Battery Sizing - am I crazy? - 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? 


Like Tree17Likes
Reply
 
LinkBack Thread Tools
  #1  
Old 11-18-2012
Member
 
Join Date: Aug 2006
Posts: 46
Thanks: 4
Thanked 0 Times in 0 Posts
Rep Power: 0
chartscharts is on a distinguished road
Battery Sizing - am I crazy?

All,

My CAL29 is in need of new batteries. The existing ones are shot and won't hold a charge. I wanted to solicit opinions about downsizing drastically.

My existing batteries are a bank of two of these: Trojan EV8D, 12Volt, 220AH@20hr, batteries. They are big and weigh a gazillion pounds a piece. More than I can easily remove myself, a big disadvantage.

My needs are modest. It primarily needs to start my Farymann A30, single cylinder, 10HP diesel. I have the usual running lights and house lights and VHF radio.

My sailing habits are almost exclusively day sailing. 2-3 times a year (on good years) I'll take it out for an overnight. I could use battery powered camping lanterns on those even, since it's not very often.

So I think I might be able to drastically downsize, allowing for easier and cheaper maintenance and replacement. Going to something like two of these:

EverStart Group Size 29DC Marine Battery: Automotive : Walmart.com

Am I crazy? What am I not thinking of?

-Charts
Reply With Quote Quick reply to this message Share with Facebook
  #2  
Old 11-18-2012
Senior Member
 
Join Date: Feb 2010
Location: Narragansett Bay
Posts: 9,459
Thanks: 10
Thanked 156 Times in 142 Posts
Rep Power: 6
Minnewaska will become famous soon enough Minnewaska will become famous soon enough
Re: Battery Sizing - am I crazy?

Those are big dogs at 155 lbs a piece. No shame in not wanting to haul those in and out.

If you can size a smaller battery at 2x your normal usage, then go for it. You could always replace the 8D with two smaller batts that are connected in parallel.
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Jeanneau 54DS

In the harsh marine environment, something is always in need of repair. Margaritas fix everything.
Reply With Quote Quick reply to this message Share with Facebook
  #3  
Old 11-18-2012
blt2ski's Avatar
Senior Member
 
Join Date: May 2005
Posts: 6,762
Thanks: 0
Thanked 25 Times in 24 Posts
Rep Power: 10
blt2ski will become famous soon enough
Re: Battery Sizing - am I crazy?

You need to do something like I have in my 30' boat. I have a typical size 24 starting battery for my 2 cy Yanmar, then a separate house battery that is a true deep cycle battery. They should not be run together for house lighting etc needs. You might find depending upon useage, a size 24, 27 or 31 12V lead DCycle batter will work for your needs. If you are going say a week at a time, then yes, keep the 2 8D's if that is what you have. Reality is, my setup will work for what you have. I did have a size 24 for the house, recently put in a 31 for a few more AHrs to work with.

Marty
__________________
She drives me boat,
I drives me dinghy!
Reply With Quote Quick reply to this message Share with Facebook
  #4  
Old 11-18-2012
asdf38's Avatar
Senior Member
 
Join Date: Jul 2010
Posts: 724
Thanks: 1
Thanked 8 Times in 8 Posts
Rep Power: 5
asdf38 is on a distinguished road
Re: Battery Sizing - am I crazy?

It's hard to argue with simplicity. It looks like you chose a deep cycle which in my opinion would be the best thing to do if you're going with one battery. Deep cycles still have plenty of cranking power and you're one cylinder isn't going to draw a ton.

However I don't know that particular battery and the usual battery purchasing cautions apply: if you want a deep cycle, make sure it's really a deep cycle. Deep cycles will always have the 20 hour Ah rate marked on them. That said I know plenty of people around here go with Wal-Mart. If you have a Sam's Club nearby also consider this:
http://www.sailnet.com/forums/electr...good-news.html

But also consider that you'll have no reserve bank should you leave a cabin light on and drain your one battery. Then you'll be stuck. One thing I considered with my 1 cylinder Yanmar was using a small $35 tractor battery as a reserve/start instead of a standard marine size one. You could consider that too if you wanted the usual reserve bank functionality but without much cost or weight.
http://www.samsclub.com/sams/duracel...tion=push#spec
jameswilson29 and Adele-H like this.
Reply With Quote Quick reply to this message Share with Facebook
  #5  
Old 11-18-2012
Senior Member
 
Join Date: Sep 2009
Location: Kingston Washington
Posts: 509
Thanks: 0
Thanked 2 Times in 2 Posts
Rep Power: 6
Waltthesalt is on a distinguished road
Re: Battery Sizing - am I crazy?

