Sam's Club Batteries 6V Golf Cart and Group 31 Deep Cycle?

[Jeff Barnes]

I have used 4 6-volt AGMs in my CD36. They are Lifeline batteries and provide 400 Ah of capacity which I have found adequate (but could always use more). I have electric fridge, windlass, and lots of electronics (inlcuding radar,weather fax and SSB) and charge the bank with a Balmar 75A alternator, Heart Interface external charger and a Link 10 monitor. All four batteries fit in the "L" section of the port settee.

The AGMs have performed flawlessly for 6 years, even after abusing them once by drawaing them down over 360Ah. They are maintenance free, clean, and stay in the boat all winter without charging here in NE. Correct charging voltage for the acceptance and float stages however is critical.

<img width=" 600" src="http://i285.photobucket.com/albums/ll49 ... G_0200.jpg">

[mattlydon]

2 weeks of Fridge seems magical - everything I've read says battery-driven refrigeration can't work. What refrigeration system are you using?

Matt

[TheSandPebbles]

What's the benefit of using 2 6V batteries over one good quality 12V battery? It seems to me like it would save space just to use the 12V battery. And thanks for the previous answers.

[Oswego John]

Here's a real non technical reason that is so easy to shoot holes in, but what the hay, here goes nothing.

One big battery has more cubic area than one small battery.

Two battery cases contain more cubic area than one battery case.

A larger total cubic area allows more room for more cell plates than a smaller cubic area.

More total cell plate surface area makes for greater ampere/hour capacity.

Now if only Larry De Mers, the battery guru would chime in......

O J
Hey,I told you it would be non technical.

[Maine Sail]

The benefits of 6V batteries over a single 12v battery is longevity & price. 6V batts have thicker and taller plates, they can cycle deeper and withstand more cycles than a comparable, in amp hours, 12V battery. They are also less $$$ than a comparable 12v battery and can yield more ah's in the taller sizes than 12v batteries do for the same footprint.

A single group 29/31 wet cell usually has about a 105-110 ah rating though some companies claim 120, which IMHO is usually just a tweak in the rating method more than the battery actually putting out 120 ah.

Two six volt batteries of the standard GC2 size will usually yield between 220 & 225 ah's when wired in series for 12v.

Basic wiring:

Series doubles voltage - Two 6v batts in series is 12v but the ah's remain at 225 ah.

Parallel doubles amp hour rating - Two 12 volt batts in parallel double the ah's but the voltage remains at 12v.


Four golf cart batteries wired in series/parallel will yield a 12v bank of roughly 450 ah's but take up a similar footprint as 4 group 24 12V batteries which would yield only about 320 amp hours.



Think about it this way in terms of plate thickness. A single GC2 6v battery is about the size of one group 24 12v battery only slightly taller.

The 12v battery has six 2 volt cells inside the case where the 6v battery has only three 2 volt cells. Because of this the 6v batteries are true deep cycle with significantly thicker plates. There is a reason nearly every golf cart that runs on batteries uses 6v batteries..

If you only have room for three house batteries then a bank of 12 volt batteries would have to suffice as you need matched pairs of 6v batteries to create 12 volts. If you have room for two or four house batteries 6v's are less expensive and will take more abuse.[/img]

[Jeff Barnes]

Matt,

Thefridge is a Adler-Barbour cold machine. Maintains temp between 39 and 47 degrees depending onoutside temperature. Added insulation to the rather inadequate original ice box. It can run for 4 days with my batteriry system before they need recharging. Not sure why you thought 2 weeks! The fridge system uses about 55Ah per day.

Jeff

[John Danicic]

To add what Maine Sail says.

The six volt batteries are also easier to move around then a similar amp hour 12 battery. Although they weigh 62 lbs a piece, a single 440 amp hr, 12 volt battery would weigh in at 128 lbs.

Which would you rather lift up and move around?

Sail on

John Danicic
CD36 - Mariah - #124
Lake Superior - The Apostle Islands
CDSOA # 655

[David VanDenburgh]

Ariel has two six-volt Trojan T-105 golf cart batteries wired in series for her house bank, and a single 12-volt marine battery for her starting battery.

[TheSandPebbles]

After reading this and other threads on batteries, it sounds like the best thing for me to do is replace my 3 12V batteries with 2 6V golf cart batteries and one marine 12V battery.
I'm planning to put ALEXANDRA in the water for the first time (for me) on the 28th. greatly anticipating my first sail on her...
-Perry