Automotive

Done with AGM batteries!

  • Last Updated:
  • Mar 5th, 2021 9:38 pm
Tags:
[OP]
Deal Expert
Mar 23, 2004
28798 posts
9280 upvotes

Done with AGM batteries!

Thread title says it all. In somewhat ironic fashion I commented on another thread recently that I haven't been all that impressed by AGM batteries over the years. The tech is good the science seems like it should be solid, but the reality is quite different. This is a long post so if you want the full story and experience, pls read. For the TLDR:
1. Optima YellowTop--5-6 yrs.
2. Optima RedTop--15+ years!
3. Exide Edge--5 yrs.
4. Deka Intimidator--3yrs!
Conclusion? AGMs not worth it.

Full story (but for those who want my detailed experiences before they believe me that they're not worht it):
For the people that believe the marketing and all the technicalities of why they should be better? I'm just going to say, "don't be me." I was one of those people for going on like two decades now, and yes they should be better, but really they have not been any better in the real world.

Let's do full rundown of the four AGM batteries I've purchased over the years.

1. First was an Optima YellowTop 34/78 this was probably in 2002 or so I'd say. Bought on intarwebs from an Interstate dealer way back in the day where Interstate was the main distributor for the little-known Optima Battery company (before they were bought out by JC) . Bought it due to it being touted for car audio applications and back then I was a big "car audio guy" I guess you could say so when the battery in my car failed some 5-6 years into the car's life, this is what I bought. Long story short the YT battery lasted...about 5-6 years. Not really any longer than the OE flooded battery that it replaced. I chalked it up to being a not-so-great individual example and/or that it wasn't as good as the Red Top for a regular car application. The shorter warranty of the YT even suggested this. I don't remember what it cost me but it was somewhere around $100 USD which seems like a great deal but at that time that was about $160 CAD and then whatever that ends up being when you account for inflation--probably $200 or so.

2. Anyway, while I had the YT, I actually bought a RedTop 35/75 at Walmart in Canada in 2004 for the low price (relative to what they cost these days) of $130. Walmart Canada has an exclusive warranty for RTs at the time which was 3yr replacement and 10yr total warranty--10yrs being virtually unheard of at the time. I had bought the battery for a "project car" that never ended up panning out and the car was sold as-is, so the battery I'd used a little bit in that car, I kept. It sat for a couple years and then when I got a new car and because I'd put an audio system in that car right away I took out the factory battery and used the RT. In late 2012 the car was written off so I took the battery out and put the stock one in, at the body shop. 8yrs later that battery was still going strong.

3. Sometime, in the middle of all this I bought another AGM, a CT AGM battery that was really a rebadged Exide Edge. This went in the car I purchased in 2012 to replace above mentioned vehicle (note I bought the battery a year or two before this though). This one had a 5yr replacement warranty with no pro-rated portion. About 3-4yrs in I felt like it was getting weak but I was in denial because again I'd drank the kool aid I guess and thought AGM should last like 8-10 years on the long run. But my suspicions grew stronger as it seemed quite weak after leaving it parked daily for 8-10hrs in the winter at work everyday. I even swapped out the "old" RT and low and behold that battery was like 5yrs older than this one and was cranking stronger!

So, I borrowed a carbon-pile load tester (I have my own electronic one now but then I didn't have any load tester). Sure enough it was quite weak. The much older, lower-specced (it was smaller) RT was actually testing better than this battery. I scrambled to find my original receipt which I eventually did and got a replacement...on the very last day of the warranty. Now there used to be a "trick" that if the person at CT didn't know what they were doing you could get a full warranty on the replacement battery, but I didn't luck out as a manager that knew what they were doing did my transaction so the new battery had no warranty. But hey I was getting a new battery. That Edge must have been a dud, right? Exide Edge--lasted about 5yrs.

4. As a replacement, I got another CT AGM but they had switched OEMs by now so the replacement was a rebranded Deka (East Penn) Intimidator. Well yeah that Exide must have been a dud...right? Well I now had a brand new modern AGM to once and for all prove to myself this would last for years and years. Only FFW to last year when I finally got an electronic load tester (an Anel BA201), and it was showing the battery at like 40% and should be replaced, while only like 3ish years into this battery's life! Well no warranty so load tester must be wrong I'll just keep on trucking since it cranks pretty well. Well FFW to this winter. On the -10C and below days, I can tell it's cranking slowly, can tell it's weak :| Still don't want to believe it but I know it'll be time for a replacement within another year or so.

