Battery Selector: Run with ALL or 1 or 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
 Not a Member? 
  #1  
Old 08-30-2008
FishFinder's Avatar
Senior Member
 
Join Date: Feb 2008
Posts: 139
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 7
FishFinder is on a distinguished road
Battery Selector: Run with ALL or 1 or 2??

Well I just replaced my 28 year old alternator (on a 1980 Volvo MD7A) which has an internal regulator ... $360 bucks! All seems to be well, getting 14.4 volts at the battery when running at moderate RPMS. I want to be sure I don't fry this one.

I've never had a functioning alternator on a boat, and here is my setup: battery 1 is an engine starting battery, battery 2 is a higher-rated "house" battery. Both are 12v. My battery switch (also from 1980) is supposed to be a "make before break" type switch, but I have noticed sometimes when switching from bat 1 to 2 my electronics turn off. Hmm. And I have tested the alternator output, and only the battery selected by the battery switch receives a charge when the engine is running.

So my question is, how should I set the battery switch on my boat when starting and running the engine?? Should I trust my battery selector and switch between batteries while running? Would having it on "ALL" for starting/running be OK even if my 2 batteries are at different charge levels?

Thanks. My boat is a 1980 S2 9.2A.

Last edited by FishFinder; 08-30-2008 at 05:05 PM.
Reply With Quote Share with Facebook
  #2  
Old 08-30-2008
JimsCAL's Avatar
Senior Member
 
Join Date: May 2007
Location: Glen Cove, NY
Posts: 2,363
Thanks: 1
Thanked 31 Times in 30 Posts
Rep Power: 8
JimsCAL is on a distinguished road
With just a basic battery switch, you want BOTH on when running the engine to keep both batteries up. I would be concerned that the switch may have issues if the electronics shuts down when switching batteries (I assume you are not going through OFF but through BOTH. Until I had that issue resolved, I would start the engine on BOTH, leave it there until stopping the engine, then shift to the house battery. That should prevent frying the diodes in the alternator.
Reply With Quote Share with Facebook
  #3  
Old 08-30-2008
hellosailor's Avatar
Plausible Deniability
 
Join Date: Apr 2006
Posts: 10,418
Thanks: 1
Thanked 74 Times in 72 Posts
Rep Power: 10
hellosailor has a spectacular aura about hellosailor has a spectacular aura about
A 30-year old battery switch may not be making proper contact anymore, the contacts do wear and sometimes shift. I'd be tempted to replace it, or to install a battery combiner switch (West/Yadina or Hellroaring) which starts you on the starting battery, then combines both to charge/run once the alternator has come up to full voltage in a minute or two. When you shut the engine, it disconnects them again, so your starting battery is just isolated for starting use while you are on the house bank.
Reply With Quote Share with Facebook
  #4  
Old 08-30-2008
Senior Member
 
Join Date: May 2004
Location: Long Is.
Posts: 329
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 11
gc1111 is on a distinguished road
No matter what it says on the switch or how new it is, idle the engine before switching. It is rare to blow the diodes by switching at idle, even with an old fashioned switch. (Rare does not mean never though)
Reply With Quote Share with Facebook
  #5  
Old 08-30-2008
camaraderie's Avatar
moderate?
 
Join Date: May 2002
Location: East Coast
Posts: 13,878
Thanks: 0
Thanked 2 Times in 2 Posts
Rep Power: 15
camaraderie is a jewel in the rough camaraderie is a jewel in the rough camaraderie is a jewel in the rough
I ALWAYS use either battery one or two but not both when running the engine. Should you lose your belt or alternator output while motoring...you will drain the battery the switch is turned to...making it impossible to restart the engine after repairs. If you have the switch at both...you wil drain all. Ask me how I know!
My suggestion would be to charge your batteries at the dock and start and run on your house bank. Get an echo charger for your start battery but otherwise hold it in reserve for emergencies.
__________________
No longer posting. Reach me by PM!
Reply With Quote Share with Facebook
  #6  
Old 08-30-2008
Maine Sail's Avatar
Senior Member
 
Join Date: Jan 2003
Location: Maine Coast
Posts: 5,269
Thanks: 9
Thanked 112 Times in 82 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 gc1111 View Post
No matter what it says on the switch or how new it is, idle the engine before switching. It is rare to blow the diodes by switching at idle, even with an old fashioned switch. (Rare does not mean never though)
At idle, depending upon bank depletion, my alternar can put out well over 40 amps. Even a 3-5 amp output is enough to fry diodes! Idling the engine will do NOTHING to save your diodes from being fried if your bank was low when you started the engine.

