Return to the home page...

Go Back   Moyer Marine Atomic 4 Community - Home of the Afourians > Discussion Topics > Electrical

Reply
 
Thread Tools Display Modes
  #1   IP: 71.183.116.60
Old 04-20-2012, 06:59 PM
Loki9's Avatar
Loki9 Loki9 is offline
 
Join Date: Jul 2011
Location: Long Island, NY
Posts: 382
Thanks: 0
Thanked 3 Times in 3 Posts
Battery Switch Question

My P30 has two 12V batteries and the usual off->1->all->2 big red battery switch. Printed right on the switch it says "do not change when engine is running". Why is that, what's the harm? It seems to be the make-before-break type of switch, so that if I have the cabin lights on and slowly move the switch from 1 to "all" to 2 the lights never flicker.

Is it safe to switch when the engine is idling and the alternator is not working?

I'd like to use one battery for starting the engine only and the other battery for everything else. However, can I start the A4 using "1" and then switch to "2" to charge the other battery only? I assume this will charge the battery that needs it faster than using the "all" position.
__________________
Jeff Taylor
Baltic 38DP
Reply With Quote
  #2   IP: 184.0.176.66
Old 04-20-2012, 11:16 PM
hanleyclifford hanleyclifford is offline
 
Join Date: Mar 2010
Posts: 6,803
Thanks: 121
Thanked 152 Times in 128 Posts
Talking

Although many switches will be said to be "make before break" I have never really trusted that claim. If you like to move battery switches with engine running it is best to use switches with field disconnect circuits. If an alternator is allowed to run even for a few seconds with no battery connected it is possible to fry the alternator.
Reply With Quote
  #3   IP: 76.118.149.176
Old 04-21-2012, 06:25 AM
smosher smosher is offline
Afourian MVP
 
Join Date: Jun 2006
Posts: 489
Thanks: 0
Thanked 3 Times in 3 Posts
Some Alternators are more forgiving than others and the Motorola is not forgiving at all.

I have a P30 and I believe it came with break before make as the PO
had the diodes replaced regularly, I have all of his repair data. When I
was redoing the wiring I noticed that there's a cutout for the batt switch
and it was replaced. I have checked it and it is a make before break. I think he
thought either the switch or bad or a break before make. When I had the motorola alt I switched while the engine was running, didn't have any issues.

I have now replaced the alt with the 55A and I have also switched while running with no issues.

I don't switch them often, I keep it on one battery and use the other as a emergency in case the one drains down. I did have to switch it last year
when the new walmart battery died at the end of season
Reply With Quote
  #4   IP: 71.206.74.65
Old 04-21-2012, 05:55 PM
KeysCatalina's Avatar
KeysCatalina KeysCatalina is offline
Senior Member
 
Join Date: Jun 2011
Location: Key West
Posts: 28
Thanks: 0
Thanked 0 Times in 0 Posts
perko makes a off-1-all-2 switch with a alternator field disconnect its about $6 more than the same switch without it. There are 2 extra poles on the back of the switch to connect directly to the alternator or diobe (regulator/rectifier). I believe certain alternators are more susceptible to being damaged if you turn the switch "OFF" while engine is running because you are taking the load off the alternator/regulator/rectifier/diodes... and that dc current has no where to go when the battery is disconnected from the circuit on the fly.

seems like the above posters have some good info i can contribute the attached diagram i got from perko as well.
Attached Images
 
__________________
1978 Catalina Yachts C27
1993 Bayliner Classic 2250
1986 South Seas 16 - sold
2012 Suzuki GSXR 1000 - The Commuter
2007 Suzuki GSXR 750 - 31k miles, sold
2006 Suzuki GSXR 600 - 9k miles, sold
"Therefore I say unto you, what things soever ye desire, when ye pray, believe that ye receive, and ye shall have.
And when ye stand praying, forgive, if ye have ought against any: That your Father also which is in heaven may forgive you your trespasses." Mark 11:24

Last edited by KeysCatalina; 04-21-2012 at 05:58 PM.
Reply With Quote
Reply

Thread Tools
Display Modes

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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Battery Charger Question Jimmy Electrical 10 02-01-2012 12:24 AM
Wiring spaghetti ndutton Electrical 35 09-07-2011 07:18 AM
Alternator Issues Capt Don Q Electrical 9 12-04-2009 02:55 AM
Battery Switch: Field Disconnect Protection SEMIJim Electrical 12 04-30-2009 02:55 PM
Battery Replacement question: what if, what not, and how JasperWindvane Electrical 4 12-24-2006 11:35 AM


All times are GMT -4. The time now is 11:38 AM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2018, vBulletin Solutions, Inc.


Universal® is a registered trademark of Westerbeke Corporation

Copyright © 2004-2018 Moyer Marine Inc.

All Rights Reserved