your stock battery should last 6-10 years

 

Finally , some one around here with a sense of humor

 

Maybe it depends on climate, but here in South Dakota I have had failures after 2 years, don't trust them much after 3 years, and pro-actively replace them at 4 years in the unlikely event that they last that long. Doesn't seem to matter whether they are factory or aftermarket such as Diehard.

 

THE 2011 GRAND CHEROKEE and Durango USES ABSORBENT GLASS MAT (AGM) BATTERY TECHNOLOGY

An AGM battery is a sealed unit that uses special relief valves to vent vapors from the battery. The electrolyte is stored in sponge like separators consisting of matted glass filters. This suspension increases the efficiency of the charging and discharging rate of the battery. Continuous under and overcharging is detrimental to this type of battery, therefore; voltage and current regulation are critical.

Typical battery chargers ARE NOT SUITABLE as the voltage and current regulation ranges of typical battery chargers are unsafe for AGM batteries.

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.

 

Good info! I do have one question from reading your post. It says a that typical battery chargers are not suitable, but the third to last paragraph says there is no need for any special adjustments or problems with incompatible chargers or charge controls, what gives?

 

Huh - never heard that before. It will be interesting to see how long they really last but sounds like they've overcome many of the problems of the standard battery. Sounds like replacement won't be cheap, but as I put 25k+ miles on per year, maybe I'll never have to replace it before I trade it off around 150k.

 

Thanks for the info guys , that explains why there's a tube that goes into the top of the battery.I

 

Will diffinitely look for AGM types .

 

Looking at the wiki page for VRLA batteries, which are the family to which AGM batteries belong, it claims that AGM batteries can be less reliable and have a shorter lifetime than a "properly maintained" flooded lead/acid battery, though "properly maintained" is left unspecified.