Charging two batteries on one charger - Page 2 - SailNet Community

   Search Sailnet:

 forums  store  


Quick Menu
Forums           
Articles          
Galleries        
Boat Reviews  
Classifieds     
Search SailNet 
Boat Search (new)

Shop the
SailNet Store
Anchor Locker
Boatbuilding & Repair
Charts
Clothing
Electrical
Electronics
Engine
Hatches and Portlights
Interior And Galley
Maintenance
Marine Electronics
Navigation
Other Items
Plumbing and Pumps
Rigging
Safety
Sailing Hardware
Trailer & Watersports
Clearance Items

Advertise Here






Go Back   SailNet Community > On Board > Gear & Maintenance > Electrical Systems
 Not a Member? 
  #11  
Old 12-04-2011
Maine Sail's Avatar
Senior Member
 
Join Date: Jan 2003
Location: Maine Coast
Posts: 5,527
Thanks: 13
Thanked 146 Times in 112 Posts
Rep Power: 15
Maine Sail is just really nice Maine Sail is just really nice Maine Sail is just really nice Maine Sail is just really nice
Quote:
Originally Posted by LakeSuperiorGeezer View Post
I always float my lead acid batteries, whether deep cycle of starter batteries when there is infrequent use. Here is a web site that explains: How Does A Float Charger Work?
If you like that and are comfortable, then it is fine, but PLEASE do check on them frequently! I have seen far to many failures of chargers, all types and brands, to leave batteries unattended and on smart of "float" chargers. I simply won't do it to my own batteries and don't and still get above average life out of them. In the cold North we simply don't need to leave them constantly plugged in if topped up and disconnected.

In hot climates it can be a necessity due to self discharge as this accelerates in warmer temps and drastically slows in cold temps..

Most all boat yards up here specifically ban this practice in the winter, if batts are left on-board, and also stipulate that the batts must be left 100% disconnected from the vessel.

Some battery manufacturers also specifically advise against it, such as Lifeline.

Not all chargers behave the same or charge the same way. Some that claim float or smart provide a constant current and some pulse it ON/OFF based on voltage. The higher the float voltage setting the more often the current will be flowing in a pulsed charger..

If battery chargers were more reliable I may not have such an issue with it but I just see far to many failures and the resulting destroyed battery banks. With cold stored batteries I see leaving them plugged in and unattended akin to fogging your cars engine every time you shut it off. Not really necessary..

The other side is we have many unscrupulous manufacturers claiming "smart charging" selling pure unadulterated JUNK that is nothing of the "smart" sort...

This charger ruined a customers $1400.00 bank of NEW gel batteries charging them at over 16V on the GEL setting.... Smart? Hardly.??

Schumacher Ship n Shore Over Charging - YouTube



In a perfect world a proper float algorithm is fine but we just don't live in a perfect world. Battery chargers remain one of the most unreliable devices I see on boats. Please use them carefully...
__________________
______
-Maine Sail / CS-36T


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.




© Images In Posts Property of Compass Marine Inc.



Last edited by Maine Sail; 12-04-2011 at 11:09 AM.
Reply With Quote Quick reply to this message Share with Facebook
  #12  
Old 12-05-2011
Barquito's Avatar
Barquito
 
Join Date: Dec 2007
Location: Madison, WI
Posts: 2,070
Thanks: 0
Thanked 18 Times in 18 Posts
Rep Power: 8
Barquito is on a distinguished road
Thanks for the replies everyone.

Wow, the cold Wisconsin winter could actually save me some work? Cool. Next year, I will just make sure the batts are topped off, and leave them on the boat.

I have a pretty simple electrical system, with a house battery and a starter battery. Where would I look to see if there is a diode protecting back current?
Reply With Quote Quick reply to this message Share with Facebook
  #13  
Old 12-05-2011
Senior Member
 
Join Date: Aug 2006
Location: Arlington, VA
Posts: 1,812
Thanks: 0
Thanked 4 Times in 4 Posts
Rep Power: 10
btrayfors will become famous soon enough btrayfors will become famous soon enough
The above discussion worries me a bit. Not because some of the statements made are wrong, but because of the danger of their being misinterpreted.