On to a week ago now and by accident I left my keys in the ignition since I had to wind down a window for something. I turned the lights off when I did this to avoid battery drain but somehow I totally forgot to turn the ignition off and then went inside my house (car in garage). Wake up next day and realise for the very first time in my life I did something to accidentally drain a car battery! :eek: Note that it was not below freezing in my garage that morning, plus being AGM it should be "freeze resistant" anyway due to no free-liquid electrolyte. Anyway I boost it with the trusty Gooloo I got (worked great mind you), and off to work I went. Work is only a 10 min drive so I left the car idling for about an hour so as not to leave it flat in the cold. Luckily it was getting to +1C as it has been the past week so wasn't super cold. Car started up fine that day and actually battery seemed fine for a few days after. On the weekend I put it on my desulfator (a battery minder, so not any high-voltage desulfation). It was there for maybe 8hrs or so and then I went to start the car again. Completely, completely struggled to start, even with full charge. Test it with the electronic tester and now it's showing 200-something CCA. It's done (the Deka Intimidator rebrand)! Three yrs! Done!

Keep in mind when I saw this battery starting to get weak as indicated by the Ancel, I started putting it on a charger/maintainer on weekends whenever I wasn't going anywhere, just to try to make sure I was taking the best care of it. My trips to work are very short and yes that's going to be hard on a battery but 2yrs for a $200ish battery? Also for this reason I never blast the blower motor, almost never use the seat heaters, etc. on trips to/from work--try to keep the loading as low as possible.

Oh and what about that RedTop you ask? Well, it finally gave up the ghost. That one was, TBH, a real champion. I will say that much. This battery outlasted not only its 10yr pro-rated warranty, it outlasted every other lead acid car battery I can remember. The thing is it wasn't constantly in use in any one vehicle, but it was in use for years at a time when it was used. It was actually used in some form or fashion in four different vehicles over the years. However last year when using it to start/move my old car (which has sat in the garage for 10yrs now), it was not up to the task. Keep in mind when the RT was not in use it was on the BatteryMinder, so it was fresh off that but failed to start the car without using a booster pack. So it has finally met its end :( That guy was great though, I'll definitely give him that much. I actually think it's more the internal contacts at the top of the battery that join the cells and terminals, that have eventually corroded and become no good, more than the cells. There's a YT video of someone cutting open a BlueTop showing this occurring. RIP RedTop, 2004-2020. 16 years!. They don't make you like they used to either though, and you cost over double what you once did!

Anyway in conclusion, what I did now with no warranty on the CT AGM/Intimdator... I was going to buy yet another $220+ "mighty AGM" battery but by now the Kool Aid has worn off, plus they aren't even on shelves at Costblos anymore--have to be ordered. With experience in four different vehicles, four different AGMs, and a lot of money spent on them? Nah not again friends. One out of four...is bad, and certainly not consistent with the "AGM is bestest evar and lasts longer" kool aid they sell you. I bought a Kirkland (JC) flooded battery with 4yr warranty or whatever it is, for $135 instead. This vehicle it's not a trunk-mounted battery so I'm fine with "downgrading" to a flooded battery in this car (you can even use flooded batteries in trunks too but they're not recommended anymore). As a side note the flooded battery is also appreciably lighter than the AGM. So many years of struggling with cumbersome 50lb+ AGMs, a flooded lead acid of the same size seems darn right light in comparison--and who would ever describe lead-acid as lightweight?! :lol:

