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I was looking to Upgrade to a New AGM Battery in my 85 Trans Am. AC Delco Makes AGM Batteries, but does not show as a fit for my car. Typically I like the stock GM Battery look, but the AGM Batteries offer alot advantages over the Acid Filled Batteries. Not looking at Optima Batteries since the reviews are not good and surely does not appear stock.
Found a couple of AGM Batteries that is an exact Fit from Autozone and Advanced Auto parts, any one have one of these Batteries in thie Third Gen ? Part listed is 75-AGM for the Side Post Model for $194. So was thinking of buying one and slap on one of those GM Delco Freedom Sticker on Top of it to appear stock looking.
I am open to any recommendations on any Brand of AGM for our cars.
I had an Optima red top in my 88 for 10 years no problem. When it finally died it died...just like a regular battery. I bought another.
Having said that, there is something to be said for a factory look. And if Delco is offering them, that's good.
The only thing I would add is that a regular battery charger won't work on an any AGM battery that is drained significantly. I think anything below a 25% charge.
I agree, Optimas suck since they started making them in Mexico. I have had friends not make it through the warranty period with them.
I like the AGMs. I have them for all my vehicles now. No worries on charging them either, you just really can't do high amp charges since you will outgas too much and it will force it to let gas out of the pressure relief with the rapid charging.
I have been buying East Penn/Deka batteries, I would say give that one a shot
I had an Optima red top in my 88 for 10 years no problem. When it finally died it died...just like a regular battery. I bought another.
Having said that, there is something to be said for a factory look. And if Delco is offering them, that's good.
The only thing I would add is that a regular battery charger won't work on an any AGM battery that is drained significantly. I think anything below a 25% charge.
Thanks for the info, will check East Penn/Deka batteries out for sure. Normally just use a Battery Tender to keep the batter fully charged when TA is not in use.
Thanks
Last edited by 1985blktransam; 04-17-2019 at 02:43 PM.
Reason: missed something
I tried AGM batts. IMHO, they are not really better than good regular batteries and when they go dead, they go DEAD. They need to be charged with chargers that recognize AGM batteries or else they may not charge up.
the only place where an agm shines and is practical in northern climates where the cca can be utilized and imo I don't see the point for the cost over a traditional lead/acid battery.
The best AGM on the market is the Odyssey Performance or Extreme series. I have them on both my cars. They are a deep cycle, fast charge product if properly taken care of they can last 10 years. Go on the Enersys Battery website to see the features & benefits over typical lead acid or other AGM products on the market.
They need to be charged with chargers that recognize AGM batteries or else they may not charge up.
Not true. An alternator doesn't know, or care what battery is connected. Floating a charged battery is floating, they are all the same voltage.
Originally Posted by SUPER CHEVY66
the only place where an agm shines and is practical in northern climates where the cca can be utilized and imo I don't see the point for the cost over a traditional lead/acid battery.
Well for one, you don't get corroded terminals like a traditional flooded wet cell. I don't see much of a price difference to be honest, maybe $30 at most? I am buying Penn East, not an overpriced POS like an Optima though.
The only case would be a deeply discharged, but if the battery is charged, float is float. And the video doesn't actually negate anything I said, charged is charged.
No special info in the video. They just want to sell you a charger for their crap product.
I had an old USA made Optima way back and it was AWESOME. I KILLED it twice, and froze it twice when it was dead. I think it was like 2 volts when I put it on the charger. Twice it came back to life before it finally died, like 8 or 9 years old. Now they don't even always make it through the warranty period
The only real difference with an AGM battery is you don't want to charge too fast, or too high a voltage, or you let too much gas escape the pressure relief and it can't combine back into the electrolyte. Other than that, there isn't really any difference to the operation or charging. LIke I said, the alternator doesn't know, or care, what type of battery is connected, so "special" chargers are total marketing ploys.
The only case would be a deeply discharged, but if the battery is charged, float is float.
No special info in the video. They just want to sell you a charger for their crap product.
I had an old USA made Optima way back and it was AWESOME. I KILLED it twice, and froze it twice when it was dead. I think it was like 2 volts when I put it on the charger. Twice it came back to life before it finally died, like 8 or 9 years old. Now they don't even always make it through the warranty period
The only real difference with an AGM battery is you don't want to charge too fast, or too high a voltage, or you let too much gas escape the pressure relief and it can't combine back into the electrolyte. Other than that, there isn't really any difference to the operation or charging. LIke I said, the alternator doesn't know, or care, what type of battery is connected, so "special" chargers are total marketing ploys.
