Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 12-01-2007, 07:07   #1
Registered User

Join Date: Aug 2006
Location: cairns australia
Boat: now floating easy37
Posts: 636
Images: 41
this may be dumb but...

what exactly stops you having your battery bank in series and in parrallel, i would love to run all my heavy draw items as 24v, now obviously people dont do this so why not?
__________________

__________________
northerncat is offline   Reply With Quote
Old 12-01-2007, 07:15   #2
Provocateur & Raconteur
 
knottybuoyz's Avatar

Cruisers Forum Supporter

Join Date: Nov 2005
Location: Iroquois, Ontario
Boat: Bateau.com TW31 Modified
Posts: 3,583
Images: 87
Heya NC

UP this way it's probably the scarcity 24V accessories, pumps, refers etc. At some point in the elec system you have to put in a dc/dc converter to power the 12V accessories, fans, radios, lights etc. If you figure in the cost to upgrade to 24V inverters, chargers, refers, larger cables etc. it gets expensive pretty quick. If you're building new and can locate the proper equip it probably is a good investement in going 24V for the energy efficiencies. I've decided to stick with what I know, 12V system for our next boat.

Starting from Scratch

Rick
__________________

__________________
Yours Aye! Rick
~^~^~^^~^~^~^~^~^~^~^~~^~^~~^~^~^^~~^~^
"It's not the boat "you built" until you've sworn at it, bled on it, sweated over it, cried beside it and then threatened to haul the POS outside and burn it!"
knottybuoyz is offline   Reply With Quote
Old 12-01-2007, 09:06   #3
Registered User
 
Doghouse's Avatar

Join Date: May 2006
Location: Hampton Roads, va
Boat: Catalina 387 - Magical Dreamer
Posts: 176
Images: 1
1. there is no way to break the bridges so you would basicly have a 24V short accross the 2 series jumbers you have shown there. Result would be a big POP!

2 with a number of larger relays and a couple of switches you could build a system that could do that properly, but in the likely event of a relay failure (stuck relay) again you would open yourself up to a big pop!
__________________
Doghouse is offline   Reply With Quote
Old 12-01-2007, 13:36   #4
Senior Cruiser
 
Alan Wheeler's Avatar

Cruisers Forum Supporter

Join Date: Dec 2003
Location: Marlborough Sounds. New Zealand
Boat: Hartley Tahitian 45ft. Leisure Lady
Posts: 8,038
Images: 102
There is a way of doing it by getting in between individual Cells. This was an easy thing to do when the older style banks with the lead straps going from cell to cell were used. Not common to see anymore. But the issue is that the cell in the middel somewhere goes flat and effectively open circuits the rest of the bank. It won't charge equally anymore and you effectively wreck the bank.
Going to a true 24V system has great advantages. Mainly in that you get better current through cables to high load devices. The disadvantages are as Knottybouyz has stated. 24V stuff is expensive and then you have to regulate for 12V equipment not available in 24V. I do think 24V and 48V systems are far supperior to 12V, so you just have to weigh up the cost for you. Certainly large vessels would greatly benifit from higher voltage systems because of cable run issues. Smaller vessels may not benifit at all.
__________________
Wheels

For God so loved the world..........He didn't send a committee.
Alan Wheeler is offline   Reply With Quote
Old 12-01-2007, 16:37   #5
Senior Cruiser
 
44'cruisingcat's Avatar

Cruisers Forum Supporter

Join Date: Sep 2006
Posts: 7,454
Images: 69
Sean, if you have a look at your circuit diagram you will see that you have the +ve of the top battery connected to the -ve of the second one, but you also have the -ve of the top battery connected to the -ve of the second one - so you have +ve connected to -ve on the top battery - a direct short. (repeated with all the others)
__________________
44'cruisingcat is offline   Reply With Quote
Old 12-01-2007, 20:09   #6
Registered User

Join Date: Aug 2006
Location: cairns australia
Boat: now floating easy37
Posts: 636
Images: 41
but isnt connecting batteries in series any way a dead short?
__________________
northerncat is offline   Reply With Quote
Old 12-01-2007, 20:57   #7
Senior Cruiser
 
44'cruisingcat's Avatar

Cruisers Forum Supporter

Join Date: Sep 2006
Posts: 7,454
Images: 69
No, unless you make a complete circuit. That is, you connect the positive of a cell or battery to it's own negative. What we call a "battery" is made up of (usually 6 in a 12 volt battery) cells connected pos-neg-pos-neg (in series)but the first pos and the last neg are not connected to each other. If you do that you get sparks. In your diagram there, the top battery has it's pos connected directly to it's own neg.
(in fact so does the second one)
__________________
44'cruisingcat is offline   Reply With Quote
Old 13-01-2007, 03:25   #8
Moderator Emeritus
 
GordMay's Avatar

Join Date: Mar 2003
Location: Thunder Bay, Ontario - 48-29N x 89-20W
Boat: (Cruiser Living On Dirt)
Posts: 31,579
Images: 240
These Battery Connection Diagrams show how 2, 6, and 12 volt batteries are connected for 12, 24, and 48 volt operation:
Goto: Battery Wiring Diagrams
advancedenergysolution.com/Resources/diagrams.htm

and


These connection diagrams illustrate how to get increased current (more power) by using parallel wiring and how to increase voltage levels by using series wiring. You can do both using series and parallel wiring in combinations:
Goto: Advanced Tutorials: Battery Wiring Diagrams for Solar Energy Systems
freesunpower.com/battery_diagrams.php
__________________
Gord May
"If you didn't have the time or money to do it right in the first place, when will you get the time/$ to fix it?"



