AGM batteries - are they better?

[DryCamper11]

Upgrade to an AGM battery. You can safely mount them inside, and upside down, and they will out-perform any flooded battery you ever owned!

Here's a quote from another thread. It's typical of others I've seen. I wonder if anyone here can convince me it's correct. Clearly the AGM has some advantages. Two are seen in that quote - inside and upside down. If you need to mount upside down and can't ventilate, sure, that's an advantage, but I don't need those advantages and don't want to pay extra for something I don't need.

We're left with the rapid charge rate they are reputed to permit. I would love to run my 80A charger at 80A continuously until I reach 100% SOC. Right now my 460AH FLA batteries recharge at 80A from 50% SOC for about 3 hours (some fluctuation in current - slow climb from below 80 to above 80 during the first hour as they warm up then down to 70+ at the third hour), then begin to taper more rapidly during the last hour as the battery voltage approaches the charger voltage.

Does anyone have charge curves for AGM showing the performance (preferably with an 80A charger)? I'd particularly like to see the tail end of the charge cycle. How do AGMs perform? Is it significantly better than FLA batteries? Do AGMs taper the charge rate the way FLAs do, or is the entire advantage in the fact that I could run a bigger charger (100+ A) for my 460AH battery bank?

Are there other advantages that AGMs offer?

[Wayne_Dohnal]

My guess is maybe 20 people here have AGM's, that's 40 batteries tops (extreme WAG but I don't think I'm too far off).

I've got an even dozen. Who has the other 28?

[mena661]

crosscheck wrote:
In my situation, I required AGM's and I am happy after 3 years of fairly heavy use.

After reading about how many people have replace their existing wet's with AGM's on this forum, I still wonder why at almost twice the price this would be the case?

The AGM market is very tiny. Most people here have 1 or 2 batteries tops. My guess is maybe 20 people here have AGM's, that's 40 batteries tops (extreme WAG but I don't think I'm too far off). That's not going to do anything to lower AGM pricing. Golf courses buy batteries by the 1000's. That's where the sales are and why GC's in particular are so cheap and why there's so many available. They also get the most R&D because they're used so much. Golf courses and the off grid market. The off grid market is relatively small too but those people spend LOTS of money on their batteries so they get some R&D/lower cost love too.

[BFL13]

I would think that the battery price would depend more on shipping costs for where you buy them. If the place is at a railway siding and can carry lots of batteries it should be cheaper there than at a place off in the boonies that only carries a few batteries and has to pay extra shipping to get those from the guy at the railway siding.

Big thing here is taxes and fees. Store at the mall has to pay high rent for its space plus high town taxes, but may have high volume to lower unit cost. Store out of town has lower taxes, no mall space rental. But low volume so higher unit cost to you. It is a mug's game. Shop till you drop before buying.

[Almot]

full_mosey wrote:

When I bought my Bass-Pro re-badged Deka 79AH AGM in Jan 2009 for full retail of $165 that represented $2.09/AH. Today a 100AH re-badged Deka At Sam's Club is $180 or $1.80/AH. That IS less!

I wrote about same model today and 10 years ago, not $/AH cost between different sizes. Lead prices TRIPLED in the last 10 years, from $0.3 to $0.9: Here.

[crosscheck]

In my situation, I required AGM's and I am happy after 3 years of fairly heavy use.

After reading about how many people have replace their existing wet's with AGM's on this forum, I still wonder why at almost twice the price this would be the case?

Remember,these are the some of the same guys who have as much time as Methuselah,will drive 20 miles across town to save 10cent/gal. on diesel, know to the penny the different prices for TP at Walmart and are watching that big life savings pile of chips diminish. They don't part with money easily.

And others on this thread have said, "Why are you buying a Mercedes for twice the price when a Yugo can perform as well or better?":)

Dave

[full_mosey]

Almot wrote:
The trend of FLA getting more expensive ...
AGM are getting more expensive too....

It should be clear that the opportunity to acquire AGMs at better prices is a reality.

When I bought my Bass-Pro re-badged Deka 79AH AGM in Jan 2009 for full retail of $165 that represented $2.09/AH. Today a 100AH re-badged Deka At Sam's Club is $180 or $1.80/AH. That IS less!

I would guess that a 6V GC at Sam's was $65 then and they are now $85. That IS more!

HTH;
John

[full_mosey]

msiminoff wrote:

I think Deka makes very high quality batteries! That said, That Deka Gp34M battery is rated at 55Ah, 775CCA, and weighs 42.5lbs.
The Odyssey PC1400 (Platinum Gp34) is rated at 68Ah, 880CCA, and weighs 49.5lbs

Thanks for correcting me on those specs.

Funny that the Sears/Deka AH/lbs ratio compares almost exactly to the Optima 55AH at 43.5lbs. I would choose the Deka over the Optima for RVing.

