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Discussion Starter · #1 ·
My house batteries have lasted us pretty well as full time liveaboards spending a lot of time at anchor (all summer)
It is now time to change them and I am slightly confused.
We have 4 x 260 amp our batteries which are six volts.
We need more battery power if possible.
What is the best way to get as much power storage as possible?
would it be to go with 4x 6v batteries of 260amp hours or to get 4 x 12v batteries.
The batteries we have are normal wet cell batteries which seem to be the best value for money and as we have a very limited budget we will go the same way.
Are the better know batteries genuinely better than cheaper less well know brands.
Thank you for any advice.
 

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Physically 12 V or 6 V batteries will take nearly the same amount of volume for the same amount of energy. 12V batteries are two 6V batteries connected in the same box.
 

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Discussion Starter · #3 ·
Physically 12 V or 6 V batteries will take nearly the same amount of volume for the same amount of energy. 12V batteries are two 6V batteries connected in the same box.
Thanks Celenoglu.. there is not too much difference in the price between a 6v and a 12 v so it seems more sense to go for the 12v?
 

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There are tons of threads on this (these) exact topics on SailNet and other forums, so you might do some googling.

I think you will find that 6 volt batteries will give you more AH for your money, as well as being better suited for deep cycling service. As far as cost, consensus seems to be that warehouse batteries (Costco, Sam's Club) are just about as good as the name brands (like Trojan), but for substantially less cost.
 

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Two 6 volt batteries will give you considerable more amps (hp) than 2 12 volt batteries and you were mentioning that you wanted more power (like Tim, the tool man Taylor?), right? You may be able to find larger capacity 6v batteries with the same footprint, if you look around. If you went to 12 volt batteries, the connections would not be the same as the 2X6v. Caution.
 

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there is not too much difference in the price between a 6v and a 12 v so it seems more sense to go for the 12v?
On the contrary, there are HUGE differences between typical 12V "marine batteries" and 6V deep cycle batteries.

When buying batteries one must consider well beyond just Ah capacity. The most critical aspect to longevity will be the cycle life or how many cycles to 50% DOD you can pull off.

Most all 12V "deep cycle" marine batteries are imposters including top end brands like the Trojan 12V G-24, G-27 & G-31... They are not a true deep cycle battery and will yield far less cycles than a 6V GC2 battery.

Some brands will give more cycles than others in these group sizes but none compete directly with a GC2 in terms of cycle life..

You are not just buying Ah capacity you are buying cycle life. There are 12V golf cart batteries such as the Trojan T1275, and they do have the same cycle life as a 6V, but they are also taller, like the 6V, and a built to use the same plates as a GC2 battery. Group 24, 27 & 31 batteries simply do not have the plate thickness a GC2 battery does.....

For example in the Deka / Sea Volt / West Marine line you have starting, dual purpose and deep cycle G-24, 27 & 31 12V batteries which all share the same case.

However, they are only really deep cycle when compared to the starting or dual purpose batteries which share the identical case. They are not deep cycle when compared to the GC2 or other true deep cycle batteries..

Here's the data across the Deka / East Penn / West Marine line up:

Flooded Batteries - Group 24, 27, 31 & 6V GC2

12V Starting - Cycles to 50% = Not Rated
12V Dual Purpose - Cycles to 50% = 200
12V Deep Cycle - Cycles to 50% = 350
6V Golf Cart - Cycle to 50% = 700-1000


*Note: The above are LAB RATED cycles. Expect at least 50% less in the real world..


As you can see the 12V "deep cycle" battery is only a "deep cycle" when compared to the starting or dual purpose batteries it shares a case with. If you absolutely must buy a 12V Group 24, 27 or 31 buy the deep cycle version. In many cases this is all that will fit. It is easy to see that these are NOT deep cycle when compared to a real deep cycle battery.

The only ones that have lab rated cycles the same or close, to their own brands 6V batteries, are Lifeline and the US Battery DCXC 12V series (at least those are the claims). I know of no other brand that will rate their G-24, G-27 or G-31 at even half the cycles of their GC2 6V batteries. The Deka / East Penn / WM product is less than half and these are by far the most popular marine batteries out there....
 

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"What is the best way to get as much power storage as possible?"
I'm glad you asked that question.

The best way far and away the best way, is for you to give me all of your money, all the gold, all the cattle, all the women too, and I'll send you back some batteries. That's best for both of us.

Now, if you have any constraints, this is the time to say them. Any constraints on space, restricting battery size or height? Any requirements for, say, total capacity versus budget? And do intend to keep your outstanding, or obsolete, charging system? Or perhaps, switch to Lithium in order to get the most amps in the least space, while investing a lot more money in the batteries AND a new charging system and BMS to go with them?

Don't worry, we can discuss these things at length, while the women and gold and cattle are in transit. That's "best", really.
 

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Discussion Starter · #8 ·
"What is the best way to get as much power storage as possible?"
I'm glad you asked that question.

The best way far and away the best way, is for you to give me all of your money, all the gold, all the cattle, all the women too, and I'll send you back some batteries. That's best for both of us.

Now, if you have any constraints, this is the time to say them. Any constraints on space, restricting battery size or height? Any requirements for, say, total capacity versus budget? And do intend to keep your outstanding, or obsolete, charging system? Or perhaps, switch to Lithium in order to get the most amps in the least space, while investing a lot more money in the batteries AND a new charging system and BMS to go with them?

Don't worry, we can discuss these things at length, while the women and gold and cattle are in transit. That's "best", really.
Sounds a good deal, I have no gold, no cattle and a woman that castrates me on a monday and sows it back on on Sunday so she can do the same again. She does this as she knows I will do at least one thing wrong every minute (even when I sleep). She is on her way to you ... I presume my Lithium batteries are in transit.
 

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Agree with Mainesail totally.

If you have room use six 6 volt golf cart batteries to make a bank 1.5 times as large as before. If you have height you could go with 4 L-16 6 volt batteries - about 370 AH each for a total of 740 AH. They are built as well as smaller golf cart batteries but are a little longer and almost 18" high.

Trojan Battery Company
 

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Discussion Starter · #10 ·
Agree with Mainesail totally.

If you have room use six 6 volt golf cart batteries to make a bank 1.5 times as large as before. If you have height you could go with 4 L-16 6 volt batteries - about 370 AH each for a total of 740 AH. They are built as well as smaller golf cart batteries but are a little longer and almost 18" high.

Trojan Battery Company
Thank you to every one for their help and advice. Looking at the options and room available I think the best thing for me would be to go with the T105's 6v and increase the batteries from 4 to 6 to give me the extra power.
Again thank you for all your replies and advice.
 

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...I think the best thing for me would be to go with the T105's 6v and increase the batteries from 4 to 6 to give me the extra power.
Sounds like a good plan.

Look at Trojan's competition though like Deka/East Penn or US Battery. Comparable performance and lifespan at a better price.
 

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My current bank is 6 Deka 6v GC batteries, supposed to be equivalent to T 105s. I would have bought T105s had they been available. I think they use the same plate construction as the T 105s which is supposed to give longer life but lower CCA.

They are 4 years old now and still holding up well. Mostly they get pretty lightly cycled and get back up to 100% fairly often as I have 400 watts of tiltable solar.
 

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Discussion Starter · #13 ·
There in lies a dilema.
We need some more solar panels but what is the point when the batteries are not holding the charge too well. Our bank lasted 5-6 years which was pretty good really so I cannot complain.
 
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