GordMay is offline   Reply With Quote
Old 14-01-2007, 08:20   #9
Registered User

Join Date: Apr 2006
Boat: MacGregor 26M Lynx
Posts: 352
The savings with 24v vers 12v is not that big of a deal and may even cost you more money, unless you are going to need a high amp windless. You will save money on wire. You can have both, now we are getting complex and into bigger boat stuff.
__________________
Lynx is offline   Reply With Quote
Old 14-01-2007, 11:39   #10
Senior Cruiser
 
Alan Wheeler's Avatar

Cruisers Forum Supporter

Join Date: Dec 2003
Location: Marlborough Sounds. New Zealand
Boat: Hartley Tahitian 45ft. Leisure Lady
Posts: 8,038
Images: 102
24V is most definatly a lot more expensive in every way. The problem 24V mainly tries to solve is cable length issues. A 50ft boat is IMO about the point of crossover between going 24V or remaining with 12V. 60ft is definatly getting into the 24V range and above that is most certainly. Otherwise cable size for the run distances becomes extreme.
__________________
Wheels

For God so loved the world..........He didn't send a committee.
Alan Wheeler is offline   Reply With Quote
Old 14-01-2007, 12:48   #11
Senior Cruiser
 
delmarrey's Avatar

Cruisers Forum Supporter

Join Date: Mar 2003
Location: Now in Blaine, WA
Boat: Modified Choate 40
Posts: 10,702
Images: 122
cable length

That's one of the reasons I put a battery up forward for the winch. It was much EZ'r and at the same cost to run a 2 X #10 wire w/ a combiner then 2 X 30' of 00 cable. Plus, I have and extra battery now, just in case.............................._/)
__________________
delmarrey is offline   Reply With Quote
Old 14-01-2007, 15:37   #12
Registered User

Join Date: Aug 2006
Location: cairns australia
Boat: now floating easy37
Posts: 636
Images: 41
my anchor winch is rated at 80 amps wouldnt this this be a bit of a massive draw for one battery ??
sean
__________________
northerncat is offline   Reply With Quote
Old 14-01-2007, 16:48   #13
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
Quote:
my anchor winch is rated at 80 amps wouldn't this this be a bit of a massive draw for one battery ??
Yes it would but for how long? If it took a half hour to raise the anchor it might matter more than if it were just 10 minutes. Recharging the battery gets to be the issue depending on how you set up the charger. You can't be sending a huge number of amps up front to charge the battery. Probably start a nice sized fire in seconds. That means you need a way to limit the amps going forward to recharge the anchor battery.
__________________
Paul Blais
s/v Bright Eyes Gozzard 36
37 15.7 N 76 28.9 W
Pblais is offline   Reply With Quote
Old 14-01-2007, 18:36   #14
Registered User

Join Date: Sep 2006
Location: Keswick, ON Canada
Boat: Islander 36
Posts: 81
I hope I can provide a few thoughts for Sean. You have to size your battery according to the expected load and time. The best "rule of thumb" is to multiply number of amps by the time of usage. Add 30% to the result and pick a battery that has AmperHours size next above your score. Assume that you need 80A to be used for 15 min (0.25 hr).
80 x 0.25 x 1.3 = 26 AH. - so, if you find 30AH deep cycle battery it would probably suffice for one/two uses and it has to be recharged. However, if you would like to raise your anchor more than twice on one charge than the battery has to be much bigger. Such battery would last for several years if not discharged below 80% of its rated capacity.
The other question is the size of the wires. Delmarrey indicated 2/0 on the size of his boat. If you use such size wires and length you are facing ~0.5V drop in your voltage at the windlass (~5% of battery nominal voltage). This is a little more complicated as also inrush current should be taken into account. In any case, his decision to move battery close to the winch was very practical.
I suggest that you should find an electrical engineer in your marina who would advise you on the size of battery and wires to feed your winch.
Have fun....
__________________
Rodz is offline   Reply With Quote
Old 14-01-2007, 21:00   #15
Registered User

Join Date: Nov 2006
Location: Third Coast, TEXAS
Boat: Gulfstar 36 Motorsailer & Albin 25 Trawler
Posts: 168
I dont know about others, but I have my engine running when I pull anchor because if you pull anchor and then the engine doesnt start you can be in a world of trouble. Even if I have wind and will be pulling the sails up after pulling the anchor, I still want the engine running as a back up if something goes wrong like a slide jambing on the main. And I dont see pulling the sails up BEFORE pulling the anchor as a wise departure either. After all if you are hauling the anchor, you are probably close to shore and s**t does happen....#8-)

With the engine running and a proper sized alternator, there probably would not be much discharge of the battery anyway. A boat of any size at all should have a 100 amp alternator, so the alternator would be able to supply all 80 amps if need be. I have a small 50hp diesel and the alternator is 100 amps.
__________________

__________________
jimisbell 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
Seeking a tutorial for a Garmin 76CSx Galaxy Marine Electronics 13 13-09-2006 08:23
Software upgrades, new features and more... Andy R Forum News & Announcements 98 29-06-2006 01:35



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 16:13.


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.