Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 23-10-2014, 03:43   #16
Registered User
 
cajucito's Avatar

Join Date: Oct 2012
Location: Tipperary & Dublin Ireland
Boat: Beneteau 44cc
Posts: 83
Re: Can I still get 12V from two 12V batteries in series

A dedicated extra 12v Battery very close to the windlass is the best solution charged from the 24v system using a regulator. No long 12v Heavy cables. Tapping 12v off the 24v system is a definate no no as the windlass is a high power item especially under load when breaking out. I had probs with my bow thruster for a long time , when I fitted an extra battery right next to the thruster it solved every problem I ever had. Having a dedicated battery on heavy load devices such as windlass electric winches or thrusters is a great idea as it isolates the rest of the system from low voltage dropouts when the 'big current' device comes under heavy loads. Thrusters can draw several hundred amps.
__________________

__________________
cajucito is offline   Reply With Quote
Old 25-10-2014, 08:58   #17
Zil
Registered User

Join Date: Mar 2013
Location: South Jersey
Posts: 239
Re: Can I still get 12V from two 12V batteries in series

In my good old days, we converted hot rods from 6v to 12 volts. Changed the generator, the bulbs, but run the 6 volt starter on 12 volts. Some early Ford V8s were set up with a solinoid on a 12v battery to just power the 6 volt starter. Would spin faster, but did not have other problems.
__________________

__________________
Zil is offline   Reply With Quote
Old 25-10-2014, 09:15   #18
cruiser

Join Date: Feb 2008
Location: North Charleston, SC
Boat: Camano Troll
Posts: 4,669
Re: Can I still get 12V from two 12V batteries in series

Quote:
Originally Posted by Zil View Post
In my good old days, we converted hot rods from 6v to 12 volts. Changed the generator, the bulbs, but run the 6 volt starter on 12 volts. Some early Ford V8s were set up with a solinoid on a 12v battery to just power the 6 volt starter. Would spin faster, but did not have other problems.
The heater blew good too!
__________________
rwidman is offline   Reply With Quote
Old 25-10-2014, 09:27   #19
Registered User
 
Cadence's Avatar

Join Date: Dec 2008
Location: SC
Boat: None,build the one shown of glass, had many from 6' to 48'.
Posts: 6,063
Re: Can I still get 12V from two 12V batteries in series

Quote:
Originally Posted by Zil View Post
In my good old days, we converted hot rods from 6v to 12 volts. Changed the generator, the bulbs, but run the 6 volt starter on 12 volts. Some early Ford V8s were set up with a solinoid on a 12v battery to just power the 6 volt starter. Would spin faster, but did not have other problems.
You forgot the coil.
__________________
Cadence is online now   Reply With Quote
Old 25-10-2014, 11:14   #20
֍֎֍֎֍֎֍֎֍֎

Cruisers Forum Supporter

Join Date: Apr 2006
Posts: 13,053
Re: Can I still get 12V from two 12V batteries in series

Except, starter motors are high impulse motors. And high impulse motors are very very different from electronic instruments or much of anything else. You can overvolt many motors with no damage, if the power is applied briefly enough. But sooner or later, the excess voltage also overheats them and burns them out. The same way that the normal voltage will burn them out, if it is applied for just a little too long.

It's like giving dog chow to a goldfish. Probably would work for a while. Just isn't the best way to raise prize goldfish.
__________________
hellosailor is offline   Reply With Quote
Old 25-10-2014, 12:13   #21
Registered User

Join Date: Mar 2013
Location: Marina del Rey, CA
Boat: '46 Creekmore
Posts: 25
Re: Can I still get 12V from two 12V batteries in series




Make sure the 24v charger is not charging those batts when you are powering your 12v windless off them, or you will fry it.
__________________
jordiebsocal is offline   Reply With Quote
Old 28-10-2014, 22:24   #22
Registered User

Join Date: Apr 2013
Location: Brisbane, Australia
Boat: Cavalier 37
Posts: 3
Images: 1
Re: Can I still get 12V from two 12V batteries in series

I have the reverse problem. I want to install a 24V thruster on a boat that has a 12V system. I am thinking of installing a second 12V battery in series with the start battery as shown is this wiring diagram.



My questions.
  1. Has anyone done something similar to this and did it work?
  2. If so, what did you use for the diode to prevent a short circuit on the charging circuit? I think a 50 A bridge rectifier may work, using the DC output terminals as the diode.
  3. What sort of reverse current was there through the diode and did that cause any flattening of battery issues?