I run a solar panel so my batts are always charged. My brother accidentally switched the battery switch off, before I shut down the motor, thinking he was helping and it fried the diodes even though the alt was only putting out about 3 amps at the time into a 99+% charged bank...


DO NOT use your "start" battery to start your engine use it as an "emergency" battery and you'll be fine if you add an ACR Automatic Charging Relay. Automatic charging relays only combine the banks when they sense voltages over about 13+ volts and they automatically disconnect at about the same..

In the last 15 years or so I have only once started my engine using my emergency bank and that was due to a stuck bilge float switch that killed my house bank..

Both my house and my start/emergency banks are deep cycle batts so that I'm combining batteries of like age type and size when charging. Contrary to popular belief you do not need a "start" type battery to start a sailboat aux engine..

If your batt switch is breaking before making buy a new one!!
__________________
______
-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; 08-30-2008 at 09:20 PM.
Reply With Quote Share with Facebook
  #7  
Old 08-31-2008
Senior Member
 
Join Date: May 2004
Location: Long Is.
Posts: 329
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 11
gc1111 is on a distinguished road
Quote:
Originally Posted by otaga05 View Post
I would suggest that you charge them separately, especially if they are different types of batteries as is often the case. Even if they are the same type, the two banks will often be in different charge states and require different voltage and current regulation for optimal charging. Eg, the house may be deeply discharged and require a different voltage than the starter which is close to float levels.
I disagree. What is optimal for each battery separately is not optimal for the system consisting of both. Think of them as a single bank consisting of paralleled batteries. The charging current will divide between them according to their needs.
Reply With Quote Share with Facebook
  #8  
Old 08-31-2008
Senior Member
 
Join Date: Aug 2006
Location: Arlington, VA
Posts: 1,807
Thanks: 0
Thanked 4 Times in 4 Posts
Rep Power: 9
btrayfors will become famous soon enough btrayfors will become famous soon enough
Otaga,

Good advice. Charge them separately or, better, use a Xantrex EchoCharge or a Balmar DuoCharge device (NOT a battery combiner or an isolator, etc.).

Sorry, halekai36, while I very much value your expertise and thoughts on many things, I have to disagree on your philosophy re: starting batteries.

The preferred setup is:

1. ONE large house bank, charged by every onboard device (battery charger, alternator, solar, wind, generator, etc.);

2. ONE starting battery, sized for your engine and NOT a deep-cycle battery; and

3. an EchoCharge or DuoCharge device, as per above.

This gives you a near bullet-proof, very efficient setup, and provides all the safety and redundancy you need.

Switches, fuses, breakers, etc. are a related but separate topic.

Bill
Reply With Quote Share with Facebook
  #9  
Old 08-31-2008
Senior Member
 
Join Date: May 2004
Location: Long Is.
Posts: 329
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 11
gc1111 is on a distinguished road
Another good design is to have an automotive alternator charging the starting battery and a separate, high output alternator with a 3-stage (or more) regulator/monitor system for the presumably much larger house bank.
Reply With Quote Share with Facebook
  #10  
Old 08-31-2008
Maine Sail's Avatar
Senior Member
 
Join Date: Jan 2003
Location: Maine Coast
Posts: 5,269
Thanks: 9
Thanked 112 Times in 82 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
Guys please read the OP. This guy just replaced his factory alt with another factory alternator (no smart regulation). He is most likely NOT going to spring for a $600.00-$1400.00 charging circuit upgrade based on his original post.

He can buy a cheap combiner and a new battery switch for less than $125.00 and be on his way and doing fine for short change. Dual alts or a Balmar configuration is certainly not in his cards having just spent $360.00 on a factory alt and being shocked about the cost of it.. I certainly don't get the feeling that he is a candidate for a gourmet charging circuit designed for long term cruising use..

"Well I just replaced my 28 year old alternator (on a 1980 Volvo MD7A) which has an internal regulator ... $360 bucks!"

ACR Charging Relay / Defender $79.99
__________________
______
-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; 08-31-2008 at 05:14 PM.
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
Installing a Automatic Battery Selector Switch artbyjody Gear & Maintenance 24 07-08-2008 07:07 PM
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
Boat Battery Power East Penn Manufr. Gear and Maintenance Articles 0 01-18-1999 07:00 PM


All times are GMT -4. The time now is 01:39 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.