My advice on AGMs now has changed after years with using them and seeing only one last any longer than a traditional battery. During this period the premium over flooded batteries has also skyrocketed for unknown reasons. Economies of scale and widespread-adoption has definitely not kicked in here. Back in the 00s when I bought my YT and RT, they were expensive but they really weren't that much more expensive than "premium" flooded lead acid. Today, good flooded lead acid batts are still typically in the $100-150 range; AGMs OTOH are typically $200+--double the price. And Optimas? LOL Optimas are like $300 now! For 100yr old heavy lead acid stuff. Sure it's the latest tech in lead acid, but even AGM itself is like 30 years old by now, And that expensive tech? Doesn't really buy you any more life or performance TBH. Just a waste of money. I encourage people to not buy AGMs unless they are interior/trunk batteries. There are a lot more of those these days, but if you don't got one there, don't buy AGM.
56 replies
Deal Addict
Oct 1, 2015
1286 posts
1544 upvotes
Barrie, ON
Optima really dropped the ball on their batteries. They used to be worth the price premium, now they're garbage. I've had AGMs in my vehicles for years, really haven't noticed much of a difference between them an lead acid to be honest. I am on year 3 of 3 group 31 AGMs in my boat which get heavy use and usually drained down to nothing and charged back up overnight. We'll see how long those last for. The lead acids they replaced lasted me 6 years before giving up the ghost.
Member
Apr 18, 2011
333 posts
105 upvotes
Toronto
I have always used Costco Kirkland car batteries and I have only good experiences to share.
[OP]
Deal Expert
Mar 23, 2004
28798 posts
9280 upvotes
mxthor3 wrote: Optima really dropped the ball on their batteries. They used to be worth the price premium, now they're garbage.
Yeah once they were sold to JC battery (which in turn is now "Clarios") they went downhill I think. Not in the early stages but once JC started cutting costs, etc. on them (and increasing consumer prices mind you) they've become some kind of insanity. Now made in Mexico or whatever and with all sorts of cost-cutting put in place--ugh. The other problem is at a $300 CAD price point, who the heck is buying these now? Next to no one. So guess what else that means--good luck getting a "fresh" one off a shelf--they've probably been sitting a year plus when anyone does buy one at the insane price!
mxthor3 wrote: I've had AGMs in my vehicles for years, really haven't noticed much of a difference between them an lead acid to be honest.
Yeah it seems the pain erm I mean main difference is on your wallet/account. One is like $120 and the AGM equivalent is like $240, or approx. double the price. It'd be one thing if you consistently got better performance and way more life but in practice it seems that's not the case. Reading reviews on AGMs also reveals the same. The people that say they're great basically got a working battery and are satisfied as, well it's a new battery. The long-term reviews are fewer but the common theme among them is that they didn't last any longer than a battery that cost half as much. There are other benefits, sure, but most of them...are they really worth paying 2x the price? The low ESR and everything, oh yeah that sounds great and all but what's the benefit for the average person? None. About that much :lol: The non-spillable and low-gassing nature is of benefit in certain applications but for most people? Just save your money--I think it's the better way to go.
mxthor3 wrote: I am on year 3 of 3 group 31 AGMs in my boat which get heavy use and usually drained down to nothing and charged back up overnight. We'll see how long those last for. The lead acids they replaced lasted me 6 years before giving up the ghost.
For sure would be interested in seeing some review or follow up a couple years from now to see how they're holding up. Based on my experience I doubt they will do any better but wouldn't mind hearing about it later--cross your fingers! When you talk about three batteries, you're also talking about $300-400 premium over the flooded batts, too I'd imagine? :eek:

Would also be interested in hearing from others here who've had AGMs last them like 8-10 years without issue, if any such stories exist!
Banned
Apr 5, 2013
5810 posts
2959 upvotes
keenland
ES_Revenge wrote: Yeah once they were sold to JC battery (which in turn is now "Clarios") they went downhill I think. Not in the early stages but once JC started cutting costs, etc. on them (and increasing consumer prices mind you) they've become some kind of insanity. Now made in Mexico or whatever and with all sorts of cost-cutting put in place--ugh. The other problem is at a $300 CAD price point, who the heck is buying these now? Next to no one. So guess what else that means--good luck getting a "fresh" one off a shelf--they've probably been sitting a year plus when anyone does buy one at the insane price!


Yeah it seems the pain erm I mean main difference is on your wallet/account. One is like $120 and the AGM equivalent is like $240, or approx. double the price. It'd be one thing if you consistently got better performance and way more life but in practice it seems that's not the case. Reading reviews on AGMs also reveals the same. The people that say they're great basically got a working battery and are satisfied as, well it's a new battery. The long-term reviews are fewer but the common theme among them is that they didn't last any longer than a battery that cost half as much. There are other benefits, sure, but most of them...are they really worth paying 2x the price? The low ESR and everything, oh yeah that sounds great and all but what's the benefit for the average person? None. About that much :lol: The non-spillable and low-gassing nature is of benefit in certain applications but for most people? Just save your money--I think it's the better way to go.


For sure would be interested in seeing some review or follow up a couple years from now to see how they're holding up. Based on my experience I doubt they will do any better but wouldn't mind hearing about it later--cross your fingers! When you talk about three batteries, you're also talking about $300-400 premium over the flooded batts, too I'd imagine? :eek:

Would also be interested in hearing from others here who've had AGMs last them like 8-10 years without issue, if any such stories exist!
just curious...when changing agm on a car that calls for agm...did you "marry" or "pair" the battery to the electrical system?..it my understanding that for AGM to work the way its advertised, this is a must.