I hope that no one takes away from this discussion the thought that it is always OK to charge your batteries before leaving them to themselves for the winter. While that might be a viable strategy in the cold frozen north, it is most definitely NOT a good idea for those habiting more temperate latitudes, i.e., those in which the temperatures during "winter" vary widely and/or stay relatively warm.

Keep in mind that all batteries have a self-discharge rate. Flooded batteries lose more each day/week/month from self-discharge than do, e.g., AGMs or gels, and this rate depends both on temperature and on age/condition of the battery.

If the ambient temp is very low, like near freezing, the self-discharge rate will be quite low. This is the condition which I believe MaineSail was referring to.

However, in areas like the Chesapeake daily temps during winter can vary widely....we even get some 70-degree days during December and January....and we can get some very cold (under zero degrees F) days and nights. If your boat is unheated the ambient temp will be affected by the outside temp and the amount of sunlight, as well as the degree of insulation.

What's the danger of leaving a battery less than fully charged? It can and will sulfate, and it will suffer from stratification (i.e., differing electrolyte concentration at various levels). These are the big killers of batteries which, unchecked, will result in loss of capacity and reduced overall life.

Remember, too, that even at a float voltage of 13.2-13.6, a flooded battery will sulfate and stratify somewhat. To avoid these conditions it is necessary to periodically increase the charge voltage to 14.4-14.8 or so.

If you're living in southern latitudes, say South Carolina to Florida or the Caribbean, don't even think about leaving your flooded batteries without at least some means to charge them periodically. In these climates, unattended flooded batteries can be killed by neglect in very short order.

Bill

Last edited by btrayfors; 12-05-2011 at 02:05 PM.
Reply With Quote Quick reply to this message Share with Facebook
  #14  
Old 12-23-2011
Senior Member
 
Join Date: Sep 2009
Location: Kingston Washington
Posts: 509
Thanks: 0
Thanked 2 Times in 2 Posts
Rep Power: 6
Waltthesalt is on a distinguished road
Look into an ACR relay. There's also the Duo-charge type regualtor units made for this. This cuts out the smaller battery when it's charged. Agree it's problematic to charge different types of batteries e.g. lead acid and gel.
__________________
Walt Elliott
Kingston WA
Puget Sound
Cal-29
Reply With Quote Quick reply to this message Share with Facebook
  #15  
Old 12-23-2011
mitiempo's Avatar
Senior Member
 
Join Date: Sep 2008
Location: Victoria B.C. Canada
Posts: 7,282
Thanks: 0
Thanked 79 Times in 70 Posts
Rep Power: 8
mitiempo will become famous soon enough mitiempo will become famous soon enough
Or an Echo Charge.
__________________
Brian
Living aboard in Victoria Harbour
Reply With Quote Quick reply to this message Share with Facebook
  #16  
Old 12-25-2011
Stu Jackson's Avatar
Senior Member
 
Join Date: Jul 2001
Posts: 810
Thanks: 0
Thanked 9 Times in 8 Posts
Rep Power: 14
Stu Jackson is on a distinguished road
Quote:
Originally Posted by LakeSuperiorGeezer View Post
I always float my lead acid batteries, whether deep cycle of starter batteries when there is infrequent use. Here is a web site that explains: How Does A Float Charger Work?
Drivel and quite unnecessary.

Charge the batteries up, disconnect them and store them in a cool place. Do what Maine Sail suggests.

Bill's right, too, but if the boat is in a "warmer" environment, most likely the folks are using the boat. Warmer weather = higher self discharge. Pretty easy to figure out: charge once a month, but don't leave 'em on float, because of what Bill said.

