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Old 18-05-2007, 11:15   #16
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I believe AGM are just a vastly improved type of gel cel. Instead of just having gelled electrolyte around the plates, there are woven fiberglass mats that is saturated with electrolytic gel. Much more efficient, prevents a whole host of issues. Drying, shifting....

What gets me is that the AGM batteries currently have manufacturers warrenties of about 3 years. I compare this to a Rolls individual wet cell battery that comes with a 10 year warrenty. Trojans are 5 years, I think. If I were going around the world, I'd definately go with the Rolls. Nothing like having to replace the batteries in some place like Sri Lanka. If I were just going to go cruising for 3 month hops and was going to regularly return to the states, I might elect an AGM solution.

But, this is given that my bank is going to be VERY inconvient to replace. Two of the batteries are readily accessible and can be tackled out. One I am going to have to cut open the battery box to remove, the other, I wish I knew how they got in there! I think removing the engine would be easier. I can't imagine replacing them without damaging something else.

Dollar per unit of usage, I think the Wet Celled batteris are far more economical than the AGM. That is if you excluded the value of your time that you'd spend maintaining the wet celled batteries, vs. the no maintenance AGMs.

Heck, hopefully, they will fix the battery issues and come up with some additional solutions here in the near future. Ah, the optimist in me.
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Old 18-05-2007, 11:52   #17
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Ah, future is here: Last 6 times longer than AGMs (2000 cycles with 80 percent discharge vs 300 for AGMs), weighs about 1/2 of the Lead/AGM/Gel batteries, and are maintenence free (Woohoo!!!!) And cost 5 times as much (awwwwwww). Per charge, they may be almost cost effective. Almost.... Then you look at getting 800 cycles from a golf cart batteries which cost half of the AGMs and it starts making even less sense....

http://www.valence.com/pdffiles/U-Charge_XP_DS.pdf

So, golf cart batteries it will be for me.
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Old 18-05-2007, 12:45   #18
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Quote:
What gets me is that the AGM batteries currently have manufacturers warrenties of about 3 years.
Actually Lifelines are 5 years.

I agree with you that Rolls are top notch... but I will never again own another wet. Between the maintenance, having to haul around that water, having to be flat, the recharge time, the venting... etc, I think they are a dinosaur and most (Rolls and some others excluded) are junk. Exception are the weekend warriors where that investment is a waste of money.

I tell people that are gearing up: Batteries are critical pieces, buy good ones. Go AGM. If you do not want to pony up what is about $100-150 more for Lifelines, get Dekas.

Just my opinion... I respect your posts!!!! No offense!!! (SMILE!) I just dissagree.

Take care.

- CD
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Old 18-05-2007, 14:53   #19
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Don't get me wrong! I love AGM. I have them for my starter batteries and that's the only thing I'll use in my shore vehicles. They take charges faster and more efficiently, they can be tipped, no worries about venting hydrogen etc... Like I said my only issue is cost per usable life amp and not having to go through the process of replacing them. If they had a 7 year AGM, even if it were more expensive than the Rolls solution, I'd probably pick that. But, the folks I have spoken to have not been impressed with the overall longevity of their deep cycle AGMs.
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Old 18-05-2007, 16:06   #20
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battery question

Ativa, I cruised 3 years and 22,000 miles (Seattle to Cyprus via Pacific and Indian Oceans) with 4 Interstate golf carts as my main bank, and they were in great shape at the end. My only charging was a balmar alternator and a four winds 2 generator. We were seldom near shore power. IMHO wet batteries will work fine for extended cruising by the non-wealthy. The interstate batteries were not junk. If occasionally topping off wet batteries is too much work, then so are oil changes and bottom paint. Good luck with your batteries and sailing!
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Old 18-05-2007, 17:57   #21
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Might as well close this thread. He just posted another thread saying he had already installed his new batteries.
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Old 18-05-2007, 19:20   #22
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"I believe AGM are just a vastly improved type of gel cel."
Not at all. AGM and Gel are both "sealed valve regulated" batteries. But in order to "control" the liquid electrolyte, a thickening agent is added to make gel. That agent also effectively adds "useless filler" to the electrolyte.
In AGM, there is no useless filler. There is instead a thin glass scrim (glass mat) between the plates, which acts as a separator and allows evenly and tightly controlled plate spacing. Then, a conventional electrolyte is added--but added very sparingly, so these are also called "Starved electrolyte" batteries.
You could call each one a "kind" of wet call, but aside from both AGM and Gel being able to use sealed batteries--they have nothing much in common. Since they use different charging voltages and regimens, confusing them can be deadly to them.