..as for using agm in non agm type car...i dont think there is a huge benefit
Deal Addict
Oct 1, 2015
1286 posts
1544 upvotes
Barrie, ON
ES_Revenge wrote:
For sure would be interested in seeing some review or follow up a couple years from now to see how they're holding up. Based on my experience I doubt they will do any better but wouldn't mind hearing about it later--cross your fingers! When you talk about three batteries, you're also talking about $300-400 premium over the flooded batts, too I'd imagine? :eek:
There's definitely a premium you're paying for AGM over lead acid. I can't remember what I paid for those batteries but they weren't cheap :)
[OP]
Deal Expert
Mar 23, 2004
28798 posts
9280 upvotes
cardguy wrote: just curious...when changing agm on a car that calls for agm...did you "marry" or "pair" the battery to the electrical system?..it my understanding that for AGM to work the way its advertised, this is a must.
Ha that's just nonsense talk probably so they can have some excuse for why they don't actually fare any better in the long term. Car came with a flooded battery but some versions/trims in ROW do come with an AGM, even when not trunk-installed (which is also an optional setup depending on the engine/trim). There is no such coding option for different batteries, however.

AGM batteries don't have Bluetooth lol, they don't need to be paired. I have the spec sheets and the charge voltage lists (e.g. including temp v. voltage) for both the Edge and the Intimidator. They are the same charge voltages as standard lead acid batteries. In fact these spec sheets caution against over-voltage and the reason is simple--if you gas a sealed battery, there's no way to replace the electrolyte. This is why I've never been a fan of high-voltage desulfation or high-voltage "recovery" of batteries--it's simply a stupid idea on AGMs, which is all I've ever bought in the aftermarket really, but now that has changed of course.
cardguy wrote: ..as for using agm in non agm type car...i dont think there is a huge benefit
So what is the huge benefit (besides low gassing and being non-spillable) in a car that came with an AGM from the factory? Are you saying that in a car that came with one from the factory, then, and only then, is it going to last any longer? "Trunk batteries" BTW already last longer than "engine-bay batteries" because they are not subject to nearly the heat that many engine-bay batts are. Heat is #1 killer of batteries, and they avoid this by simply not being near any big sources of heat...like an engine. The fact that most of such batteries are AGM now for safety reasons, isn't really what's making them last longer.
Sr. Member
May 6, 2010
648 posts
97 upvotes
Richmond Hill
Volvo's OEM lead-acid battery -11 years. (German nade)
Banned
Apr 5, 2013
5810 posts
2959 upvotes
keenland
ES_Revenge wrote: Ha that's just nonsense talk probably so they can have some excuse for why they don't actually fare any better in the long term. Car came with a flooded battery but some versions/trims in ROW do come with an AGM, even when not trunk-installed (which is also an optional setup depending on the engine/trim). There is no such coding option for different batteries, however.

AGM batteries don't have Bluetooth lol, they don't need to be paired. I have the spec sheets and the charge voltage lists (e.g. including temp v. voltage) for both the Edge and the Intimidator. They are the same charge voltages as standard lead acid batteries. In fact these spec sheets caution against over-voltage and the reason is simple--if you gas a sealed battery, there's no way to replace the electrolyte. This is why I've never been a fan of high-voltage desulfation or high-voltage "recovery" of batteries--it's simply a stupid idea on AGMs, which is all I've ever bought in the aftermarket really, but now that has changed of course.


So what is the huge benefit (besides low gassing and being non-spillable) in a car that came with an AGM from the factory? Are you saying that in a car that came with one from the factory, then, and only then, is it going to last any longer? "Trunk batteries" BTW already last longer than "engine-bay batteries" because they are not subject to nearly the heat that many engine-bay batts are. Heat is #1 killer of batteries, and they avoid this by simply not being near any big sources of heat...like an engine. The fact that most of such batteries are AGM now for safety reasons, isn't really what's making them last longer.
I dont know 100%

but...

