Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 30-08-2012, 10:25   #1
Registered User

Join Date: Sep 2009
Posts: 331
12V bank + 24V bank?

At the moment 12V system in my boat. Have watermaker for 24V.

Am buying new batteries and solar panels at the moment and not sure if gonna run the watermaker thru at step up converter, or from a new small 24V bank.

Will also buy a new electric toilet and found one in stock for a good price (24V).

This is my options:
A) 525Ah batteries + 12-24V step up converter. All Solar panels to MPPT
pros: ONE big bank. Cons: a converter to fail


B) 420 Ah battery bank 12V, 105Ah 24V bank.Solar panels with a switch which bank to charge.
pros: no converter: cons: another battery bank

opinions?
__________________

__________________
andreas.mehlin is offline   Reply With Quote
Old 30-08-2012, 20:09   #2
Registered User

Join Date: May 2011
Posts: 132
Re: 12V bank + 24V bank?

You might consider converting the boat to 24 V, and running a 24 V to 12v converter. They are quite comen in the heavy equipment industry.
Or run two systems if you can mount a second alternator.
Or solit your 12 V system in to two banks and put a heavy duty double pole double throw switch between them set up to be series parallel. It sounds a little complicated but itís not too bad in reality. Though it is mostly done for heavy draw equipment such as bow thrusters and anchor winless. If you do this you might consider hooking your solar panels to the high side batteries. Just my two cents, Mike.
__________________

__________________
Florida Mike is offline   Reply With Quote
Old 30-08-2012, 20:18   #3
Registered User

Join Date: May 2011
Location: Toronto
Boat: Sandpiper 565
Posts: 2,943
Re: 12V bank + 24V bank?

How much current at 24v does the watermaker consume? Does it take both 12 and 24v in? Make and model, if we need to look it up? Ditto for the toilet.

My initial thought is that it doesn't make much sense to have a 24v boat system if only two devices require 24v.
__________________
Lake-Effect is offline   Reply With Quote
Old 30-08-2012, 21:01   #4
Moderator Emeritus
 
Pblais's Avatar

Join Date: Mar 2003
Location: Hayes, VA
Boat: Gozzard 36
Posts: 8,700
Images: 15
Send a message via Skype™ to Pblais
Re: 12V bank + 24V bank?

The main appeal for 24 volt systems is that on much larger boats the length of the runs requires some really thick wires. At some point the extra wire starts to cost more with 12 volt. It's mostly about the money. The design of the overall system is more important. I wouldn't just pick at small parts and details to make this decision. You always pay a penalty converting voltages so don't do it multiple times.
__________________
Paul Blais
s/v Bright Eyes Gozzard 36
37 15.7 N 76 28.9 W
Pblais is offline   Reply With Quote
Old 30-08-2012, 21:11   #5
Senior Cruiser
 
atoll's Avatar

Cruisers Forum Supporter

Join Date: Mar 2010
Location: gettin naughty on the beach in cornwall
Boat: 63 custom alloy sloop,macwester26,prout snowgoose 37 elite catamaran!
Posts: 9,312
Images: 75
Re: 12V bank + 24V bank?

Quote:
Originally Posted by Pblais View Post
The main appeal for 24 volt systems is that on much larger boats the length of the runs requires some really thick wires. At some point the extra wire starts to cost more with 12 volt. It's mostly about the money. The design of the overall system is more important. I wouldn't just pick at small parts and details to make this decision. You always pay a penalty converting voltages so don't do it multiple times.
+1
__________________
my catamaran building project updates http://www.cruisersforum.com/forums/...36#post2502136
atoll is online now   Reply With Quote
Old 30-08-2012, 23:35   #6
Moderator
 
Dockhead's Avatar

Cruisers Forum Supporter

Join Date: Mar 2009
Location: Cowes (Winter), Baltic (Summer) (the boat!); somewhere in the air (me!)
Boat: Cutter-Rigged Moody 54
Posts: 19,751
Re: 12V bank + 24V bank?

24 volts is better, but talking about converting your boat just to accommodate one 24v water maker is a major case of the tail wagging the dog. Sell it and buy a 12v one - simples.
__________________
Dockhead is offline   Reply With Quote
Old 31-08-2012, 10:28   #7
Marine Service Provider

Join Date: Dec 2003
Location: South Carolina
Boat: Philip Rhodes Custom
Posts: 395
Re: 12V bank + 24V bank?

Do some research. Starting current on a watermaker or toilet can be quite severe, (up to 10 times running current). You may have trouble finding a 12 to 24 volt DC-DC converter that can handle the load (that you can afford).
__________________

__________________
Andina Marie 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




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 06:21.


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.