AGM's maybe not so great???

I've just finished several hours of trouble shooting to determine that 2 of my 4 three-year old AGM batteries are goners. One is nothing more than a huge resistor and the other is a 10V battery - obviously has a dead cell.  These are Deka Group 27 12V deep-cycle AGMs dated January 2004.  Since we bought the coach in November we have no idea of its past history, but AGMs are supposed to be reliable deep cycles with a long life span and no maintenance. At $150+ each, I think I'm entitled to expect a lot more than 3 years out of them!

The symptoms of this problem were abstruse - my chassis batteries went dead!  Some research informed me that my battery controller will not charge the chassis batteries until the house batteries reach 13.3V. Mine were charging at a max of 13.1V, so the chassis batteries never got a shot and slowly discharged while the coach was sitting. Actually, it wasn't all that slow - just several days.  Took me awhile to eliminate possible problems in the controller, wiring and such, but eventually I eliminated everything. I went out and bought a good battery load tester and went through the effort to disconnect individual batteries so I could test each one and it showed that two of the batteries were definitely bad. Not just a little weak but totally bad.

Good old Trojan golf cart wet cell  batteries never gave me any such problems and they "take a lickin and keep on tickin".  Could it be that this technology is not as wonderful as we have been lead to believe? I know Ned has replaced prematurely failed AGMs. Has anyone else had this experience?

I'm pretty sure I cooked mine because the charger was overcharging them a bit too much and I wasn't cycling the batteries very often.  Lifeline did replace one under the warranty (prorated) but the other was probably my fault.  I haven't had any other reports of premature failure of AGMs, at least not any more than flooded cell batteries.  They all need some level of care and won't take abuse.

Hi Gary  We had a lot of troubles with AGM batteries when they first started using them on snowmobiles and ATV's. After doing a lot of reading I found it was the way we prepped them mostly. They have to be charged up to about 12.7 volts with a charger that only puts out 1 or 2 amps. There's a chart that comes with the batteries and in the service manual's that tells you how to check them with a digital volt meter and how long the charge needs to be. We got a Battery Tender that does 4 batteries at once and tells you when they are done. That ended the early failures. After all the reading I also found that hooking them up without a good charge didn't help them. Bombardier had a few service bulletins about battery prep also. The Yuasa website has a lot of good reading about the subject also. The other thing that impacted the life was when they started to ship them dry. They come with a funny looking container with the acid that fills it correctly. It has to be put in slowly so it can be absorbed into the mat. I sounded like you 3 or 4 years ago till I found it wasn't so much the battery. It was pretty common before to just get enough charge to get them out the door after sale. Another odd thing was that the vehicle charging system would never charge them correctly. I think if you get any more of them, a good high volume place is where to get them. There's much less chance of getting some that have sat around. Also I'd insist on a good overnight charge before you pick them up.

I bought two 6 volt AGMs at Qz in Jan '05 and they are going strong.

Of course that's only two years and maybe a total of 7 days dry camping!

Joel

I have not seen any AGM batteries that ship dry.  The only ones I've seen anywhere are sealed at the factory.  All of the AGMs I've bought came fully charged too.  Once installed the charger stayed in acceptance mode only a short while, then went to float mode.  My replacement Link 1000 has the AGM profile whereas the original one didn't.  I used the flooded cell profile and believe that contributed to the overcharging and early failure of at least one, if not two, of my AGMs.

As far as AGM batteries go I think the Jury is still out on them.  I have met a couple different folks that ended up replacing AGM batteries after three years.  Of course I have no way of knowing how these batteries were treated.  The Trojan T105/s in the Eagle are over 7 years old now and have performed flawlessly thus far.  While I expect they will require replacement within the next year or so I feel they have worked very well.  I think if I had to replace them now it would be with new Trojan batteries.  Maybe when the time comes more information reflecting better experience with AGM/s might change my mind.  I do know that if we were to get AGM batteries replacement of the link 1000 with a updated version would be required based on Ned's experience.

My Xantrex inverter/charger has the AGM charging profile and it was in use when I got it, so presumably it was factory pre-set correctly (the AGM batteries are OEM too).  And there is very little difference between the flooded cell profile and AGM profile,  no where near enough to cut life expectancy by 50% or more. We are talking a one or two tenths of a volt here.