You could also thumb around the Ample Power Primer, download from the tech tab at Ample Power Company Home Page
__________________
Stu Jackson, C34, 1986, M25 engine, Rocna 10 (22#)

Last edited by Stu Jackson; 12-25-2011 at 01:49 PM.
Reply With Quote Quick reply to this message Share with Facebook
  #17  
Old 12-25-2011
Maine Sail's Avatar
Senior Member
 
Join Date: Jan 2003
Location: Maine Coast
Posts: 5,527
Thanks: 13
Thanked 146 Times in 112 Posts
Rep Power: 15
Maine Sail is just really nice Maine Sail is just really nice Maine Sail is just really nice Maine Sail is just really nice
Quote:
Originally Posted by Stu Jackson View Post
Drivel and quite unnecessary.

Charge the batteries up, disconnect them and store them in a cool place. Do what Maine Sail suggests.

You could also thumb around the Ample Power Primer, download from the tech tab at Ample Power Company Home Page
Unfortunately for those in hotter/warmer climates the use of a float charger can be necessary, but, I'd still prefer a timer connected to it so they would see absorption ever two or three weeks or so..

Unfortunately many "float currents" do not always prevent electrolyte stratification and with these chargers/maintainers, despite being "floated", the batteries. if wets, can still develop stratification. This is why in colder climates I much prefer to hit them a few times over the winter with a good absorption charge to get the electrolyte moving.

I have a customers battery on the bench right now, that I just finished equalizing, checking cell balance and charging to full. It is sitting at 13.5 volts and is seeing just 0.025A +/- to maintain the 13.5V. 0.025A does not and will not always prevent electrolyte stratification. A better quality marine charger will have a program that reverts back to absorption voltages every now and then to get the electrolyte moving.

I have a very nice charger, the boat is in our yard, and I still will not leave it on constantly. I them it yesterday for about 6 hours for the first time in about three to four weeks.

Some folks are comfortable with float chargers. I've seen too many failures, of all types of chargers, to trust them implicitly when I am not there.....
__________________
______
-Maine Sail / CS-36T


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.




© Images In Posts Property of Compass Marine Inc.


Reply With Quote Quick reply to this message Share with Facebook
  #18  
Old 12-25-2011
mitiempo's Avatar
Senior Member
 
Join Date: Sep 2008
Location: Victoria B.C. Canada
Posts: 7,282
Thanks: 0
Thanked 79 Times in 70 Posts
Rep Power: 8
mitiempo will become famous soon enough mitiempo will become famous soon enough
With some chargers like the Xantrex (not the best but the most prolific I think) you can switch from 3 stage to 2 stage charging. After a full charge is reached the charger sleeps until the voltage drops to 12.5 and it then comes on to fully charge before sleeping again. It refreshes the batteries each 21 days automatically in this mode. This is better for the batteries than a constant float and takes care of any self discharge issues.
__________________
Brian
Living aboard in Victoria Harbour
Reply With Quote Quick reply to this message Share with Facebook
Reply

Quick Reply
Message:
Options

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

Register Now

In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

 
Posting Rules
You may post new threads
You may post replies
You may post attachments
You may edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Batteries not charging Crunchtime Gear & Maintenance 5 09-06-2008 04:40 PM
Charging new batteries wchevron Gear & Maintenance 11 04-02-2008 03:00 PM
Charging batteries wchevron Gear & Maintenance 19 03-02-2008 11:21 AM
Charging 8d and 4d wet batteries Brezzin Gear & Maintenance 5 12-27-2006 02:22 PM
Charging Batteries Sue & Larry Gear and Maintenance Articles 0 09-25-2002 09:00 PM


All times are GMT -4. The time now is 12:20 PM.

Add to My Yahoo!         
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012

The SailNet.com store is owned and operated by a company independent of the SailNet.com forum. You are now leaving the SailNet forum. Click OK to continue or Cancel to return to the SailNet forum.