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Discussion Starter #1
Recently had some slow cranking problems accompanied by numerous service prompts on the evic. Additionally, the wipers started flapping for no reason & once the shift knob was locked in park & couldn't shift it. I'm sure all these maladies were the results of the various sensors being starved for adequate voltage & sending false alarms to the ecu. I was concerned that something was draining the batt & dreaded the vicious cycle of trial & error attempts to rectify it by the service dept. carried it to the shop yesterday & the good news was the battery tested defective. The bad news was they didn't have one. They offered to fetch one from a dealer in an adjoining town & it would take a couple of hours if I'd like to wait. I consented & the 2 hr wait turned into 4. After a miserable total of 6 1/2 hr wait I had a new batt & was on my way. Something even more concerning to me is the fact that our batteries are actually agm's rather than wet cell. Agm's have been around for a long while & are excellent batteries in the right environment. Their use has been primarily limited to rv house batteries, golf carts & marine applications but this is the first time I've seen it used in an engine compartment from the factory. These batteries are infamously susceptible to damage due to exposure to heat. Unless things have changed in the last 5 years, excessive heat could cause malfunction & possible damage. One manufacturer recommended charging be halted if temps exceeded 120 degrees!! Why in the world is this batt living beside a diesel engine?? I can't imagine that mama chrysler thinks that cheesy little blanket is going to be an adequate safeguard. I found this info when searching for an rv house batt about 4 years ago. If we've got a batt guru on board that knows of improvements on the heat issue of the agm please chime in.
 

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Friend in Georgia works selling batteries. He took one look at my battery and said something like ..."Mercedes Type 96" or something like that.


Immediately he told me it was generically called a Mercedes battery as they were designed for their diesels to run on a single battery.


Do know you are not the only one that had battery issues. Thanks for the info.
 

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Is it possible to swap AGM to Wet Cell, or is being AGM integral to the diesel?
The AGM vs Wet is just the make up of the battery. The AGM is better at handling vibration among other things. It's used in the marine industry a lot.

As long as you have cranking amps you need, you can swap between the two. In my opinion the AGM is a much better battery, it's definitely more expensive if you went out to buy one so it's worth forcing the dealer to replace it if you have a bad one. Once it fails when you are out of warranty you may want the cheaper wet cell.
 

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The AGM vs Wet is just the make up of the battery. The AGM is better at handling vibration among other things. It's used in the marine industry a lot.

As long as you have cranking amps you need, you can swap between the two. In my opinion the AGM is a much better battery, it's definitely more expensive if you went out to buy one so it's worth forcing the dealer to replace it if you have a bad one. Once it fails when you are out of warranty you may want the cheaper wet cell.
oh interesting, what about the heat vulnerability?
 

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The AGM vs Wet is just the make up of the battery. The AGM is better at handling vibration among other things. It's used in the marine industry a lot.

As long as you have cranking amps you need, you can swap between the two. In my opinion the AGM is a much better battery, it's definitely more expensive if you went out to buy one so it's worth forcing the dealer to replace it if you have a bad one. Once it fails when you are out of warranty you may want the cheaper wet cell.


You could replace the AGM with a flooded lead acid battery, as long as you have enough CCA, which would most likely require a physically larger battery.


Replacing a flooded lead acid battery with an AGM could ruin the battery. "As with all gelled and sealed units, AGM batteries are sensitive to overcharging. These batteries can be charged to 2.40V/cell (and higher) without problem; however, the float charge should be reduced to between 2.25 and 2.30V/cell (summer temperatures may require lower voltages). Automotive charging systems for flooded lead acid often have a fixed float voltage setting of 14.40V (2.40V/cell), and a direct replacement with a sealed unit could spell trouble by exposing the battery to undue overcharge on a long drive."
 

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Discussion Starter #8
"It was furthermore noticed that exposing the batteries to temperatures above 40°C (104°F) could cause a thermal runaway condition due to dry-out."

An observation of some lab tests conducted by an organization called Battery University when testing agm batteries. Not sure what a thermal runaway is but doesn't sound good. Cohabitation with a Diesel engine seems a very questionable environment for this type battery but I'm sure the the renowned engineers at chrysler know what theyre doing ( ahhh maybe?).
 

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The AGM battery is really sensitive to temperature in both directions.
One manufacturer of AGM batteries, Lifeline Batteries, states the following.


"Battery capacity is also affected by temperature. As a rule of thumb, the battery life decreases by 50% for every 10C rise in temperature. Thus, a battery that lasts 6 years at 25C will last 3 years at 35C, etc."


"Battery capacity is reduced significantly in cold temperatures. For example, a battery that operates continuously at -18C will only provide about 60% of its normal room temperature capacity."


Our Canadian friends may not like this last "feature".
 

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Replacing a flooded lead acid battery with an AGM could ruin the battery. "As with all gelled and sealed units, AGM batteries are sensitive to overcharging. These batteries can be charged to 2.40V/cell (and higher) without problem; however, the float charge should be reduced to between 2.25 and 2.30V/cell (summer temperatures may require lower voltages). Automotive charging systems for flooded lead acid often have a fixed float voltage setting of 14.40V (2.40V/cell), and a direct replacement with a sealed unit could spell trouble by exposing the battery to undue overcharge on a long drive."
I never thought about the charging system. The one on my boat can handle both. This note cautionary note talks about replacing an acid battery with an AGM and having problems, we're talking the other way around.
 

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I have a lot of faith in AGM batteries.

I have one in my OLD single cylinder vibration machine, called a Royal Enfield. AGM lasts way longer than flooded lead batteries in that old washing machine.
 

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Just a suspicion here, but it "may not" be a battery problem.
I know little about the ecoDiesel version, but I seem to
remember that the battery in some of these trucks is located
over the axle.

For some reason, I seem to remember that is just a bad
idea for batteries in general.

Stated differently, there is a reason why every vehicle I've
owned going back to a 67MY unit always had the
battery either on the left or right side behind the radiator
support beams.
 

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Just a suspicion here, but it "may not" be a battery problem.
I know little about the ecoDiesel version, but I seem to
remember that the battery in some of these trucks is located
over the axle.

For some reason, I seem to remember that is just a bad
idea for batteries in general.

Stated differently, there is a reason why every vehicle I've
owned going back to a 67MY unit always had the
battery either on the left or right side behind the radiator
support beams.
It's in the engine compartment, same as any modern truck.
 

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Just a suspicion here, but it "may not" be a battery problem.
I know little about the ecoDiesel version, but I seem to
remember that the battery in some of these trucks is located
over the axle.

For some reason, I seem to remember that is just a bad
idea for batteries in general.

Stated differently, there is a reason why every vehicle I've
owned going back to a 67MY unit always had the
battery either on the left or right side behind the radiator
support beams.
The ecodiesel is the same, to the side, but up by the radiator. Do you own one, or are you just making stuff up?
 

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The ecodiesel is the same, to the side, but up by the radiator. Do you own one, or are you just making stuff up?
Don't own ... am studying...

Oh and this is the Pentastar engine in a RAM... that would be a battery over the driver side wheel??? ...;


 

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And to stay ON topic, this is the ecoDiesel.

Again, battery clearly mounted over the driver side wheel
and nowhere near the radiator support beams...


 
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