Both Batteries Drain Even When Only Bank Is Selected - 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 > General Interest Forums > Gear & Maintenance > Electrical Systems
 Not a Member? 
  #1  
Old 09-29-2009
Junior Member
 
Join Date: May 2009
Posts: 10
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
pkilty is on a distinguished road
Both Batteries Drain Even When Only Bank Is Selected

Hi All,

I have recently purchased a 1982 Pearson 37. I have spent the last month discovering the things that let's just say the previous owner failed to mention and the surveyor failed to find. It's a great boat, but in need of some love, cash and a lot of elbow grease. I have three batteries that I know are not properly wired. One deep cycle type 24 paralleled with a wet 4d for my #1 and a single type 24 deep cycle for my # 2. I think they are all of different ages and plan on scrapping them before next season. I have a "new" 85a alternator with internal regulator.

My problem is that with the selector switch off all three batteries will hold a
decent charge for several weeks. With only #1 or #2 battery on overnight with just a very small hotel load, both #1 and #2 are dead by morning.

I have checked draw on the main distribution panel and after thinking I had an aha moment found the vhf wired to the hot bus.This accounted for the draw when the panel was 1st energized.

The only thing common besides the switch is the alternator.

Any thoughts?

Thanks,

pkilty
Reply With Quote Share with Facebook
  #2  
Old 09-30-2009
mitiempo's Avatar
Senior Member
 
Join Date: Sep 2008
Location: Victoria B.C. Canada
Posts: 6,775
Thanks: 0
Thanked 51 Times in 42 Posts
Rep Power: 6
mitiempo will become famous soon enough
Hi
Something is definitely wired wrong. Trace the wiring from batteries to main switch - I assume it's 1-2-both-off type. Find out if any wires go anywhere besides the switch and where they go. Make sure the main switch is wired properly. The hot from bank 1 should go to #1 position, hot from bank 2 should go to #2 position and common (output) should go to your distribution panel and the engine starter. Somehow I think your battery banks are common to each other regardless of the switch position and there is a draw on them with the switch on #1 or #2. I guess you should get in there with a multimeter and with the switch on 1 or 2 see which items are getting voltage. That's my best guess right now. Good luck and let us know what happens.
Brian
Reply With Quote Share with Facebook
  #3  
Old 09-30-2009
Senior Member
 
Join Date: Oct 2006
Location: Virginia
Posts: 722
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 8
badsanta is on a distinguished road
Write it down and make a map. If you cant actually see and feel the wire the whole long way it is no guarantee it goes where you think. Label the wires as you figure out what goes to what. You also may have a bad battery that drains the system. I would take them all out to a battery store and have them charger and tested. Also batteries should be the same type and size and age as different types (gel and wet) charge at different rates.
__________________
That derelict boat was another dream for somebody else, don't let it be your nightmare and a waste of your life.
Reply With Quote Share with Facebook
  #4  
Old 09-30-2009
Zanshin's Avatar
Senior Member
 
Join Date: Aug 2006
Location: Germany
Posts: 2,065
Thanks: 0
Thanked 11 Times in 11 Posts
Rep Power: 8
Zanshin is on a distinguished road
Do you have a multimeter? If so, perhaps your alternator is either wired incorrectly or broken. Can you disconnect the cables from the alternator and measure resistance (simple "infinite" or "full'" continuity is enough)?
__________________

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

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote Share with Facebook
  #5  
Old 09-30-2009
Senior Member
 
Join Date: Aug 2006
Location: Arlington, VA
Posts: 1,796
Thanks: 0
Thanked 4 Times in 4 Posts
Rep Power: 9
btrayfors will become famous soon enough btrayfors will become famous soon enough
Quote:
Originally Posted by pkilty View Post
Hi All,

....

The only thing common besides the switch is the alternator.

Any thoughts?

Thanks,

pkilty
There you have it! If the alternator is indeed "common" to both banks, then they are effectively paralleled, unless there is a battery isolator installed.

Bill
Reply With Quote Share with Facebook
  #6  
Old 09-30-2009
mitiempo's Avatar
Senior Member
 
Join Date: Sep 2008
Location: Victoria B.C. Canada
Posts: 6,775
Thanks: 0
Thanked 51 Times in 42 Posts
Rep Power: 6
mitiempo will become famous soon enough
btrayfors
yes, but that doesn't explain the dead batteries with only a small load overnight. There has to be another issue.
Brian
Reply With Quote Share with Facebook
  #7  
Old 09-30-2009
Zanshin's Avatar
Senior Member
 
Join Date: Aug 2006
Location: Germany
Posts: 2,065
Thanks: 0
Thanked 11 Times in 11 Posts
Rep Power: 8
Zanshin is on a distinguished road
Here I assumed that your alternator had 2 outputs and that an internal diode might have been broken. With a multimeter, measure the voltage across the + and - poles of one battery after the switch has been set to "off" for a while. With all devices switched off and breakers off, switch "on" and see if the voltage changes - even a small short dip will tell you that you've got a consumer switched on or have a current drain in your power lines. Short of an ammeter you'll have to start disconnecting devices one by one to find your problem source.
__________________

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

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote Share with Facebook
  #8  
Old 09-30-2009
Senior Member
 
Join Date: May 2007
Posts: 526
Thanks: 1
Thanked 1 Time in 1 Post
Rep Power: 7
SteveInMD is on a distinguished road
I think you need to use a load test device on the batteries to see if they are actually good or not. If not, trouble shooting is going to be difficult.
Reply With Quote Share with Facebook
  #9  
Old 09-30-2009
davidpm's Avatar
Senior Member
 
Join Date: Oct 2007
Location: Madison
Posts: 3,488
Thanks: 131
Thanked 33 Times in 26 Posts
Rep Power: 7
davidpm is on a distinguished road
Quote:
Originally Posted by SteveInMD View Post
I think you need to use a load test device on the batteries to see if they are actually good or not. If not, trouble shooting is going to be difficult.

I second this option. First thing to find out is the condition of the batteries.

Some bad cells can cause all kinds of odd behavior. They seem to hold a charge unders some conditions then loose the charge way too fast.

First rule of troubleshooting. Don't go first to the exotic problems, rule out the mundane first.

I have taken my batteries to the nearest NAPPA store and let them charge and load test them.
They can tell you their exact condition.

Last edited by davidpm; 09-30-2009 at 03:29 PM.
Reply With Quote Share with Facebook
  #10  
Old 09-30-2009
timebandit's Avatar
Senior Member
 
Join Date: Sep 2002
Posts: 928
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 12
timebandit is on a distinguished road
I thinking the batteries also.

It seems like with three batteries you should be able to pull 10 amps all night and not kill the batteries and it should be easy to find a load that big.
__________________
Rick
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Mac 25
Copernicus
Southern California
I am not a prejudice racist sexist bigot. I just hate stupid people.
Reply With Quote Share with Facebook
Reply


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
Paralleling Batteries dave.verry Gear & Maintenance 79 11-27-2006 11:19 AM
Battery Bank Design Kevin Jeffrey Gear and Maintenance Articles 0 05-12-2003 08:00 PM
Battery Bank Design Kevin Jeffrey Cruising Articles 0 05-12-2003 08:00 PM
Installing a New Battery Bank Sue & Larry Gear and Maintenance Articles 0 09-26-2002 08:00 PM


All times are GMT -4. The time now is 12:39 AM.

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