Scooter - the some of the new fully "digital" battery chargers produce a voltage that "looks" different (to the battery) than the voltage produced by an alternator in the car.
it can make for charging issues. AGM batteries started being used in aircraft before they gained widespread popularity in the automotive world and I have seen some of the older battery chargers
that simply wont charge an AGM batter properly, the key word here is PROPERLY, this has been my experience anyway
Scooter - the some of the new fully "digital" battery chargers produce a voltage that "looks" different (to the battery) than the voltage produced by an alternator in the car.
it can make for charging issues. AGM batteries started being used in aircraft before they gained widespread popularity in the automotive world and I have seen some of the older battery chargers
that simply wont charge an AGM batter properly, the key word here is PROPERLY, this has been my experience anyway
I am aware that some chargers won't start charging a low battery, and why they said in the video to "jump" it to a good battery, which "brings up" the voltage on the low battery, again not new info. You can also try to "jump start" a dead battery by just supplying OVER voltage to the cell to "wake it up" and take a charge, sometimes. (can be dangerous, not recommended)
Aircraft is something I am not familiar with, but I would wager that they are rectifying AC to output DC to charge batteries, just like a car and for the purpose of this discussion aircraft is irrelevant.
The only real difference here is that Optima batteries are AGM AND spiral cell, but generally an AGM isn't really different INSIDE the battery than a flooded wet cell, except it really just has the absorbent gas mat to recover the separated Hydrogen and oxygen during the charging cycle and then allows them to combine back into water to supply the battery. There isn't anything special about the construction other than the AGM part, it's just a lead acid battery. In a car, neither the battery nor the alternator know what the other is, they just put out voltage.
I don't G.A.S. about digital charger marketing ploys to sell you something you don't need to make up for a POS battery. Once the battery is "charged" floating the battery so it it's charging is the same for any type of lead acid. You don't want to be constantly charging it and you don't want the voltage to drop, it's pretty simple.
I am aware that some chargers won't start charging a low battery, and why they said in the video to "jump" it to a good battery, which "brings up" the voltage on the low battery, again not new info. You can also try to "jump start" a dead battery by just supplying OVER voltage to the cell to "wake it up" and take a charge, sometimes. (can be dangerous, not recommended)
Aircraft is something I am not familiar with, but I would wager that they are rectifying AC to output DC to charge batteries, just like a car and for the purpose of this discussion aircraft is irrelevant.
The only real difference here is that Optima batteries are AGM AND spiral cell, but generally an AGM isn't really different INSIDE the battery than a flooded wet cell, except it really just has the absorbent gas mat to recover the separated Hydrogen and oxygen during the charging cycle and then allows them to combine back into water to supply the battery. There isn't anything special about the construction other than the AGM part, it's just a lead acid battery. In a car, neither the battery nor the alternator know what the other is, they just put out voltage.
I don't G.A.S. about digital charger marketing ploys to sell you something you don't need to make up for a POS battery. Once the battery is "charged" floating the battery so it it's charging is the same for any type of lead acid. You don't want to be constantly charging it and you don't want the voltage to drop, it's pretty simple.
I've been to several of the big battery manufacturers training classes for Aviation batteries and have 35 years in the maintenance and up keep of Lead Acid, AGM & Nicad batteries......but I bow to your expertise on this matter sir !!
You are the first battery "expert" I've come across....thanks, I appreciate the assistance
This pretty much says everything I posted. The "float" voltage on an AGM and Gell is slightly lower, per cell, than a flooded wet cell, but not by much.
This pretty much says everything I posted. The "float" voltage on an AGM and Gell is slightly lower, per cell, than a flooded wet cell, but not by much.
This is a quote from the document you supplied in your last post......the link above........
"Therefore, it is critical that a charger be used that limits voltage. The charger must be temperature-compensated to prevent underor overcharging due to ambient temperature changes. (See Charging Voltage vs. Ambient Temperature chart on page 11.) Important Charging Instructions The warranty is void if improperly charged. Use a good constant potential, temperature-compensated, voltage-regulated charger.Constant current chargers should never be used on VRLA batteries"
What I have been trying to tell you is these batteries are sensitive to a specific type of charger, many older chargers are constant current chargers that can damage these batteries. Do yourself a favor an follow manufacturers recommendations. Unless you were the engineer that designed the product you dont know what you dont know !!!
