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Old 12-17-2013, 01:07 AM   #15
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CHECK THE DATA SHEET!

Most are full discharge at 1.75 VPC, some a little less and somr a little more.

Others have multiple points listed to show different capacities resulting in different cut off points.

Others state no equalize on AGM that is correct, it voids warranty and cause gassing which consumes the liquid stored in the mat.
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Old 12-17-2013, 08:52 AM   #16
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AGM batteries are much more expensive than flooded wet cells, and in my not very humble opinion after much research and a bit of experience, they are not better than flooded wet cells unless there is a special need.

For this reason I recommend against them.. Save your money.

True, Flooded are a bit more work, but if access is easy, not that bad.. Now if Access is an issue or if you can't mount "This side up" AGM may be indicatred (maintence free if you can mount "This side up" agm if you can not).

The "Advantages" of AGM's are really not born out by research or expierence.

What I found:

LIFELINE (brand specific) does recommend a faster initial (Bulk) charging rate than any other company.. ONLY APPLIES TO LIFELINE. This, on the average RV will make exactly NO difference in recharge time. On some it might make 20 or 30 mintues.

AGM can take a lot more physical abuse: But your RV can not.

SOME AGM's may be able to hit higher peak discharge,, But again for house batteries that is almost never an issue, if ever.

Some claim you can take an AGM down to 80% discharge (20% state of charge) but I've not seen any support for that, LIke all lead acid batteries the lower you take them the more damage you do and it is non-linier, that is the farther down the faster the damage increases.

That is research

Experience:
Got this RV in May 2005, flooded wet cells (interstate U-2200) installed, added a pair of MK AGM's in Jan of 2006, also added some maintenance free that I had lying about (2)

The first to go was... The AGM's. believe it or not, followed by first one and then the other Maintenance free (Both of which were older than the RV) and finally, This month, the U-2200's.. I'll replace them next month as I have enough MF to hold me till July.

In short the AGM's died the fastest.

Buy the way, While I was typing this I lost power (mains) the inverter (Prosine 2.0) held however. System working as designed by me.
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Old 12-17-2013, 09:31 AM   #17
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Quote:
Originally Posted by wa8yxm View Post
AGM batteries are much more expensive than flooded wet cells, and in my not very humble opinion after much research and a bit of experience, they are not better than flooded wet cells unless there is a special need.

For this reason I recommend against them.. Save your money.

True, Flooded are a bit more work, but if access is easy, not that bad.. Now if Access is an issue or if you can't mount "This side up" AGM may be indicatred (maintence free if you can mount "This side up" agm if you can not).

The "Advantages" of AGM's are really not born out by research or expierence.

What I found:

LIFELINE (brand specific) does recommend a faster initial (Bulk) charging rate than any other company.. ONLY APPLIES TO LIFELINE. This, on the average RV will make exactly NO difference in recharge time. On some it might make 20 or 30 mintues.

AGM can take a lot more physical abuse: But your RV can not.

SOME AGM's may be able to hit higher peak discharge,, But again for house batteries that is almost never an issue, if ever.

Some claim you can take an AGM down to 80% discharge (20% state of charge) but I've not seen any support for that, LIke all lead acid batteries the lower you take them the more damage you do and it is non-linier, that is the farther down the faster the damage increases.

That is research

Experience:
Got this RV in May 2005, flooded wet cells (interstate U-2200) installed, added a pair of MK AGM's in Jan of 2006, also added some maintenance free that I had lying about (2)

The first to go was... The AGM's. believe it or not, followed by first one and then the other Maintenance free (Both of which were older than the RV) and finally, This month, the U-2200's.. I'll replace them next month as I have enough MF to hold me till July.

In short the AGM's died the fastest.

Buy the way, While I was typing this I lost power (mains) the inverter (Prosine 2.0) held however. System working as designed by me.
Because your AGM's "died the fastest" does that mean that all AGM's will do the same? I think not! Be careful making such hasty generalizations.
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Old 12-17-2013, 10:20 AM   #18
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The best thing I did for filling my batteries is adding one of these. Makes it very simple adding water, especially if their had to get at.