I did take an industry sponsored course on batteries a few years ago, both agm and regular , and a lot of what you say is contradictory to what they taught...specifically the "marrying" of the battery (only agm) .

what they taught was MB and BMW (at that time) required the programming or marrying to the system otherwise most of the problems you describe would happen.

true? not true? why would they teach this?..what they said makes sense and what they described is what happened to you

i was also told on German vehicles that the ecm actually picks up on a battery identifier?
[OP]
Deal Expert
Mar 23, 2004
28798 posts
9280 upvotes
cardguy wrote: I did take an industry sponsored course on batteries a few years ago, both agm and regular , and a lot of what you say is contradictory to what they taught...specifically the "marrying" of the battery (only agm) .
So what we need a minister now to perform this holy sacrament between the car and the battery? :lol: Oh c'mon, an AGM battery is still a lead acid battery at the end of the day. All that happened was they figured out how to absorb the electrolyte into a glass-based mat (as the name implies)...and with Optima roll it into a cylinder... It still has the same operating voltages, the same voltage per cell, the same low energy density (i.e. why they are so heavy), the same general characteristics as a flooded battery, only better. I'm well aware of the science behind how an AGM is made, and how it works. There's no electronics within an AGM battery or any kind of BMS or something like you'd find in an LiFePO4 battery. At it's heart it's still 250yr old technology, only made a little better.

I am not arguing whatsoever that there is no difference here and that these changes and using absorbed electrolyte don't give quite real and measurable improvements over a flooded lead-acid battery. Those things are all there. Not only was I a strong supporter of AGMs earlier, I actually did learn all about how they work, how they're made, and what the on-paper benefits are. They are certainly more rugged and vibration resistant, they certainly have lower ESR and can deliver current better, they should be more temperature resistant...but in the end how much does this actually benefit the consumer in the real world? Are flooded lead acid batteries actually subject to so much vibration in a typical car environment that their lifespan is significantly impacted? Well, apparently not when you compare to a battery that is, by design, much more vibration resistant. So in this regard vibration isn't a problem for regular car batteries even though they are certainly susceptible to long-term problems from physical vibration.

Do people really need better current delivery to start their vehicles on a day-in/day-out basis? Not really because it's not like people using flooded lead acid batteries (which is still the majority of cars out there I would say), ever thought to themselves--hmm I really need more power to start this car! Nah, they just turn the key and it starts and they go about their business. About 5 years later when it don't start so well they get a new battery and...move on with life.
cardguy wrote: what they taught was MB and BMW (at that time) required the programming or marrying to the system otherwise most of the problems you describe would happen.

true? not true? why would they teach this?..what they said makes sense and what they described is what happened to you
What's the science behind what you are saying? There's no electronics in the battery to "pair or match" to anything. There are no hail marys to be said, religious or cult rituals to perform, so the stars line up "just so" for a damn lead acid battery to work in a car properly, lol. What you're saying might make sense if you're talking about replacing battery packs in a BEV or something where battery performance is so crucial to actually running a vehicle. A battery in a regular fossil-fuel-engined car just serves to start it. Sure it's also a buffer and reserve and all that but really it's not that complicated. Even if you were talking about replacing a lead-acid battery with LiFePO4 then yeah sure those batteries need a BMS to, you know, not catch fire and explode and all that. But what does a lead acid battery, AGM or otherwise need that's so sensitive that if you don't shake salt over your shoulder, hold a seance, have an exorcism done, etc, in order to ensure your precious car battery actually works?

On top of all this point out one battery manufacturer or brand that says any of this or has any sort of disclaimer on AGM batteries, their consumer data in terms of marketing materials, labels, pamphlets that mentions this? Not only that they don't even mention any sort of thing in their more technical documents either (I can give links to some if you want). If it were the case that you had to have programming tools (which I do have incidentally but the majority of the public does NOT), and all kind of rituals, etc. to get one of these uber pricey batteries just to work right then...who would want to buy one? Read any of the FAQs, etc. provided by any of these companies and see where any of them say NO you cannot use these batteries anywhere else except where designed originally and cannot use them without special coding performed. The reality is they say the exact opposite--that anyone can use them and they can replace any regular car battery with no ill effects.

That all said it is true that some cars (many of them now actually) have battery management systems that are coded both for different battery types and for when a new battery is installed. But they don't have to be and the changes the systems make are very minor; furthermore the systems themselves can already detect when a new battery has been installed or when one exists with lower ESR, etc. So the coding simply isn't 100% necessary.
cardguy wrote: i was also told on German vehicles that the ecm actually picks up on a battery identifier?
Oh c'mon man, how would it do that if there's no electronics in the battery? You can code the battery/energy management module for the matching part# on the battery and can specify a new battery is installed but it's not 100% necessary either. Not only that most cars these days German and otherwise do have some sort of energy monitoring/management even if they don't have such very-specific coding options. Some of the cars mentioned here have exactly that--the car's system knows when to inhibit things like seat heating, and other accessories when the energy needs to be used to recover a battery in low SOC for example. BMW used to refer to this as part of their "Efficient Dynamics" thing but many other modern cars have this working behind the scenes without some kind of tradename having to be mentioned.