I do have the 68AH Sears P-4/Odyssey PC1400 as the starting battery in my van. It cost $165 on sale in Oct 2012. Enersys(Odyssey) is also a great mfgr.

HTH;
John

[Almot]

The trend of FLA getting more expensive is the result of shortage of all kind of raw materials in the last decade or so. Rapidly growing economy and population of already over-populated China and India are the main factors. This will not stop - not their population growth anyway - and metals will become more and more expensive.

AGM are getting more expensive too. There are occasional discounts due to re-badging, including re-badging after selling the brand and/or moving the manufacturing to China (ex. Panasonic became UPG) but the trend is still the same, more expensive metal = more expensive batteries. Look at the prices of any given model today and 10 years ago and you will see.

[msiminoff]

landyacht318 wrote:
Anybody look into these sear die hard Advanced Gold AGM batteries?

Those do appear to be re-badged Deka AGM' and at the $123 sale price they're a good buy! But IMHO, if I were buying AGM batteries at Sears I'd spend the extra $$ to get the Platinum's in a Group 31 size (assuming they'll fit). They are manufactured by EnerSys and identical to the Odyssey line of batteries.

full_mosey wrote:
I like the Gold/Deka spec better than the Platinum/Enersys. It should have 79AH rating where the Platinum is by Enersys(Oddysey) and only has 68AH for the same weight.

I think Deka makes very high quality batteries! That said, That Deka Gp34M battery is rated at 55Ah, 775CCA, and weighs 42.5lbs.
The Odyssey PC1400 (Platinum Gp34) is rated at 68Ah, 880CCA, and weighs 49.5lbs

[full_mosey]

mena661 wrote:
Another good deal on AGMs and these are easily found too.

I paid $314 for 2x55AH=110AH Optimas in Jan 2010, now four years later, I can get 2x100AH =200AH Sam's Club for $360. This trend is good because FLA prices are higher now where AGM prices are lower than 2010's along with more choices and availability. Amazing!

More R in RV.

HTH;
John

[mena661]

full_mosey wrote:

I would say yes. Deka. The case is identical to the Automotive style.

And on sale for Group Size 34R $123.74, good price. I like the Gold/Deka spec better than the Platinum/Enersys. It should have 79AH rating where the Platinum is by Enersys(Oddysey) and only has 68AH for the same weight.

Another good deal on AGMs and these are easily found too.

[full_mosey]

landyacht318 wrote:
Anybody look into these sear die hard Advanced Gold AGM batteries?

I would say yes. Deka. The case is identical to the Automotive style.

And on sale for Group Size 34R $123.74, good price. I like the Gold/Deka spec better than the Platinum/Enersys. It should have 79AH rating where the Platinum is by Enersys(Oddysey) and only has 68AH for the same weight.

I have an 8A24M with BassPro decals.

That's the battery I tested at 100% of C20 ~78A(900W inverter load) for 7 minutes. Two of those might run a microwave for a while.

HTH;
John

[landyacht318]

Anybody look into these sear die hard Advanced Gold AGM batteries? Looks like a rebadged Deka Intimidator and the prices are not so excessive and about 50 bucks less than the platinum/ odyssey.

I am thinking bout replacing all my batteries 2 house 1 engine, with these. I have been guilty of letting my flooded batteries get low killing one 2 year old set and compromising the other to the point where I don;t expect 2 years of nightly cycling from them.

[Almot]

MEXICOWANDERER wrote:
Reminds me of the "Ugly but sure can cook, baby" analogy.

🙂 this is why I ignored this thread for the first 6 pages. Too many variables.

[Almot]

... pay the extra money on AGMs to get that extra couple of minutes of quiet time.

Personally, if I was in that concerned with generator noise I would be camping in places with electric hookups. After all whats the point of dragging a long a big expensive RV out into the wilderness with a big screen, DVD/Blue ray, surround system, PC, cell phones, game system and any other electronic gadget if you are not willing to put up with a generator for a few hrs per day?

A lot of people are not willing to put up with a generator, so they don't drag all their shore life toys out into wilderness. Believe it or not, being warm and fed often can be enough to feel well. For an adult person, anyway.

Back to the point - I agree that very few AGM have extremely high charge acceptance rate. Lifeline has 5C max rate. Still, most other AGM have 0.3C.
Flooded - I don't know, seems that nobody cares :), though Trojan recommends 0.1C-0.13C. This is ~2.5 times slower than average AGM, so this is not "minutes". But, like I said, nobody cares about exceeding those rates with flooded, especially weekend warriors, their GC will last many years no matter what rate.

To me the advantages of AGM is the ability to keep them inside, like under-bed storage, and the ability to store for 8-10 months or longer - depending on temperature - without maintainer. Flooded would drop below 40% in 6 months. The watering-free feature of AGM is incidental to me. When you have to store it for more then 6 months without being able to check it, this means that there is no watering or any other maintenance, with or without 120V maintainer, because you don't know if maintainer even works during that time.