I bought an Optima yellow top in 95, and it lasted almost 10 years... had a Battery Tender on it, it lasted 10+....
But then I started seeing bad reviews on Optima... There is a thread here on Thirdgen.... I went to cheaper batteries, that seemed to last about 2 years (Florida)....
Last round, I bought a Odyssey battery, a bit pricey, it is AGM, also has thinner lead plates which equals more surface area, deep cycle, etc.... It is a few lbs heavier than the "stock" replacement. But many people have gotten 10 years from them... I bought a CTek charger which has more LED's to let you know what state of charge the battery is in, 8 steps I believe. I think it monitors temperature and also does stop charging to let it drop a little, so no constant charge. It does have a 4 mode options, car / motorcycle, SLA or AGM and a Recovery Mode... I think it was $65
So far so good, but it's only been 6 months
Dont know if one of these people posting here works for Optima or not. Anyhoo. I never had issues with Interstate brand batteries in many cars..That said. I run a battery in the trunk and use an Optima. I had an issue with one years ago that was not that old and died and could not bring it back. Use a charger that specifically has an agm setting. I'm agreeing that there should be a difference in the charging aspect of agm vs regular or the option would not be built into the charger. I havent had any issues to date with the red top Optima. I think I read somewhere it's basically 3 companies in the whole world that make cells for every manufacturer. True or not, I dont know or care to investigate it. Basically use a good brand battery with a good warrenty and charge it accordingly when idle for long periods. It's a battery in a car. It's not a plane. I guess you could go down the rabbit hole and be an expert on batteries if that's your field or expertise but for the regular shmoes that want a battery that works when the key is turned, just about any battery will fill the bill, good brand name, good warrenty. You want ultra lightweight and cranking amps your going to pay through the nose for something. But why?
Something to check though when buying an Optima from a local parts superstore. The date on it. Sometimes these batteries sit for years and the dont get rotated out. I think I had that issue when I bought one of my Optimas. Think when I bought it it had been sitting on the shelve almost 3 years.
What I have been trying to tell you is these batteries are sensitive to a specific type of charger, many older chargers are constant current chargers that can damage these batteries. Do yourself a favor an follow manufacturers recommendations. Unless you were the engineer that designed the product you dont know what you dont know !!!
So the alternator in a car changes the voltage to compensate for installing an AGM in the car? Oh that's great to hear.
Wait, what's that? The alternator doesn't do that? Oh, so it doesn't matter what charger you put on the battery............. like I thought
Yeah, don't need to be an engineer to know common sense stuff. I keep talking specific terms and you keep using general terms. Yes constant current is bad, I never said anything about a constant current charger, I said FLOAT charger. Float is just enough voltage to keep it from discharging. It's like I am talking to the f ing wall sometimes.
So the alternator in a car changes the voltage to compensate for installing an AGM in the car? Oh that's great to hear.
Wait, what's that? The alternator doesn't do that? Oh, so it doesn't matter what charger you put on the battery............. like I thought
Yeah, don't need to be an engineer to know common sense stuff. I keep talking specific terms and you keep using general terms. Yes constant current is bad, I never said anything about a constant current charger, I said FLOAT charger. Float is just enough voltage to keep it from discharging. It's like I am talking to the f ing wall sometimes.
Like I said before.....your the expert !!
I'm done, over and out !!
Ideal charging voltage for AGM battery is different than flooded lead acid battery. But frankly neither battery is getting what it wants with the alternators in our cars anyway. Both types of batteries are being under charged in winter and over charged in summer.
AGM are less tolerant to the summer heat scenario because there's not much fluid in the battery and dries out much quicker when over charged. AGM don't have as good cranking performance as a comparable flooded lead acid battery either. It's not gobs worse, but the good old flooded lead acid battery is really good at the task of starting. At least that is the case with the heavy duty Group 4D batteries I'm familiar with.
Where the AGM battery shines is with discharge cycling. A flooded lead acid starting battery is intended to stay at a high state of charge all the time. Failing to do so sacrifices life. AGM batteries are more tolerant to moderate discharge cycles and will last many times longer than a flooded lead acid battery. So if you're the type that stops and starts a lot, or lets the car sit in the garage for long periods and doesn't give a hoot about maintaining batteries, then the AGM will probably last a lot longer for you.
also has thinner lead plates which equals more surface area, deep cycle, etc....