And if a Trojan T105 died in less than 7 years I would be amazed, no matter how it was treated.

I've only owned one other AGM battery and it is still going strong at 3 years of age, so with 3 of 5 successes I guess I'm batting .600. But on T105's I'm batting 1.000 and with a quality charging system I rarely had to add water to them.

My experience with the Trojans has been similar.  Very good service from them.  Like you thet rarely need water added.

RV Roamer said:

And if a Trojan T105 died in less than 7 years I would be amazed, no matter how it was treated.

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A few years ago I had a client in Chicago area and they had taken over one of the old Western Electric facilities. When  clearing an area down in one of the basements they ran across some old lead acid batteries that were of late 1920s vintage. He said just for fun they added water and before long they were functioning!

I had same two Trojans in my gasser for 9 years  and I am going on 7 years with 4 original Trojans in my current coach and they are fine.

Wish I could say the same for my Chassis batteries! They only last a couple of years, even top of line Interstates.


Bob

My 2 house AGMs (8D) lasted 6.3 yrs.

rhmahoney said:

My 2 house AGMs (8D) lasted 6.3 yrs.

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My AGMs are 5 years and 2 months old.  Still going strong.  Maybe I should start saving some money for replacement next year.

Phil

Gary

My BIL tried AGM's on his boat and in short order pulled them and took them back for credit and went back to flooded cell batteries. He is a type A technocrat so I would assume that he set the correct charge profile.

Nelson

Looks like the usual mixed bag of battery experience here.

Mine were Deka's, a brand I have no previous experience with, so I don't know if it is a quality AGM or not.  Deka is East Penn's brand name and East Penn is one the largest battery manufacturers.  I've probably used private label batteries that were made in a Penn factory, but don't know what grade of battery they make under their own brand name. Just because a battery uses AGM technology does not mean the case and internal materials were all top of the line.

We've had Lifeline AGM batteries now for about 4 1/2 years and they appear to still be going strong. Because of the design of the early TS battery compartment door, even with a battery slide out tray it is almost impossible to monitor and refill water as needed in this dry desert climate. I haven't had to look at my AGMs since they were installed and that alone is worth the extra cost.

Gary:

      I'm not a fan of AGM's, but I love Gell Cells.  One precaution however:  Use only batteries manufactured by East Penn.  They are the best in the industry, by many experts.  My house batteries, although getting low, are now going on 9 years in service.  As Ned has mentioned, do not overcharge.

I replaced two 8D batteries on our boat with AGMs 3 years ago for a similar reason to Bernie's. When the other two wet cell 8Ds failed, I replaced them with 8D AGMs. Not enough time has passed for a verdict on any of these batteries, but I sure appreciate the lack of needing to check water due to the restricted space.

I installed 10 wet cell golf cart batteries to power the inverter and they failed at around 5.5 years. I considered alternatives for the golf carts, but chose to replace with the same type battery. I'm conscientious about checking the wet cells, irrespective of whether or not we use the boat (they're much easier to get at than the 8Ds).

A friend had eight Trojan L-16 batteries on his boat, but he wasn't conscientious about checking water levels. They failed prematurely. L-16s have the same footprint as a golf cart battery, but are much taller and have a correspondingly higher capacity and higher price.

Any battery will die prematurely if abused.  Abuse can be overcharging, not keeping the electrolyte level up (not a problem in AMGs), too deeply discharging, or applying excessive loads.  A common saying in the battery industry is most batteries don't die, they're killed.

Ned said:

Any battery will die prematurely if abused.  Abuse can be overcharging, not keeping the electrolyte level up (not a problem in AMGs), too deeply discharging, or applying excessive loads.  A common saying in the battery industry is most batteries don't die, they're killed.

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Unless they are made by Excide. IMHO ;D

Ned said:

Any battery will die prematurely if abused.

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You're right Ned and I thought I implied that in the case of my friend's Trojans. I reported the episode in a lot more detail in an earlier post, but figured I didn't need to repeat it all.

Mine was a general comment, not specifically about your incidents.  The reports of both long lived and premature failures of all types of batteries bears it out.