The work of topping off wet cells can also be cut by using recombinant battery caps, couple of bucks more per cell.

Rolls and Surette will be the first to tell you, they don't make "consumer" batteries, they make "industrial" batteries, at way higher cost, and the different construction is what allows the longer warranty and service claims--and that higher cost. Which is pretty much wasted, unless the buyer knows charging systems and takes proper care of their batteries!
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Old 18-05-2007, 19:24   #23
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Yah...probably should end things but I did want to add something about warranties from the perspective of one who was directly involved in setting warranties on automotive batteries at one point in my life.
WARRANTIES ARE A MARKETING TOOL AND HAVE NO RELATION TO THE ACTUAL PERFORMANCE OF THE PRODUCT. As long as we knew the average life of a particular battery in use (by the ORIGINAL purchaser) and our actual cost to produce a new one (different than retail!!!) we could put virtually any warranty we wanted on a product simply by building in the cost of servicing that warranty into the products initial price.
Don't rely on warranties to judge the quality of a product!
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Old 19-05-2007, 07:03   #24
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I agree to some degree with a warrenty assesment. It is often times a marketing tool. But isn't a probability analysis performed to determine cost of a warrenty program vs. improvement in sales and revenue? Would a company warrenty their product to such an extent that they were having to honor the warrenty constantly, at great expense? I guess my thinking is that if there should be some correlation between the expected service life of a product and a companies willingness to stand behind their product.

A much better assement should be the number of discharge cycles each battery is rated for. That's what truly sent me to the other side. I compared AGM's to Rolls Wet cell. I was REALLY surprised by what I read.

Thanks for the clarification Gel cell vs AGM. I don't know how that got stuck in my mind??? I may have to do all that reading over again, it has been too long since I did the analysis.

Cheers, and fair winds.
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Old 19-05-2007, 20:21   #25
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Well, an MBA friend of mine happened to head up the warranty analysis unit of a major corporation some years ago. His job--his full time job, with staff--was to find out the failure percentage expected of every product in the line, every unit, every month, until they all went belly-up, or a long long time had passed.

In most major corporations there is a similar unit. They know exactly how many pieces will fail, and when they will fail, and a determination is made to set aside money for warranty repairs/replacements. They HAVE TO do that to meet conventional accounting standards, forecasting reserves against actual income from sales.

Someone makes a decision about how long the warranty will be, and what will be the most profitable (a complex term<G>) warranty terms and length to offer. Marketing will be involved in that, sure. But to say that warranty is JUST a marketing decision? Uh-uh. Marketing, controlled by corporate policy which includes questions of reputation and long-term customers and repeat business, versus the immediate profit.

When the job is done properly (the failure forecast) a company can make good profits. If they botch it...Can you say "Ooopsie" ? <G>

I also knew a sailor who was head of a manufacturing company, which quietly polled some of us product users about a new product they were going to introduce at 1/5th of the competition's lowest priced ($100,000+US) product. The competition (all of it, including themselves) bundled a 1-year service contract into other products, which ran about 2% of the purchase cost. This would mean a 10% difference in the offering price for the new blockbuster product, so they asked how we'd feel about a 90-day service plan, with the usual option to renew it annually after that.

Apparently eeryone else said about the same thing I said, which was that I don't buy a $20 TOASTER with a warranty that short. I know the warranty service costs money, I really don't are about that since I'm going to buy the service contract anyway. I just want to see the first year bundled in, whatever the price is, as their assurance that the product works.

Funny thing...the product shipped, at a price 10% higher than they originally planned, with the full year's service contract included. And sold like hotcakes.

Good marketing.<G>

But if you know the product is reliable--you know the extra cost of the warranty is minimal, and you CAN offer the customer that reassurance without jacking up the price. Given two toasters, one with a 90-day warranty and one with a 5-year warranty, at the same price or a buck higher, which one would you choose?<G>
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Old 20-05-2007, 06:48   #26
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Right... I didn't mean to imply that warranty decisions are made in a vaccuum.
For many products...the warranty is not used as a marketing tool or seen to have much advantage and it is simply used to AVOID costs and spell out the LIMITED responsibilities of a mfr. in order to avoid any implied warranty.
When it comes to batteries (and new cars for example) though...the warranty is cleary used to provide a competitive advantage in MANY cases. It helps to sell the product or justify a higher price if the battery is a 5 year battery instead of a 3 year battery. Marketing departments are heavily involved in this decision and as HS points out...they have all the data they need to market they product at the right price and warranty terms.

There is a certain muffler co. which has long advertised free mufflers as long as you own your car even though they know the muffler will likely come back at them. Why? Because they know the true net cost of the muffler and they know the additional replacement part/service income each return for a free muffler generates. Most people probably think their muffler is the greatest due to the marketing and it is simply not so.
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Old 20-05-2007, 07:09   #27
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Thanks for all the advice.. I went with the Interstate 8D deep cycle.
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Old 20-05-2007, 09:37   #28
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I've been working in the boat biz for thirty-plus years. Here is what I have gleaned: There is no value greater, in terms of amp hours per pound carried aboard, than conventional wet-cell batteries, of whatever size configuration. All the other wet-cell varieties (AGM, etc.) offer ONLY the advantage of storage and maintenance options. Second, I only have had Rolls or Surrette batteries aboard my own boat, which will celebrate its thirtieth anniversary next March. That means three changes of batteries. There is a reason for people spending lots of money for those batteries. Mine also have the fancy platinum caps that limit water replenishment to a couple ounces every six months. I figure they have been worth the investment. Third, and equally significant, I have used PulseTech battery conditioners for the last eighteen years. These are devices used by the military on their combat armored equipment, fire and police departments, long-range truckers, taxis and ambulances, as well as mere mortals. They remove sulfation from battery cells, period. If you use a battery hydrometer to examine the specific gravity of the electrolyte, you see ONLY the highest reading of green. That's because the sulfates are all in solution, providing the highest voltage, capacity and life expectancy.

Until we see some exotic batteries reach the market, we're stuck with heavy variants on lead-acid. Why not come to terms with your batteries, treat them with care, and size them to your needs? It beats having to wrestle them out of your boat every couple years, spend too much money over your lifetime, and still worry if there will be enough juice to crank the engine or send off a rescue message.
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Old 20-05-2007, 11:46   #29
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"There is a certain muffler co. " Yes, I know them.<G> Met them in college days and didn't use them then or since. The hardware they install is cheap junk, the labor that you MUST pay for in order to get the warranty service, more than pays for the next round of junk. Like the companies that say "free refills for life, (Shhhh! Just pay this outrageous shipping and handling fee each time!)"

Roy, AFAIK no one has actually proven "pulse" charging systems work any better than conventional "smart" chargers. Even PulseTech's own web pages cleverly omit the actual paper that was "accepted" by the SAE [translation: They submitted a paper, purpose and content unknown and cleverly not published by the authors on their own web site].

And their claim for the military use--except, they don't say what products, and whether the military actually buys and uses their *products* or just their training and conventional chargers or solar trickle chargers.

And their claim for "university studies" plural, when the only reference is a terribly vague one that can be read as "Some nursing school in Minnesota tested batteries using our solar trickle chargers versus no charging at all, and found out the trickle chargers work better than nothing."

Yeah, I know, it could just be they hired a really really poor writer. But I read their site the same way I read my first Blimpie's Hero Sandwich: "Where's the Meat??!" It just isn't there. And if they had good facts--they'd have to be fools not to share them. A great new charging idea, from fools? Dunno, but it won't sell me. Might be as good as anything else, but I don't see any reason to think it is better. I've been hearing claims of miracle de-sulphaters longer than I've been driving. Never seen one, just keep hearing the claims.<G>
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Old 20-05-2007, 11:58   #30
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Gosh, I guess the hundred or so customers that I've installed them for must be wondering why they haven't had to replace batteries. You know, I know it's hard to accept new technologies, but after seeing the electrolyte at such high specific gravity, after years of service, a reasonable person could draw a conclusion that the sulfates are being drawn off the plates. Can you provide an alternate source for a high specific gravity of the electrolyte? Is it your practice to demean what you have no experience in? Even Scripps Institute of Oceanography (my next door neighbor) is using these units. Perhaps it's mass delusion.
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