Anyway as mentioned I'm not trying to argue there are not any technical or scientific differences and actual improvements in AGM batteries over flooded ones. There certainly are. My point is just that, in my experience these benefits have not meant anything meaningful in my real-world use. Only one of four batteries has done anything impressive and these are all ~$200+ batteries if you account for inflation. AGMs have not gotten any cheaper over time, as I mentioned and IMO they certainly should have. But adoption has been slow and costs have remained stagnant at best and it's probably not surprising given the real world benefits just aren't there for the consumer.

I'm only bothering to post this because I see a lot of people posting the same thing I myself have posted in the past. That AGM is better and bestest evar, and what people should be buying if they can afford it, and it's so worth buying and all that crap. And that's what it is, my own previous advice included--crap. I'm simply posting this to tell people that's really not true and they aren't worth it. Sure they are "better" but not really in the way that's meaningful to the end consumer. Most importantly they're not, IMO, worth double the money. If they were like $30-40 more than a regular battery, I'd still be buying another one now. But at 2x the cost? After how much money I've already put into these so-called "ultimate" batteries? Uh no thanks. Even if they were commonly lasting 7-8 years that would be something but it doesn't seem like they can even go that long--longevity certainly isn't a big thing here and the fact that none of them has a truly long warranty any longer, is just more proof of that.

Just putting this out there as actual experience so people can make their own decisions. My recommendation is just for people to save their money here and buy a flooded battery for any engine-bay-battery application. That's what RFD is all about anyway--saving people money, right? I never recommend buying "cheap crap" because it's cheap as it's not going to be good; but at the same time I'm not going to recommend spending twice the money on something I cannot, in good conscience, say is any better than the thing that costs half the money.
Deal Addict
Nov 10, 2018
3986 posts
4169 upvotes
Carmakers are just stupid. Many Audi models have an AGM battery (12v) as standard but the battery belongs where it SHOULD be, which is in the trunk.

Whoever thought it was a good idea to put any battery in the engine bay of a car should be shot.
For legal topics and discussions, the opinion, guidance, and thoughts provided are my own and are not considered to be legal advice, in any manner.
Banned
Apr 5, 2013
5810 posts
2959 upvotes
keenland
ES_Revenge wrote: So what we need a minister now to perform this holy sacrament between the car and the battery? :lol: Oh c'mon, an AGM battery is still a lead acid battery at the end of the day. All that happened was they figured out how to absorb the electrolyte into a glass-based mat (as the name implies)...and with Optima roll it into a cylinder... It still has the same operating voltages, the same voltage per cell, the same low energy density (i.e. why they are so heavy), the same general characteristics as a flooded battery, only better. I'm well aware of the science behind how an AGM is made, and how it works. There's no electronics within an AGM battery or any kind of BMS or something like you'd find in an LiFePO4 battery. At it's heart it's still 250yr old technology, only made a little better.

I am not arguing whatsoever that there is no difference here and that these changes and using absorbed electrolyte don't give quite real and measurable improvements over a flooded lead-acid battery. Those things are all there. Not only was I a strong supporter of AGMs earlier, I actually did learn all about how they work, how they're made, and what the on-paper benefits are. They are certainly more rugged and vibration resistant, they certainly have lower ESR and can deliver current better, they should be more temperature resistant...but in the end how much does this actually benefit the consumer in the real world? Are flooded lead acid batteries actually subject to so much vibration in a typical car environment that their lifespan is significantly impacted? Well, apparently not when you compare to a battery that is, by design, much more vibration resistant. So in this regard vibration isn't a problem for regular car batteries even though they are certainly susceptible to long-term problems from physical vibration.

Do people really need better current delivery to start their vehicles on a day-in/day-out basis? Not really because it's not like people using flooded lead acid batteries (which is still the majority of cars out there I would say), ever thought to themselves--hmm I really need more power to start this car! Nah, they just turn the key and it starts and they go about their business. About 5 years later when it don't start so well they get a new battery and...move on with life.


What's the science behind what you are saying? There's no electronics in the battery to "pair or match" to anything. There are no hail marys to be said, religious or cult rituals to perform, so the stars line up "just so" for a damn lead acid battery to work in a car properly, lol. What you're saying might make sense if you're talking about replacing battery packs in a BEV or something where battery performance is so crucial to actually running a vehicle. A battery in a regular fossil-fuel-engined car just serves to start it. Sure it's also a buffer and reserve and all that but really it's not that complicated. Even if you were talking about replacing a lead-acid battery with LiFePO4 then yeah sure those batteries need a BMS to, you know, not catch fire and explode and all that. But what does a lead acid battery, AGM or otherwise need that's so sensitive that if you don't shake salt over your shoulder, hold a seance, have an exorcism done, etc, in order to ensure your precious car battery actually works?

