a safe voltage to start charging? cheers limmer
__________________

__________________
limmer is offline   Reply With Quote
Old 18-06-2009, 14:09   #2
Senior Cruiser
 
Cheechako's Avatar

Cruisers Forum Supporter

Join Date: Aug 2006
Location: Skagit City, WA
Posts: 19,371
hmmm.... I cant remember state of charge but 10.5 is pretty much completely dead and gone! 12v sounds pretty close, however on most boats, my experience has been it's hard to stay up to 12v overnight. Isnt 11.5v 50% discharge...?
__________________

__________________
Cheechako is offline   Reply With Quote
Old 18-06-2009, 14:24   #3
Registered User
 
Sailabel's Avatar

Join Date: May 2006
Location: Home Base: Seattle; Currently Cruising in Mexico
Boat: Tayana 37- Victoria Rose
Posts: 151
Hi Limmer- the key for battery longevity is to not let the battery bank become less than 50% discharged. 10.5 volts is discharged.... I'm sure that someone will chime in soon with the voltage for 50% discharge.

You may want to consider eventually installing a battery bank monitor that will let you know when the batteries are 50% discharged... ours reads in amp-hours used and % capacity remaining. There are several options/manufacturers for the monitors.

For capacity and longevity, we ditched the 2-bank house system and wired for one large battery bank, plus a separate/isolated starting battery. This allows us more amp-hour capacity for house loads while reducing the depth of discharge on house bank.

Steve
__________________
Steve Abel
SV Victoria Rose, Tayana 37
www.sailvictoriarose.com
Sailabel is offline   Reply With Quote
Old 18-06-2009, 14:42   #4
Senior Cruiser
 
Cheechako's Avatar

Cruisers Forum Supporter

Join Date: Aug 2006
Location: Skagit City, WA
Posts: 19,371
It's complicated, but for Trojan Deep Cycle Gr27, at rest, it is: 12v = 25% charged, 12.3 volts = 50% charged , 12.5 volts = 70% charged.

definition of At Rest: "6 lead-acid cells in series and at Rest. “At Rest” means
that no current is moving through the cells, i.e., that
they are neither being charged or discharged.
Determining a battery’s state of charge from voltage
measurement is vague enough if current is moving
through the battery. The vagaries increase
exponentially if no current is moving through the
battery."
__________________
Cheechako is offline   Reply With Quote
Old 18-06-2009, 15:00   #5
Registered User

Join Date: Feb 2008
Location: Cruising
Boat: Jeanneau 38 Gin Fizz- Rhosyn Mor
Posts: 331
I am not too sure about other kinds but my Gel 8D's ( not AGM) are dead at 11.8V.
I deep discharge them down to 12.4 about once every couple of months, the rest of the time the solar panel keeps up with my usage and they pretty much stay at float voltage of 13.1
__________________
Rhosyn Mor is offline   Reply With Quote
Reply

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
Solar Charge Controllers Tropic1 Electrical: Batteries, Generators & Solar 40 14-10-2010 22:40
Charge liveaboards for amenities Pisces Liveaboard's Forum 6 03-02-2009 20:50
Tortola Theory, To Charge or not to Charge? alexleclainche Atlantic & the Caribbean 5 29-01-2008 17:30
trickle charge with drain gonesail Electrical: Batteries, Generators & Solar 6 19-09-2007 14:27
To Charge or Not to Charge... alexleclainche Engines and Propulsion Systems 2 12-06-2007 22:31



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 04:38.


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.