I agree with what's been said and your plan. If you're not going to do any rewiring then you want both the batteries to be the same type and age so that you charge them in parallel. It appears that someone wanted to have the battery bank be a larger capacity than needed for engine starting and light loading. The current, and more practical, thought to address this is to have a bigger deep cycle type battery for the hotel loads and a smaller starting battery that's spec'd to your engine requirements. with this type of arrangement however you'll need a different battery distribution panel which one battery is for the engine and the other for hotel loads, with a cross connect feature. You'll also need a charging circuit that uses a VSR relay or duo type charge that allows for the fact that the different batteries charge at differrent times and rates.
__________________
Walt Elliott
Kingston WA
Puget Sound
Cal-29
Reply With Quote Quick reply to this message Share with Facebook
  #6  
Old 11-19-2012
chucklesR's Avatar
Senior Member
 
Join Date: Sep 2007
Location: Pasadena Md - Magothy side
Posts: 5,979
Thanks: 10
Thanked 31 Times in 31 Posts
Rep Power: 10
chucklesR is a jewel in the rough chucklesR is a jewel in the rough chucklesR is a jewel in the rough
Re: Battery Sizing - am I crazy?

Somebody sold the previous owner a massive bank or batteries, or his usage was much different that yours.

Your plan is fine for your intended usage. Good luck getting the old ones out, use the boom as a lifting arm and wear something you don't like, or a plastic suit over it.
__________________
Lessons learned are opportunities earned.
Reply With Quote Quick reply to this message Share with Facebook
  #7  
Old 11-19-2012
Senior Member
 
Join Date: May 2007
Posts: 654
Thanks: 3
Thanked 4 Times in 4 Posts
Rep Power: 8
Siamese is on a distinguished road
Re: Battery Sizing - am I crazy?

I would not use the battery that you linked to at Walmart. Not sure if it's a true deep cycle, and I would DEFINITELY not buy a maintenance free battery for a boat.

Get a deep cycle 12v battery, that you can maintain. Without going into the mechanics of how they achieve "maintenance free" status, I will keep this brief and tell you it's not what you want.

I would typically suggest a bank of two 6v golf cart batteries and a 12v starting battery for emergencies, but for the needs you stated, a conventional lead acid deep cycle battery will serve you well. Keep some distilled water on board and top off the battery regularly.
Flybyknight likes this.
Reply With Quote Quick reply to this message Share with Facebook
  #8  
Old 11-19-2012
MedSailor's Avatar
Closet Powerboater
 
Join Date: Mar 2008
Location: Anacortes PNW
Posts: 2,954
Thanks: 162
Thanked 74 Times in 65 Posts
Rep Power: 7
MedSailor is on a distinguished road
Re: Battery Sizing - am I crazy?

Quote:
Originally Posted by chartscharts View Post

My sailing habits are almost exclusively day sailing. 2-3 times a year (on good years) I'll take it out for an overnight.
-Charts
Ummm.... I don't think you have too much battery capacity, I think you're just not sailing enough! Sail more and stay out longer and then you'll need the batteries!

Drastically downsizing your bank sounds like a very good idea. Just make sure to have 2 separate batteries: one starter style and one deep cycle. I think just about any size and brand would work from group 24 up based on your modest needs.

MedSailor
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


I have a sauna on my boat, therefore I win.
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote Quick reply to this message Share with Facebook
  #9  
Old 11-19-2012
hellosailor's Avatar
Senior Member
 
Join Date: Apr 2006
Posts: 10,873
Thanks: 2
Thanked 101 Times in 98 Posts
Rep Power: 10
hellosailor has a spectacular aura about hellosailor has a spectacular aura about
Re: Battery Sizing - am I crazy?

440AH of batteries for mostly daytripping?

You're not crazy. Get two 29D's, leave the battery switch on 'both' most of the time. When you drop the hook and there's a chance you might dawdle and run a battery down, then split the batteries, so you know you'll have one left for starting. No big deal and simplicity pretty much trumps all the theories and options.

In fact, for your use? One 29D or one 31 would probably suffice. Add a "battery brain" or other low-voltage cut-out on the positive post, and that will cut off all loads when you reach a low voltage, saving just enough battery so you can start the engine back up again. No master switch required, just reset it if you pull the battery down that low.
Reply With Quote Quick reply to this message Share with Facebook
  #10  
Old 11-19-2012
Barquito's Avatar
Barquito
 
Join Date: Dec 2007
Location: Madison, WI
Posts: 2,070
Thanks: 0
Thanked 18 Times in 18 Posts
Rep Power: 8
Barquito is on a distinguished road
Re: Battery Sizing - am I crazy?

I'm guessing you can exchange those huge batteries for a little cabbage($$).
__________________
Bristol 27
Cirque
Reply With Quote Quick reply to this message Share with Facebook
Reply

Quick Reply
Message:
Options

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

Register Now

In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




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
Battery Fuse Sizing - How, What...? Maine Sail Electrical Systems 28 09-21-2011 08:14 PM
Battery cable sizing micheck General Discussion (sailing related) 0 06-10-2011 05:50 PM
Battery Cable Sizing labatt Gear & Maintenance 11 02-20-2009 12:15 AM
Sizing battery cables scosch Gear & Maintenance 9 11-09-2007 02:35 AM
Sizing a Battery Charger for Windlass Battery btrayfors Gear & Maintenance 9 04-11-2007 01:43 AM


All times are GMT -4. The time now is 05:09 AM.

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.