I think cranking performance and deep cycle capability are at odds with one another. Starting batteries use many thin plates for delivering high current to the starter motor, but the thin plates are susceptible to corrosion when the battery is discharged. Deep cycle batteries use thicker plates that better resist corrosion when discharged, but don't deliver as good starting performance. Corrosion on the plates is not reversible so preventing corrosion is important for a battery that experiences discharge cycles.
The Optima Yellow (deep cycle) did have less cranking amps than the red top (starting)...
But the Odyssey one I just got, since it uses flat plates instead of spiral, has 15% or more surface area vs Optima, is deep cycle and has more cranking amps too, I have a 75/86 with 760 cca, I checked on Rock auto, the "replacement" is 680. Another replacement on Advance auto ws 650 cca.... Optima red of same group 720, yellow 620...
I don't work for any battery company... just love my third gen... and looking for work
I was just reading about AGM batteries and recalled this thread, thought I'd relay this info.
Warning! Do not install the AGM battery in the engine compartment.The AGM battery must not be installed in the engine compartment on account of the high spatial temperature differences, otherwise its service life will be significantly shortened.
reference is at bottom of page https://www.newtis.info/tisv2/a/en/e...ystem/1LiMpr2r
I think the battery manufacture knows that a battery made for a specific group will be used in an engine compartment.
Then again, maybe that's why the Optima batteries don't last for shyte, people are installing them in engine compartments and they don't realize this.
Mine was always mounted in the hatch area. Optima batteries are subpar for other reasons. Alot of people running other brand agm replacing lead acid under the hood no problem. Never heard this before. General Disorder probably has alot more experience in this dept to give an opinion.
Ideal charging voltage for AGM battery is different than flooded lead acid battery. But frankly neither battery is getting what it wants with the alternators in our cars anyway. Both types of batteries are being under charged in winter and over charged in summer.
AGM are less tolerant to the summer heat scenario because there's not much fluid in the battery and dries out much quicker when over charged.
Batteries must have proper charging voltage to deliver long service life. AGM batteries are ALWAYS.... let me repeat, ALWAYS overcharged in our cars during the heat of summer. Service life will be much shorter than flooded lead acid batteries if you drive a lot in summer.
I havent heard of problems of Agms in the engine bay. Please read before you go after my statements.I've had problems with one agm brand, Optima, and its always been in the hatch. So no I kinda havent.
Sometimes in my job I have to talk to real battery experts. This website helped me with some of the basics so I could have a somewhat coherent conversation with them.
By the way, it's not as though the AGM battery can't be underhood, it just needs proper charging voltage regulation to be happy underhood. Max ambient temp rating for the battery is probably around 50°C. Problem is our alternators are overcharging the battery pretty much all summer.
But high ambient temps will reduce battery life even if voltage regulation is correct. The battery is happiest at room temp (about 70°F). Rule of thumb for every 10°F above 70°F, the battery life is reduced about 20% (if I remember right.... maybe don't remember right). So you can expect shorter battery life underhood even if everything was designed right.
By the way, it's not as though the AGM battery can't be underhood, it just needs proper charging voltage regulation to be happy underhood. Max ambient temp rating for the battery is probably around 50°C. Problem is our alternators are overcharging the battery pretty much all summer.
But high ambient temps will reduce battery life even if voltage regulation is correct. The battery is happiest at room temp (about 70°F). Rule of thumb for every 10°F above 70°F, the battery life is reduced about 20% (if I remember right.... maybe don't remember right). So you can expect shorter battery life underhood even if everything was designed right.
Good points, all. I used to swear by optima's red top. I live in Arizona, where the Underhood temp's murder batteries. Lead-acid batteries= 2-year service life. AGM= 3-year service life. When Optima batteries were U.S. built, I could expect 5 to 7 year service life, which made them a bargain at roughly twice the price of a quality lead-acid battery. The pair of Optima's I put in my Chevy Crew cab dually just died after only 3 years. No bargain there. It's a real shame, but I am going back to lead-acid for the dually, at least for now.
DR.K.
04-17-2019, 10:28 AM
So the alternator in a car changes the voltage to compensate for installing an AGM in the car? Oh that's great to hear.
I keep talking specific terms and you keep using general terms. Yes constant current is bad, I never said anything about a constant current charger, I said FLOAT charger. Float is just enough voltage to keep it from discharging. It's like I am talking to the f ing wall sometimes. 
