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Old 01-29-2012, 06:57 AM   #15
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I have AGM's in nearly everthing I own. Pricier, but less maintence than flooded and will take 100% charge as opposed to flooded at only 80%. Also not adversely affected by continious deep discharge cycle.
When replacing batteries in a battery bank, do them all at the same time. One old or weak battery can cause overcharging of good batteries in the bank.

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Old 01-29-2012, 07:08 AM   #16
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I am confused. My lead acid batteries take 100% charge and stable out at 12.6 volts. I do Equalize them once every six months.

Mike Canter
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Old 01-29-2012, 03:03 PM   #17
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more info.

sorry about the lack of info. these are wet cell 12 volt house batteries. approximately 2 years in service. the boss and me self were discussing it last eve. seems we have had weird things happening since they were married to the coach. minor but noticeable. no
Sams club here. would have to drive to Vegas, hmmm, thanks again.c wood
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Old 01-29-2012, 05:11 PM   #18
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After 9 years I replaced my Interstate U-2200's, they were still working but it's coming up on the camping season and I didn't want them going out where it would be hard to find them.
I considered the Costco's (no Sam's clubs here) but couldn't find enough info on the them so I got Interstate's again. New designation but spec's show they're pretty much the same ones.

AGM's are still lead acid batteries, their only advantages are lower/no maintenance and no fumes. At about twice the price I really couldn't justify a reason for unsing them.
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Old 01-30-2012, 12:04 PM   #19
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Like Mr D, I find it hard to justify the expense of AGM batteries. Over the years I've tried Costco deep cycle as well as Interstate. I currently have Trojan GC batteries and don't think I will ever use anything else. I've had them for almost 5 years and they still perform extremely well. They cost more than Interstate and club store batteries, but are still much less than AGM's. I keep them flooded with a Pro-Fill system, so maintenance is a breeze.

Just my two cents...

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Old 01-30-2012, 03:41 PM   #20
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AGM, or Absorbed Glass Mat Batteries

A newer type of sealed battery uses "Absorbed Glass Mats", or AGM between the plates. This is a very fine fiber Boron-Silicate glass mat. These type of batteries have all the advantages of gelled, but can take much more abuse. We sell the Concorde (and Lifeline, made by Concorde) AGM batteries. These are also called "starved electrolyte", as the mat is about 95% saturated rather than fully soaked. That also means that they will not leak acid even if broken.
AGM batteries have several advantages over both gelled and flooded, at about the same cost as gelled:

Since all the electrolyte (acid) is contained in the glass mats, they cannot spill, even if broken. This also means that since they are non-hazardous, the shipping costs are lower. In addition, since there is no liquid to freeze and expand, they are practically immune from freezing damage.
Nearly all AGM batteries are "recombinant" - what that means is that the Oxygen and Hydrogen recombine INSIDE the battery. These use gas phase transfer of oxygen to the negative plates to recombine them back into water while charging and prevent the loss of water through electrolysis. The recombining is typically 99+% efficient, so almost no water is lost.
The charging voltages are the same as for any standard battery - no need for any special adjustments or problems with incompatible chargers or charge controls. And, since the internal resistance is extremely low, there is almost no heating of the battery even under heavy charge and discharge currents. The Concorde (and most AGM) batteries have no charge or discharge current limits.
AGM's have a very low self-discharge - from 1% to 3% per month is usual. This means that they can sit in storage for much longer periods without charging than standard batteries. The Concorde batteries can be almost fully recharged (95% or better) even after 30 days of being totally discharged.
AGM's do not have any liquid to spill, and even under severe overcharge conditions hydrogen emission is far below the 4% max specified for aircraft and enclosed spaces. The plates in AGM's are tightly packed and rigidly mounted, and will withstand shock and vibration better than any standard battery.
Even with all the advantages listed above, there is still a place for the standard flooded deep cycle battery. AGM's will cost about 1.5 to 2 times as much as flooded batteries of the same capacity. In many installations, where the batteries are set in an area where you don't have to worry about fumes or leakage, a standard or industrial deep cycle is a better economic choice. AGM batteries main advantages are no maintenance, completely sealed against fumes, Hydrogen, or leakage, non-spilling even if they are broken, and can survive most freezes. Not everyone needs these features.

the above from Deep Cycle Battery FAQ Lots of good info there, AGM is the current future if one cannot afford Lithiums as many of the new Newells, Liberty, Millinium, etc. coaches use.

