6 Volt, reserve vs weight - SailNet Community
 
LinkBack Thread Tools
post #1 of 6 Old 05-06-2003 Thread Starter
Senior Member
 
Join Date: Jan 2003
Posts: 339
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 13
 
6 Volt, reserve vs weight

Am I fooling myself here? Would I be better off with a 4 battery bank than running two 6 volts battieries? My boat is set up for live aboard and I would LOVE to be able to run the refrigerator even when I am away from shore power. It is my only major draw but there is anyways the other small items like running lights, radio, and maybe a reading light. help which way should I go????
jbanta is offline  
Quote Quick Reply Share with Facebook
Sponsored Links
Advertisement
 
post #2 of 6 Old 05-06-2003
Senior Member
 
Join Date: Jul 2000
Posts: 172
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 16
 
6 Volt, reserve vs weight

The answer lies in how much room do you have for batteries and what type? i.e. group 27/group24 or golf cart batteries?

Two 6v golf cart batteries will typically have more reserve power i.e. amp hours of current than two of the other types.
Figure out how many batteries of each type you could install, then add up the amp hour rating of that battery combo.

Batteries in parallel combine the total amphour rating of all the batteries. i.e. two 12 volt batteries rated at 90 amp hours each will give you 12 v and 180 amphours.

Batteries in series combine the total voltage of the batteries. i.e. two 6v batteries in series give 12v and the amp hour rating of one battery.

fairwinds,
Jim
joub is offline  
Quote Quick Reply Share with Facebook
post #3 of 6 Old 05-06-2003 Thread Starter
Senior Member
 
Join Date: Jan 2003
Posts: 339
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 13
 
6 Volt, reserve vs weight

I have space to go either way. I am still concerned about the weight. The golf cart battiers are HEAVY and some day I am going to put a new saildrive where I just ripped out the OMC. Damn those batteries are huge. Some 20" tall. The engine compartment is the only space I have that can handle anything that big. I need to find a 12 Volt with the same kinda reserve as a 6 Volt.
jbanta is offline  
Quote Quick Reply Share with Facebook
post #4 of 6 Old 05-07-2003
Senior Member
 
Join Date: Jul 2000
Posts: 172
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 16
 
6 Volt, reserve vs weight

Don''t know what type of golf cart batteries you have seen, but the ones in my boat are not much heavier than the group 27 batteries (12v) that I replaced, yet they have about a 45 amp hour greater capacity.

Looking at the West Marine catalog, I see GC2 batteries (i.e. golf cart) are rated at 215ah (mine are 225ah) and are 10.25 x 7.125 x 10.8" and weigh 63.5 lbs. The group 27 batteries (12v) are rated at 90 ah and are 12.5 x 6.75 x 9.4" and weigh 53 lbs.

So a pair of the 6v batteries weigh 20 lbs more and give you 35 ah more capacity than a pair of the 12 volters.

Is that what you had in mind?

Jim

joub is offline  
Quote Quick Reply Share with Facebook
post #5 of 6 Old 05-07-2003 Thread Starter
Senior Member
 
Join Date: Jan 2003
Posts: 339
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 13
 
6 Volt, reserve vs weight

I was looking at West Marine too but I was looking at the 8L16 @113 lbs 370 ah
jbanta is offline  
Quote Quick Reply Share with Facebook
post #6 of 6 Old 05-07-2003
Senior Member
 
Join Date: Jul 2000
Posts: 172
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 16
 
6 Volt, reserve vs weight

Four GC2''s would give you 430Ah at 252 lbs which should be enough capacity and not too heavy.

I''ve heard the figure of 100 Ah per day as a rough rule of thumb for a boat with refrigeration. Of course there are many variables, but that is probably a good estimate.

Don''t know how closely you watch your nickles, but I bought by golf cart batteries at Sam''s club for around $45 each. Some told me they were cheap and wouldn''t last but got 4 1/2 years service out of a pair. Of course they were floating on the charger most of the time and not used a lot in a full cruising enviornment which might make a difference.

430Ah would give you the capacity to keep in that 50 to 80% charge range that seems to be the optimum level for battery life and shorter charge time.
joub is offline  
Quote Quick Reply 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:
OR

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
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Forum Replies Last Post
What can you tell from the numbers? brazilnut Boat Review and Purchase Forum 10 07-01-2009 04:09 PM
J-40 for Long Distance Cruising ? ddimaui Boat Review and Purchase Forum 66 12-30-2008 06:54 PM
Displacement vs Length TADIAS General Discussion (sailing related) 5 12-16-2003 06:54 AM
Displaced weight vs Dry Weight mikehoyt Gear & Maintenance 7 10-23-2002 05:01 AM
6 Volt Batteries vs 12 Volt ABullard Gear & Maintenance 10 09-06-2001 05:41 PM

Posting Rules  
You may post new threads
You may 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 On
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome