AGM battery questions

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gold68dart

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Need a new battery for the Dart and am considering an AGM battery but...

1. Are they worth the $$?
2. If so, there are a bunch out there each with different and inconsistent reviews...Exide, Deka, Diehard, Odessey, Optima, Duralast, etc. Which ones are you guys running?
3. More importantly to me is will acid still build up on the terminals as in lead acid batteries? Would be great to not have to worry about acid getting on the paint. The alternator on my brothers Duster overcharged his battery, it boiled over and acid ended up staining the paint in his engine compartment.
 
Frankly, regardless of the type of battery, you should resolve the overcharge condition. This is a VERY prevalent problem, and often fairly easy to correct. The main causes of overcharge are:

1...MOST of the time, voltage drop in the ignition harness. I've posted extensively on this problem. This, basically, is where the VR IGN terminal, which is the "sense" and power connection, is "seeing" less than "what the battery is." The VR "thinks" the battery is low and ramps up voltage

2....Sometimes, same problem as above in the ground circuit. The VR MUST be grounded TO the "same as" battery negative.

3...Fairly uncommon is a VR that is "out of spec" so far as voltage

4...Last is a battery that has been damaged, either a cell that is damaged, or sulphated because of undercharge or stored while undercharged
 
67Dart273 said:
Frankly, regardless of the type of battery, you should resolve the overcharge condition. This is a VERY prevalent problem, and often fairly easy to correct. The main causes of overcharge are:

1...MOST of the time, voltage drop in the ignition harness. I've posted extensively on this problem. This, basically, is where the VR IGN terminal, which is the "sense" and power connection, is "seeing" less than "what the battery is." The VR "thinks" the battery is low and ramps up voltage

2....Sometimes, same problem as above in the ground circuit. The VR MUST be grounded TO the "same as" battery negative.

3...Fairly uncommon is a VR that is "out of spec" so far as voltage

4...Last is a battery that has been damaged, either a cell that is damaged, or sulphated because of undercharge or stored while undercharged
Click to expand...


Overcharging will kill an AGM in a hurry.
 
Thanks guys. Fortunately I don't have overcharging issues but my brother fixed his. I'm just wondering if you still can get acid buildup on the terminals of an AGM battery. Also looking for opinions on which are the better AGM batteries.
 
I've never had any corrosion/acid issues with an AGM battery. I've used Optima, Odyssey and DieHard. The DieHard Platinum are re-labeled Odyssey, but less expensive.
 
Have had Yellowtop Optima's in three different rides and have never had acid buildup on any of them. My 1st one still in use has lasted over 11 years just in my possession and was already in a car I purchased.I had never kept it on a trickle charger but last year when it got weak I started keeping them all on the trickle. Before getting another new one last year I read all the reviews and folks were down on them stating they weren't made as good anymore but I bought one anyway so we shall see. They were a helluva lot cheaper then the Odyssey's.
 
Im using optima blue top, good reserve and CCA . they don't leak. IMO best battery money can buy. MT
 
AGM batteries have a different charging and float voltage profiles than a flooded lead acid battery. There are special regulators for use with AGM, a standard regulator will overcharge.
 
KitCarlson said:
AGM batteries have a different charging and float voltage profiles than a flooded lead acid battery. There are special regulators for use with AGM, a standard regulator will overcharge.
Click to expand...

NEWS to me! Have to check that out. MT
 
My yellowtop has been going strong for 14plus years. Starts the car every spring after being stored outside in the trunk, at up to -35*C.
Its been;overcharged, under charged, and drained to near death. It doesnt outgas, leak, corrode, or talk back to me. Its never cost me a tow-call, or left me stranded anywhere.Its seen at least two alternators, and three regulators.Stone-age reliable
Its been flat-out the cheapest battery I have ever owned.
 
I believe there is a special charging procedure on AGM type batteries, something like charging them in series with a regular battery? I thikn thats when they are dead flat and need to be "woken up"

"....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. See Charging Lead Acid.

AGM and other sealed batteries do not like heat and should be installed away from the engine compartment. Manufacturers recommend halting charge if the battery core reaches 49°C (120°F). While regular lead acid batteries need a topping charge every six months to prevent the buildup of sulfation, AGM batteries are less prone to this and can sit in storage for longer before a charge becomes necessary. Table 1 spells out the advantages and limitations of AGM...."
 
A standard regulator is constant voltage, there is some temperature compensation, but it does not monitor battery temperature directly, nor cut back voltage enough. Too high of float voltage dries out the electrolyte. It is easy to hit elevated temperatures underhood, where the float voltage needs to be significantly reduced, even to 12V.

http://www.google.com/imgres?imgurl...lient=tablet-android-samsung&ved=0CB8QMygBMAE
http://www.google.com/imgres?imgurl...lient=tablet-android-samsung&ved=0CBwQMygAMAA
 
I guess this would be a good place to post this since it's all related.

Don't trust the "smart" battery chargers that tell you to service or replace the battery. I have a Black & Decker 10 amp charger which has worked well charging between rounds and at home for a few years now. I went to charge my race car battery like I do periodically to top it off. It told me to service or replace the battery. (It worked fine the previous weekend at a race.) I put it on my trailer battery and it said the same thing. I put the charger on a brand new battery and it was fine, and fully charged. (I got depressed at the thought of having to a new battery or two.)

Still suspicious that something wasn't right, I put it on a third used but fully charged battery and it also said to service or replace it! Since I'm obsessed with having spare parts & equipment, when possible, I had a spare new charger just like it. It read and charged fine on all of the batteries I tried before!

* I figure that there is a sensitive sensor in the used battery charger that was malfunctioning. So double & triple check your batteries, if at all possible, before believing a "smart" battery charger.

These were all AGM batteries - used Odyssey & 2 Optimas and a new Sears Die Hard Platinum.
 
Smart chargers rely on good terminal connections. That can be iffy with clamps trying to go outside of battery cable terminals with battery installed. Smart chargers often come with ring lugs and connectors for ease of reliable connections.

Smart chargers rely on transient impedance tests, and also monitor how the battery responds to charge current over time. Since chargers are often multi use for a range of battery sizes, tests are not always certain. Measuring battery open circuit potential after charging, and load test are good in most cases.
 
Locomotion said:
I guess this would be a good place to post this since it's all related.

Don't trust the "smart" battery chargers that tell you to service or replace the battery. I have a Black & Decker 10 amp charger which has worked well charging between rounds and at home for a few years now. I went to charge my race car battery like I do periodically to top it off. It told me to service or replace the battery. (It worked fine the previous weekend at a race.) I put it on my trailer battery and it said the same thing. I put the charger on a brand new battery and it was fine, and fully charged. (I got depressed at the thought of having to a new battery or two.)

Still suspicious that something wasn't right, I put it on a third used but fully charged battery and it also said to service or replace it! Since I'm obsessed with having spare parts & equipment, when possible, I had a spare new charger just like it. It read and charged fine on all of the batteries I tried before!

* I figure that there is a sensitive sensor in the used battery charger that was malfunctioning. So double & triple check your batteries, if at all possible, before believing a "smart" battery charger.

These were all AGM batteries - used Odyssey & 2 Optimas and a new Sears Die Hard Platinum.
Click to expand...


I had the same sort of issue's with a smart charger and found that the connections at the clamps were just crimped on.
Once I soldered those connections it straightened up and has been fine ever since.

It serves to agree with what others said about the connections with smart chargers.
 
Thanks guys. I'll make more secure connections & see if that helps. hopefully all this will help other "smart charger" users as well. Thanks again.
 
Clamps are already soldered to the wires, so unless there are some broken wires in between, the issue may be internal. Interestingly, when the used batteries are fully charged, the malfunctioning old charger shows everything ok and goes into trickle charge! :scratch:
 
The Sears diehard platinum is an Odyssey


Sears will put the battery on sale occasionally, so you can get them cheaper than the equivalent Odyssey.
 
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