I'm retired, don't need a job filling/checking battery fluid level, cleaning terminals, and battery compartment do to excessive outgassing from constant charging. We have all seen the "white mold", don't have that with the AGM's. Most wet cell banks are difficult to do maintence in large banks because of cable placement and space allowed. This can also be a dangerous labor, read the labels.
I'll stick with the AGM's and be fishing while others are cutting bait.
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Old 01-30-2012, 04:13 PM   #21
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The Batteries in my 2001 Dynasty are all the Original Interstates 4 6v Workhorse GC2 U2200 225 amp for the house and 1 8D 1400 CCA Workhorse for the Chassis. They work fine now but at their age (and mine) I plan on changing this Spring before I get one the Road rather then when I have to on the Road 12 years for Batteries is a long time. My MH has a Solar charger that maintains the Batteries when it is not being used. And has an Auto setup in the Inverter while I am using the MH. I do a lot of Boondocking (at least a couple of nites worth on our travels) between Campground plug-in stays watch the DVD and TV at night and do not conserve power I use the Generater for Microwave cooking and coffee. My refrigerator is only used on propane. This system has worked fine. I do check the water level regularly and every other year clean and neutralize the Battery trays and repaint them. In fact when I first bought this MH all the batteries were nearly dry I needed 8-9 Gallons of Distilled water since the Dealer failed to fill them while it was on the lot.
Why would I pay for another type of Battery. I don't have to ship them anywhere, I don't remove them regularly nor put them on their sides which might cause acid spills. All I would gain would be bragging rights to having the latest technology. If my Dynasty was used in rough backwoods camping where the Batteries were subjected to bouncing and off level operation I could understand. I have priced the Duracels at Sams Club and replacements will run me around $525 or so. I have a friend who is a Interstate Dealer so I might be able to get the Interstates, if they are close in price.
Why switch to some other type like AGM when these wet cells have been given me such good service. Am I misunderstanding something in this Thread.
This is all my opinion and experience.
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Old 01-31-2012, 04:53 AM   #22
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More info, hope this helps some...

AGM or Flooded batteries, but let's get into what separates these two types of batteries in actual use. AGM Batteries are maintenance free, whereas flooded batteries and the space around them require much maintenance.

AGM batteries, being sealed, will not bubble acid out while under a charge. This seal also retards 90% of the smell from the chemical reaction. There is no need to add water to the battery cells monthly, nor is there anything you must do to these batteries but charge them. Simply install your AGM batteries, charge them routinely, and forget about them. There is no clean up, no acid, and no watering to keep up with.

Flooded lead acid batteries on the other hand will smell, will excrete a mist of sulfuric acid, and may even bubble over onto their surroundings during charging and discharging. You must add water to compensate for this or the battery plates will be exposed to the air. Plates that are exposed to the air disintegrate. This acid must be cleaned routinely or any metals in the vicinity will also disintegrate. Basically, if you use flooded lead acid batteries, the money you save you are paying yourself to clean up and maintain the system. What is your time worth?

AGM is more efficient.
Based on Peukert's equations, the German scientist who mathematically solved the battery discharge problem, each battery's efficiency can be computed. AGM batteries are generally far more efficient than are flooded lead acid batteries. This is important when determining the cost to charge and discharge the batteries. Generally an AGM battery will give you between 80-90% of the power pushed into the battery, back. On the other hand, flooded lead acid batteries typically have efficiencies in the 40-60% range. The bottom lines here are time and money. Basically you spend more to charge a flooded battery than you do an AGM. This translates to money as generators eat gas, alternators rob horsepower from the engine, and battery chargers eat kilowatts. The real tragedy is that you get less of that power back from the flooded battery than you do with an AGM battery.

AGM self discharge rates are 80% - 99% better.
Batteries, being a chemical equation in flux, are not perfectly stable. A battery will self discharge as it sits. AGM batteries are far more resilient than flooded batteries when it comes to self discharge. The typical AGM battery will discharge 1 to 3% per month, with this rate remaining stable over the life of the battery. Flooded battery models do not fare as well, losing 5-10% per month when new, and up to 20 or 40% per month as they age due to antimony contamination in the negative plates.
The preceding from Comparing the AGM battery vs the Flooded Lead Acid Battery for Marine applications.

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