An obvious solution is to install two extra batteries and a 12-24v charging system. I'd like to avoid that if possible.
__________________
Kipper1258 is offline   Reply With Quote
Old 29-10-2014, 14:25   #23
Marine Service Provider

Join Date: Oct 2011
Posts: 1,205
Re: Can I still get 12V from two 12V batteries in series

A better solution.

Quote:
Originally Posted by FlyingCloud1937 View Post
Going to require some additional HD wire pulls, but a solution is at hand without moving the bats.
Lloyd

texasindustrialelectric.com

Quote:
Originally Posted by Kipper1258 View Post
I have the reverse problem. I want to install a 24V thruster on a boat that has a 12V system. I am thinking of installing a second 12V battery in series with the start battery as shown is this wiring diagram.



My questions.
  1. Has anyone done something similar to this and did it work?
  2. If so, what did you use for the diode to prevent a short circuit on the charging circuit? I think a 50 A bridge rectifier may work, using the DC output terminals as the diode.
  3. What sort of reverse current was there through the diode and did that cause any flattening of battery issues?

An obvious solution is to install two extra batteries and a 12-24v charging system. I'd like to avoid that if possible.
__________________
FlyingCloud1937 is offline   Reply With Quote
Old 29-10-2014, 14:35   #24
Registered User
 
Cadence's Avatar

Join Date: Dec 2008
Location: SC
Boat: None,build the one shown of glass, had many from 6' to 48'.
Posts: 6,063
Re: Can I still get 12V from two 12V batteries in series

Quote:
Originally Posted by Kipper1258 View Post
I have the reverse problem. I want to install a 24V thruster on a boat that has a 12V system. I am thinking of installing a second 12V battery in series with the start battery as shown is this wiring diagram.



My questions.
  1. Has anyone done something similar to this and did it work?
  2. If so, what did you use for the diode to prevent a short circuit on the charging circuit? I think a 50 A bridge rectifier may work, using the DC output terminals as the diode.
  3. What sort of reverse current was there through the diode and did that cause any flattening of battery issues?

An obvious solution is to install two extra batteries and a 12-24v charging system. I'd like to avoid that if possible.
You would be shorting across your gen. output.
__________________
Cadence is online now   Reply With Quote
Old 29-10-2014, 16:07   #25
Registered User

Join Date: Apr 2013
Location: Brisbane, Australia
Boat: Cavalier 37
Posts: 3
Images: 1
Re: Can I still get 12V from two 12V batteries in series

Quote:
Originally Posted by Cadence View Post
You would be shorting across your gen. output.
Yep. Suppose that's why I'm not an electrical engineer. Thanks.
__________________
Kipper1258 is offline   Reply With Quote
Old 29-10-2014, 16:24   #26
Registered User

Join Date: Apr 2013
Location: Brisbane, Australia
Boat: Cavalier 37
Posts: 3
Images: 1
Re: Can I still get 12V from two 12V batteries in series

Quote:
Originally Posted by FlyingCloud1937 View Post
A better solution.
Thanks. What I am looking for. One more question, any issues with this type of parallel switch for driving a thruster. Looks like it also looks after the charging side of the second battery.

__________________
Kipper1258 is offline   Reply With Quote
Old 29-10-2014, 19:48   #27
Marine Service Provider

Join Date: Oct 2011
Posts: 1,205
Re: Can I still get 12V from two 12V batteries in series

No problem, as long as your charge back amps don't exceed 45amps. The relay/combiner is rated at 1500 amps intermittent. I doubt your thruster would exceed 150 amps.

Lloyd

Quote:
Originally Posted by Kipper1258 View Post
Thanks. What I am looking for. One more question, any issues with this type of parallel switch for driving a thruster. Looks like it also looks after the charging side of the second battery.

__________________

__________________
FlyingCloud1937 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
I Only Have Two Batteries - Which Batteries Should I Use? LifesAnAdventure Electrical: Batteries, Generators & Solar 11 04-06-2014 19:29
Two Engines, Two Alternators, Two Banks scurvy dog Electrical: Batteries, Generators & Solar 2 16-02-2014 06:48
Two solo cruisers , Two boats OR Two Captains One Boat colo.sail General Sailing Forum 8 17-12-2011 17:36
Amp Hours on Joining Two 6v Batteries to Make 12v . . . Ocean Roads Electrical: Batteries, Generators & Solar 7 04-05-2011 22:19
Can I separate two pairs of batteries? Stevebellevue Electrical: Batteries, Generators & Solar 4 03-04-2011 08:24



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 15:25.


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.