Battery Watering Systems and Battery Tools for your RV

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Old 12-17-2013, 11:20 AM   #19
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Quote:
Originally Posted by wa8yxm View Post
AGM batteries are much more expensive than flooded wet cells, and in my not very humble opinion after much research and a bit of experience, they are not better than flooded wet cells unless there is a special need.

For this reason I recommend against them.. Save your money.

True, Flooded are a bit more work, but if access is easy, not that bad.. Now if Access is an issue or if you can't mount "This side up" AGM may be indicatred (maintence free if you can mount "This side up" agm if you can not).

The "Advantages" of AGM's are really not born out by research or expierence.

What I found:

LIFELINE (brand specific) does recommend a faster initial (Bulk) charging rate than any other company.. ONLY APPLIES TO LIFELINE. This, on the average RV will make exactly NO difference in recharge time. On some it might make 20 or 30 mintues.

AGM can take a lot more physical abuse: But your RV can not.

SOME AGM's may be able to hit higher peak discharge,, But again for house batteries that is almost never an issue, if ever.

Some claim you can take an AGM down to 80% discharge (20% state of charge) but I've not seen any support for that, LIke all lead acid batteries the lower you take them the more damage you do and it is non-linier, that is the farther down the faster the damage increases.

That is research

Experience:
Got this RV in May 2005, flooded wet cells (interstate U-2200) installed, added a pair of MK AGM's in Jan of 2006, also added some maintenance free that I had lying about (2)

The first to go was... The AGM's. believe it or not, followed by first one and then the other Maintenance free (Both of which were older than the RV) and finally, This month, the U-2200's.. I'll replace them next month as I have enough MF to hold me till July.

In short the AGM's died the fastest.

Buy the way, While I was typing this I lost power (mains) the inverter (Prosine 2.0) held however. System working as designed by me.
AGM battery failure most likely was caused/sped up by mixing/connecting other types of batteries (wet, maint free, etc) with AGM and was not recommended by my battery man. Like apples and oranges when it comes to charge and discharge ratings.
I's like mixing rechargable flash light batteries with regular alkali. It's not recommended.
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Old 12-17-2013, 12:06 PM   #20
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wa8yxm--thanks for your detailed explanation. I too have to wonder if the problems you experienced were at least partly due to the mixing of AGM vs. wet cells. I understand that my charger has two different charge settings (AGM and wet cells), and the Lifeline web page does state that there are different charging requirements. Wonder if that contributed to your results? Either way--I appreciate that you shared your thoughts and experiences. It doesn't seem a clear-cut AGM win, but I am leaning towards them for my collective pro/con eval.
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Old 12-17-2013, 05:08 PM   #21
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Regarding the 11.4 volts thing.

AGM's are just like all other lead acid batteries.

You can get AGM starting batteries and if you take them down too low.. Plan on replacement

Marine/Deep cycle,,, You might get lucky

True Deep Cycle/ Best odds of getting lucky.

However with all types of lead acid batteries.. ODDS is exactly what you get.
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Old 12-17-2013, 05:23 PM   #22
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Flooded batteries can be abused and restored agm cannot, simple as that.

When the rate of charge is high the battery creates gas thst consumes water that can be replaced in a flooded.

Agm are acid starved with no free water and pressure chamber to retsin the gas.

Agm are also VRLA or valve regulated lead acid...over charge too much and gas pressure rises to point valve opens and releases gas.

Once gone it cannot be put back.

That is why agm charging is critical to good outcome
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Old 12-17-2013, 05:38 PM   #23
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The notion that AGM's can't be recharged WAYYYYYYY faster than wet cells is comprehensively refuted with independent studies detailed here:
Charging rate

Of course...if your charger is not up to it...then you won't get the benefits...but that ain't the battery's fault. IOTA makes some great chargers for reasonable prices that you can daisy chain to keep the generator run time to a minimum.
****
NO battery of any chemistry should be taken below 12.2 or 12.0V at the Worst when AT REST with no load. False readings in the 11V range under load are NOT an at rest reading.
Keep your batts above 50% charge...and charge them to 100% when you re-charge and you will avoid killing them prematurely. The best practical tool for this is to get a REAL battery monitor....enter your bank specs and then sit back and let the monitor tell you what you need to know. (Best monitor IMO is the Victron...but others here like the Trimetric)...either way and you will save money long term AND have peace of mind.
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Old 12-17-2013, 07:00 PM   #24
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There are a lot of opinions and I prefer AGM batteries but I have relied on some of the Marine Industry for some of the information that I believe applys also to RV's. I have been very impressed with David Smead of "Ample Power" and his expertise.
Technical Documents, Manuals, App Notes
Battery Types: Flooded versus AGM and Gel
There is a terrific amount of information and you may find what you are looking for.
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Old 12-18-2013, 01:13 PM   #25
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Quote:
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Hi Guys.