On top of all this point out one battery manufacturer or brand that says any of this or has any sort of disclaimer on AGM batteries, their consumer data in terms of marketing materials, labels, pamphlets that mentions this? Not only that they don't even mention any sort of thing in their more technical documents either (I can give links to some if you want). If it were the case that you had to have programming tools (which I do have incidentally but the majority of the public does NOT), and all kind of rituals, etc. to get one of these uber pricey batteries just to work right then...who would want to buy one? Read any of the FAQs, etc. provided by any of these companies and see where any of them say NO you cannot use these batteries anywhere else except where designed originally and cannot use them without special coding performed. The reality is they say the exact opposite--that anyone can use them and they can replace any regular car battery with no ill effects.

That all said it is true that some cars (many of them now actually) have battery management systems that are coded both for different battery types and for when a new battery is installed. But they don't have to be and the changes the systems make are very minor; furthermore the systems themselves can already detect when a new battery has been installed or when one exists with lower ESR, etc. So the coding simply isn't 100% necessary.


Oh c'mon man, how would it do that if there's no electronics in the battery? You can code the battery/energy management module for the matching part# on the battery and can specify a new battery is installed but it's not 100% necessary either. Not only that most cars these days German and otherwise do have some sort of energy monitoring/management even if they don't have such very-specific coding options. Some of the cars mentioned here have exactly that--the car's system knows when to inhibit things like seat heating, and other accessories when the energy needs to be used to recover a battery in low SOC for example. BMW used to refer to this as part of their "Efficient Dynamics" thing but many other modern cars have this working behind the scenes without some kind of tradename having to be mentioned.

Anyway as mentioned I'm not trying to argue there are not any technical or scientific differences and actual improvements in AGM batteries over flooded ones. There certainly are. My point is just that, in my experience these benefits have not meant anything meaningful in my real-world use. Only one of four batteries has done anything impressive and these are all ~$200+ batteries if you account for inflation. AGMs have not gotten any cheaper over time, as I mentioned and IMO they certainly should have. But adoption has been slow and costs have remained stagnant at best and it's probably not surprising given the real world benefits just aren't there for the consumer.

I'm only bothering to post this because I see a lot of people posting the same thing I myself have posted in the past. That AGM is better and bestest evar, and what people should be buying if they can afford it, and it's so worth buying and all that crap. And that's what it is, my own previous advice included--crap. I'm simply posting this to tell people that's really not true and they aren't worth it. Sure they are "better" but not really in the way that's meaningful to the end consumer. Most importantly they're not, IMO, worth double the money. If they were like $30-40 more than a regular battery, I'd still be buying another one now. But at 2x the cost? After how much money I've already put into these so-called "ultimate" batteries? Uh no thanks. Even if they were commonly lasting 7-8 years that would be something but it doesn't seem like they can even go that long--longevity certainly isn't a big thing here and the fact that none of them has a truly long warranty any longer, is just more proof of that.

Just putting this out there as actual experience so people can make their own decisions. My recommendation is just for people to save their money here and buy a flooded battery for any engine-bay-battery application. That's what RFD is all about anyway--saving people money, right? I never recommend buying "cheap crap" because it's cheap as it's not going to be good; but at the same time I'm not going to recommend spending twice the money on something I cannot, in good conscience, say is any better than the thing that costs half the money.
not disagreeing with anything you said. Especially the value part of it.

I was only questioning why a professional from East Penn would train and speak about the differences and contradictory statements that you made...i dont really care either way, but..they are the manufacturers and are you saying they are wrong or BS'ing?
Deal Fanatic
Oct 26, 2008
6380 posts
2024 upvotes
BC
angryaudifanatic wrote: ............
Whoever thought it was a good idea to put any battery in the engine bay of a car should be shot.
There are some downsides to having it in the trunk.
Such as much longer cable length and associated loss.
And if a car owner disconnects the battery to perform some task on the battery or the car and absentmindedly closes the trunk, that can be a bit of a problem.

