Too many batteries?

[Badsanta]

If the GC, 31, 4D, 8D is just the outside case size how to you tell if it has thick or thin plates or deep cycle or not. How do you know. I hear alot of asumtions and generalities, is there anything on the label code that identifies the battery? Just asking.

[Lepke]

There are 2 8d batteries, 8dc and 8dd. 8dds have thicker plates for higher cycle rates.

I also removed my 8ds because of the trouble of getting them in and out. Now if one battery goes bad, I can change it myself.

With the change out for a large number of smaller batteries, I get competitive pricing.

[sparrowhawk1]

When I first moved aboard I made the mistake of overestimating what my solar panels would produce and got a large battery bank. What ended up happening is the batteries were never fully topped up. I now have 350 watts of solar, two small wind generators and a 425 amp hour battery bank. Which is a good balance for me. You can use only what you produce. The battery bank storage size should correlate to the extra amperage you produce. IMHO I think you'd be much better off putting your money into more solar panels and a smaller battery bank

[Ryan H]

Originally Posted by Badsanta

If the GC, 31, 4D, 8D is just the outside case size how to you tell if it has thick or thin plates or deep cycle or not. How do you know. I hear alot of asumtions and generalities, is there anything on the label code that identifies the battery? Just asking.

Typically, the easiest way you can tell is by the weight of the battery. One of Don Casey's books (cant remember if it's This Old Boat, or his Sailboat Maintenance series) has a break down of the expected weights of starting, deep cycle, and dual purpose six and twelve volt batteries. The numbers were just ball park figures, but useful when comparing batteries that claim to have the same capacity.

[a64pilot]

Originally Posted by belizesailor

Determined by who? Reference for that?

It's one of those trueisms I've heard forever, my best Marine reference would be Mainesail, I have yet to catch him being incorrect, but suspect the statement is meant to apply to the most commonly available, mainstream batteries.
For EVERY rule there are exceptions, I do not know, but assume you are correct with the Rolls batteries, they may be common where you are, but not where I am. Most people around here go down to Walmart and buy whatever they have that will fit.
As a General rule, especially if money is a concern, stay away from 12V batteries when using them as a house bank, if possible.
I haven't been able to find an amp hour cheaper than the GC-2's sold at Sam's Club here. Your location of course it may be different.


On edit, because I was really uncomfortable quoting Mainesail, even though I felt sure of what I had read, I went looking and found this http://www.pbase.com/mainecruising/deep_cycle_battery
In it he does state that two companies manufacture true deep cycle 8D's I believe and Rolls was one of those, but never having seen a Rolls battery, I probably just promply forgot that., sorry my mistake.

[a64pilot]

Originally Posted by Ryan H

Typically, the easiest way you can tell is by the weight of the battery.

This sounds nuts, but it's often very true, two batteries of the same case size will often have very different weights, the amount of lead being about the only thing that can make much difference, we can usually infer, more lead = better battery.
Lead is I think like $2 a lb now, so if you make a bazillion batteries and save say 2 lbs of lead out of each one, how much more money did you make?

[Mystic38]

Discussing batteries in isolation without considering both charging capacity and methods, plus daily consumption is simply not a fruitful discussion as the entire system needs to be considered as a balanced whole.

[belizesailor]

Originally Posted by a64pilot

It's one of those trueisms I've heard forever, my best Marine reference would be Mainesail, I have yet to catch him being incorrect, but suspect the statement is meant to apply to the most commonly available, mainstream batteries.
For EVERY rule there are exceptions, I do not know, but assume you are correct with the Rolls batteries, they may be common where you are, but not where I am. Most people around here go down to Walmart and buy whatever they have that will fit.
As a General rule, especially if money is a concern, stay away from 12V batteries when using them as a house bank, if possible.
I haven't been able to find an amp hour cheaper than the GC-2's sold at Sam's Club here. Your location of course it may be different.


On edit, because I was really uncomfortable quoting Mainesail, even though I felt sure of what I had read, I went looking and found this http://www.pbase.com/mainecruising/deep_cycle_battery
In it he does state that two companies manufacture true deep cycle 8D's I believe and Rolls was one of those, but never having seen a Rolls battery, I probably just promply forgot that., sorry my mistake.

Yes, if something gets repeated often enough, or posted on the Internet!, it tends to be accepted as true.

I think the same is true of the 12V trueism.

Thanks for the reference to MaineSail, I will read it. Certainly qualifies as an authoritative source.

Just for reference: My house bank is 2 x 8D, gels!, 12V...going on about a dozen years of service now and still viable (resting voltage is starting to decline though). Now that Ive read these trueisms, Im sure my battery bank will promptly fail !

[Maine Sail]

Originally Posted by belizesailor

Yes, if something gets repeated often enough, or posted on the Internet!, it tends to be accepted as true.

I think the same is true of the 12V trueism.

Thanks for the reference to MaineSail, I will read it. Certainly qualifies as an authoritative source.

Just for reference: My house bank is 2 x 8D, gels!, 12V...going on about a dozen years of service now and still viable (resting voltage is starting to decline though). Now that Ive read these trueisms, Im sure my battery bank will promptly fail !

8D GEL and 8D AGM are deep cycle, GEL more so than AGM. I currently have a GEL bank on a customer boat into its 16th year.