I am in the market for a new set of house batteries because the ones that came with my new 40G weren't properly maintained while on the dealer lot for a full year... admitted and acknowledged by the selling dealership. The selling dealership has agreed to reimburse me for the cost of new batteries, so that's good, but given the opportunity I'd like to upgrade to AGM batteries. Of course I will pay the difference between standard coach batteries and AGM's... but here's the rub.

The RV is at a different dealership for this (and other) repairs (I live 19 hrs. away from selling dealer). They estimated $202 per battery for their "usual" RV battery. Fair enough.. When I asked for the price for AGMs, they quoted me over $400 per battery!

Now a simple Google search for AGM RV batteries by Lifeline or Trojan shows me prices from $225-$270. So is this just a dealership trying to make huge profits or am I missing something??

The dealer also said that my entire charging system would need to be reprogrammed for AGM batteries--or possibly replaced. Come on now... it's a battery that has a different medium to hold the acid. Really??

TWO QUESTIONS please:
(1) Anyone out there purchase AGM's for their house battery bank that can tell me approx what you paid??
(2) Knowledgeable members care to comment on the charger question? Is this a real concern or dealer BS?

Rob
Big AGMs are costly.
AGMs demand a different charging profile than flooded cell or FLA deep cycle batteries typically installed when the coach is new. Your inverter/charger may not provide the correct charging profile for AGMs.

I would stick with FLA deep cycle house batteries and maintain them properly.

I just installed 4 new ones in my coach @$99.00 each.
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Old 12-18-2013, 06:47 PM   #26
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I replaced the wet cells on my Journey with Duracell group 31 AGM batteries from Sam's Club. They are made by East Penn who are a well established manufacturer of mid line batteries. They were $179 each with the trade ins and have performed well to date. I had to adjust Dimensions Charger/Inverter for sealed AGM cells. I also have solar cells on the roof and configured the charge controller for AGMs as well. The big advantage of AGMs to me is not having to top up the batteries as they are not very accessible. I suspect they will not last as long as top line AGMs but they are marketed as having up to twice the life of flooded cells so time will tell.
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Old 12-18-2013, 07:39 PM   #27
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If you currently have 6V golf cart (GC2) batteries, I would stick with them unless you really want to go "maintenance free". It's tough to beat the price/performance of a 6V GC2 wet cell and, with a tiny bit of care, they last as well as AGMs with your excellent charging system.

If you have regular 12v house batteries, AGM's make a good upgrade. However, if you have a top quality 12v deep cycle like a Trojan, the AGM doesn't add much besides zero maintenance and maybe slightly faster charge time..

I disagree with the Fleetwood guy that an AGM can easily get killed by low voltage. I used them for 7+ years and find them quite hardy. Any battery is potentially harmed by a very deep discharge (anything greater than 50%), but both GC2 and AGM batteries recover well from abuse. [Just because a person works for Fleetwood doesn't necessarily make him/her expert in every possible subject.]

To answer your original question, the dealer is ripping you off on both sets of prices. I'll bet his "usual" battery is a Group 24 or Group 27 Interstate Marine (or similar) battery and those aren't worth more than $100 each, even at dealer prices and including installation. He's probably making $100 each on the batteries, no matter which you choose. I'd ask him for a credit for his standard battery (4 x $202) and go buy my own. I wouldn't be surprised if he suddenly found he could make you a better deal, since he really won't want to fork out $808 when he could put decent wet cells in for $400.
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Old 12-18-2013, 08:16 PM   #28
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just make sure there not in a bay that can get to cold i lost 2500$ of AGMs when i could not stop the cold from getting to them
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