But overall, yes, trunk location is better.
Sr. Member
Aug 21, 2010
893 posts
344 upvotes
toronto
i presently own 6 vehicles right now and out of all vehicles, my volvo battery as well has lasted the longest
Possum77 wrote: Volvo's OEM lead-acid battery -11 years. (German nade)
Deal Fanatic
Sep 1, 2004
6363 posts
4983 upvotes
cardguy wrote: I was only questioning why a professional from East Penn would train and speak about the differences and contradictory statements that you made...i dont really care either way, but..they are the manufacturers and are you saying they are wrong or BS'ing?
I don't know how smart the ECU is but my old 2017 Mercedes had battery not doing well in the final year (3) I had it. No warning. I just bitch about start-stop not working to dealer and I got a new battery out of it. Doing standard battery tests, I never find anything wrong can car always starts.

I think it will only going to get worse as we have more and more always on electronics in the car.

Now the other theory about AGM in German cars is that most put battery in the trunk which is within a passenger cabin. They are apparently safer in terms of leaks/fumes. I don't have 1st hand knowledge on this other than reading about it in forums.
Deal Addict
Apr 22, 2013
2632 posts
1879 upvotes
Markham
angryaudifanatic wrote: Carmakers are just stupid. Many Audi models have an AGM battery (12v) as standard but the battery belongs where it SHOULD be, which is in the trunk.

Whoever thought it was a good idea to put any battery in the engine bay of a car should be shot.
Best one is putting the battery underneath a rear powered seat. Such a good idea...to put a battery under a item that in order to move to access the dead battery...needs battery power.
Deal Fanatic
Feb 4, 2015
6574 posts
2948 upvotes
Canada, Eh!!
Have used CT, Kirkland, Everstart from WMT, AC Delco [garage bought from who knows where], etc. batteries.

Never used AGM batteries but all the above lasted at least 5-6 years [many in areas where -25C and below norm for winter]... no real reason to pay premium.

Plus never did any mtce on above batteries other then cleaning terminals maybe year 3 or 4.

Even in cold temps... always started [did have block heater on -30 C nights] AND never idled vehicle longer then 30 seconds to warm up... most of time just started vehicle, put on belt, started driving moderately.
.......
July 13, 2017 to October 25, 2018: BOC raised rates 5 times and MCAP raised its prime rate next day each time.

2020: BOC dropped rates 3 times and MCAP waited and waited to drop its prime rate to include all 3 drops.
Deal Expert
User avatar
May 10, 2005
36156 posts
10274 upvotes
Ottawa
I bought a 2004 SLK 320 for my Wife 5 years ago and it had an AGM battery in it. It is still in it and it is doing very well. I store the car for 6 months over the Winter and do not disconnect the battery or have any minder on it. Don't have to boost it when taking it out of storage.
Lucky I guess.

Edit: Don't know the brand and can't check as it is in an indoor storage facility.
The Government cannot give to anybody anything that the Government does not first take from somebody else.
Deal Guru
Jun 11, 2005
13134 posts
1969 upvotes
Toronto
Varta AGM battery in my Mercedes lasted 5 years. I replaced it with a Motomaster AGM. I always thought that certain cars require AGM. Lifespan seems to be similar to lead acid. I’m quite certain that my dashcam played a role in killing the battery sooner.
Deal Addict
User avatar
Sep 9, 2012
4301 posts
3573 upvotes
Oakville, ON
cardguy wrote: I dont know 100%

but...

I did take an industry sponsored course on batteries a few years ago, both agm and regular , and a lot of what you say is contradictory to what they taught...specifically the "marrying" of the battery (only agm) .

what they taught was MB and BMW (at that time) required the programming or marrying to the system otherwise most of the problems you describe would happen.

true? not true? why would they teach this?..what they said makes sense and what they described is what happened to you

i was also told on German vehicles that the ecm actually picks up on a battery identifier?
As I understand it, you need to tell the ECM that a new battery has been installed because the ECM changes the battery charging strategy over time as a battery ages. Apparently the system will charge an older battery more aggressively than a newer one ad/or it chooses different points for when a better needs to be charged.

That said, there’s conflicting anecdotes in enthusiast forums. Some say they didn’t register their new battery install and were fine for many yrs/kms while there are other stories of not registering and then batteries dying very prematurely. But there are so many variables at play that I’m not really sure that conclusions can be drawn.

In the end, the Germans all have models that support coding to update that a new AGM battery has been installed. While they’re famous for over-engineering simple things, I have to believe that they wouldn’t install a battery replacement coding feature to the ECM if it had zero benefit/value. And given the requirements for increased fuel efficiency and reduced emissions, it makes sense that having a variable battery charging strategy could be used to optimize when engage charging and when to reduce or disengage charging.

Top