The only companies I know of are Rolls and Dyno Battery that make a true deep cycle flooded 4D or 8D battery. The rest of them are dual-purpose at best, and quite often grossly mislabeled starting-batteries. You will find many 4D & 8D flooded batteries that are starting or dual-purpose mislabeled as "deep cycle" this is false advertising but is done all day every day... Misleading? You betcha.....

The real question to ask when looking for a true deep cycle product is a very pointed one.

"Does your 4D or 8D flooded battery have the same lab rated cycle life as your golf cart deep cycle batteries do?"

If the answer is mumbling and stumbling you have your answer. Not one US maker of 4D or 8D flooded batteries, other than Dyno, and Rolls in Canada, has been able answer yes to that question when asked that way.

For example NAPA labels this Deka battery as a "premium deep cycle" battery

This is complete and utter rubbish because Deka / East Penn does not make a deep cycle version of their 4D & 8D batteries just a dual purpose & starting version. Still it does not stop sticker brands from lying to you...

Sadly the term "deep cycle" has been badly bastardized in the industry to include batteries as low as 250 cycles to as high as 1500+ cycles. The battery industry needs some serious self restraint in terms of marketing.......

[belizesailor]

Originally Posted by Maine Sail

...

Sadly the term "deep cycle" has been badly bastardized in the industry to include batteries as low as 250 cycles to as high as 1500+ cycles. The battery industry needs some serious self restraint in terms of marketing.......

Read your article referenced in a post above and my take away was that marketting is the core issue. There is nothing inherient in battery size or voltage which precludes it from being a true "deep cycle" (both are often mistated to be the case). The issue is that the marketeers can get away with labeling inferior batteries as "deep cycle".

Would you agree with that statement?





BTW: Thanks for all the good stuff you publish. :thumbup:

[Maine Sail]

Originally Posted by belizesailor

Read your article referenced in a post above and my take away was that marketting is the core issue. There is nothing inherient in battery size or voltage which precludes it from being a true "deep cycle" (both are often mistated to be the case). The issue is that the marketeers can get away with labeling inferior batteries as "deep cycle".

Would you agree with that statement?





BTW: Thanks for all the good stuff you publish. :thumbup:

Yes marketing is the key problem, and no, there apparently is an issue with certain case sizes in, flooded batteries, being true deep cycle...

I believe the industry needs to DEFINE what deep cycle is, and how many lab cycles to a specific BCI test this is. As of now the manufacturers are simply unwilling to do this and instead prefer to call a battery with 250 lab cycles deep cycle just as a battery that can do 1250 lab cycles is called deep cycle. Clearly both are not deep cycle batteries thus we are being LIED TO every day. Battery Council International (BCI) should be ashamed they allow this BS to continue.

In AGM and GEL formulations we do have true deep cycle batteries in Group 24, 27 & 31 case sizes as well as 4D & 8D but I have never seen a true deep cycle 24, 27 or 31 battery in flooded. Could it be made? I believe it could, but it has not, likely because while it would have good cycle life the Ah rating would drop. Sadly most boaters buy batteries by the Ah rating & the deep cycle sticker, not the cycle life rating.........

To me I define deep cycle as a minimum of being equal in lab cycle life to a GC2 or better. This is usually 700-1000 lab cycles. Most flooded 24, 27 & 31's max out at 250-600 lab cycles but to no "industry standard" so even those numbers are pretty unreliable and misleading.

I would also love to see the BCI encourage an industry standardized PSOC performance rating on any battery labeled as a deep cycle.

This of course will NEVER happen because the BCI is funded by the folks who love to lie and deceive the end user...

Rant off....

[a64pilot]

Originally Posted by belizesailor

Just for reference: My house bank is 2 x 8D, gels!, 12V...going on about a dozen years of service now and still viable (resting voltage is starting to decline though). Now that Ive read these trueisms, Im sure my battery bank will promptly fail !

I believe I did state that there were no 12V FLA batteries, obviously I was wrong, there are two, but that only applies to FLA batteries, I believe there may be several deep cycle 12V AGM's for example.
At least AGM's may be a rather expensive proposition as opposed to FLA's, unsure about Gels, but if you can get a dozen years out of them, then with a life cycle like that, the more expense up front may be worth it.
But I suspect many of us are making do with batteries that actually fit the definition of "dead" that is less than 80% of original capacity, myself I have the tendency to nurse one until it's well and truly dead before I buy new.

[motion30]

To avoid all the confusion and misleading labeling why not make it easy and just go with the 6 volt golf cart batteries. Those 8 D batteries are back breakers any hOw

[Cheechako]

Whatever batteries you use, you don't need more than enough for your daily needs with a bit of reserve. It sounds to me like you have way too much capacity, but as mentioned figure out what you need. Think of it this way: if you depleted them all, how would you ever recharge them back up?

[exMaggieDrum]

For the best price/performance for flooded wet cell golf cart deep cycle batteries you would be hard put to beat the Interstate batteries you can get at Costco. I put in lots of them when I was an apprentice electrician and many of my current sailing buddies use them. They can be abused and destroyed just like any batteries but they can also last a long time if maintain right. A step up would be the Trojans but dollar for dollar the Interstates would compare. Rolls and Surrettes are extremely pricey, and, as noted, not so easy to find. If the money matters I would go with the Interstates, maintain them, and replace them when they go bad. I would not put them in my boat going across the oceans but many have and done OK.