AGM BATTERY

Yeah, please define 'compromising performance' and 'long term health' for me. I get 5+ years on AGM. You have been reading entirely too much of the fine print.

 

There's several stages especially when charging. Also, there's bulk and float.

7 stage charging is a very comprehensive and accurate charging process that gives your battery longer life and better performance compared to using traditional chargers, they also help restore drained and sulphated batteries. The 7 stages are: Desulphation; Soft Start; Bulk; Absorption; Test, Battery Recondition and Float.

 

well, ok.

"compromising performance" means that the battery could have worked better, provided more voltage under the same loads, and at lower temps, for longer.

"long term health" means that the battery would last longer and/or perform better over the same amount of time.

These are simple concepts.

I havn't been reading any fine print. I'm just aware of the chemistry differences between the two and how the voltage affects that.

 

So let me see if I have this straight; AGM type batteries are a mass produced battery for mass produced vehicles, that by nature requires special charging parameters that must be systemically adjusted for proper care and feeding of their battery? I could be wrong, but I have never seen anything stated on these AGM batteries that warns / informs the consumer that they must go into the guts of their car's computer to adjust the charging voltage. If these AGM type batteries are that sensitive and different, you would think the battery would come with all sort of warning labels saying that it required changes to the alternator output in order for their warranty to remain intact.

OP; go buy yourself a run of the mill 24F crap lead acid battery at Wal-mart and be happy!

 

Many vehicles come standard with AGM batteries and the charging system is designed and programmed to maintain them from the factory, no messing about required. AGM is not an off the shelf replacement battery for flooded, it just has some advantages over flooded (and some disadvantages) that some find worth the extra cost and modifications. If you look up a replacement battery for your truck, an AGM will not be something recommended. Kind of like putting LED headlight lamps in a halogen housing. They turn on and look bright, but they don't work as well. Just because they fit and function, doesn't mean it's correct. I think most euro vehicles use them pretty much in everything the last several years. I know BMW has been using AGM for over a decade.

 

Doesn't all that just apply to deep cycling?
At what % of discharge does each stage take place?
If you're using it only as a starter battery, the <5% discharge is recharged in which stage; absorption or float?

 

Yeah, but you pretty much are making the case that if you have to fuck with it to make it work right, then it probably does not belong there to begin with.

 

Well sure, to an extent. There is usually a compromise to changing things. If you understand the system and how it works, whether it be the battery/charging system, lighting system, suspension, tires, etc then you can make an informed decision about if the changes you make are worth the tradeoff, cost, etc.

 

I tend to disagree with you a bit here. I don't disagree about the "not really getting full value out of AGM given the cost without mods to charging or hassle of topping off". That's legit. But there are multiple advantages to an AGM battery even on stock charging which may have enough value to offset the cost (they do for me):

1. Better on demand peak current draw for amps, compressors, winches, etc
2. Better recovery from full discharge (light or fridge left on)
3. Better ability to maintain charge over time when not used (I'm driving very little these days and I have 3 vehicles)
4. Less sulfur discharge on fancy battery strap jewelry we didn't need to buy in the first place (I threw this in just for laughs)

Feel free to shoot me down if I'm wrong on any of those 3 but for me it's worth the 3x cost even at stock charging. Particularly with the minivan and a wife and kids, a few extra dollars to provide a small level of insurance against needing a jump at the wrong time is money entirely well spent.

Granted, I do intend to get my arse in gear on charging voltage at some point, that's on my list.

EDIT: Maybe not really disagreeing with you tbh. Just not overly enamored with the analogy of LED bulbs in a halogen housing. I think both types of batteries are entirely OK for use in a Tacoma.

 

That would probably depend on the specific battery used, its capacity, how much it's actually being charged based on driving/use, etc but I could see a large capacity AGM at some percentage of charge less than 100% and still being better able to handle those things that you mentioned compared to the stock flooded or similar battery.

The LED analogy was the only thing I could think of at the moment and it's not very good but the point I was trying to make is still stands in a narrow context.

 

Every time one of these threads pop up, it’s amazing how misled some people are

you can 100% run an agm battery with zero modifications. It’ll be at slightly less than what is 100% but it’s not enough really to even matter. You may get *slightly* less life but it’s not significant. Most of them have a 5 year warranty so who cares? It’ll get replaced if it doesn’t last.

I’ve run them stock, with bumped voltage, with solar panel.. it really depends what you are doing.

people get worked up about the charging voltage, but in the real world it makes almost zero difference. The thing people seem to forget is how long it takes to charge a battery. If you are running for 5 minutes, it’ll make zero difference. If you are running for hours at a time, you’ll see some benefits.

if you have heavy power demands, you should run solar or a second battery with bcdc charge controller.

If you are making zero changes to the vehicle, I’d still go agm unless you can’t afford the battery.. but considering it’ll last longer, it’s really not much more expensive.

 

"If you are making zero changes to the vehicle, I’d still go agm unless you can’t afford the battery.. but considering it’ll last longer, it’s really not much more expensive."

This is true. Diehard AGM Platinum is $30 more than the Diehard Gold 24F.

 

My .02 Cents

All of my off-road vehicles (ATV’s, Dune Buggies, Dual-Sport MC) get AGM batteries since in the past I’ve had issues with traditional ‘wet’ batteries leaking in those vehicles.

My trucks all have ‘wet’ batteries. Yes, they (especially my Taco) go off-road, but not to the extreme that my Dune Buggy does. I typically get about five years out of my batteries. I generally go up a size (or more if I can) on battery size to get more Reserve Capacity. Plus some of my trucks sit for up to a month at a time.

To the OP, I would go with a parts-store ‘wet’ battery. It’ll save you some money and will likely last as long as an AGM would in your application. FWIW I’ve had good luck with Autozone batteries. The OEM batteries on my F-550 lasted about 1.5 years. The Autozone replacements are 3.5 years old and are still working great!

 

My last AGM battery went 9 years in a Camry that obviously wasn't designed around it.
I preemptively replaced the OEM battery in my current Tacoma with and AGM the week I drove it home from the dealer three and a half years ago, and I don't expect it will need replacement for another four or five.

I've been improperly using AGM's, or maybe I should say, running them under less than ideal conditions, in a lot of applications for what must be 25 years now, and it just keep working for me.

None of the inevitable sulfuric acid damage, no hydrogen sulfide corroding everything in the vicinity.

To each their own, but lead acid batteries have been in the rear view mirror for me for a long time.

 

The Platinum Die Hard regular battery has a 4 year free replacement warranty and it's cheaper than the AGM. That's what I put in my truck. I live in AZ where batteries rarely last past 2 years but if you're looking for bang for the buck, that's the way to go. The AGM warranty is 3 years.

 

My last AGM battery went 11 years in a Land cruiser that obviously wasn't designed around it.
I preemptively replaced the OEM battery in my current Tacoma with an AGM the week I drove it home from the dealer two and a half years ago, and I don't expect it will need a replacement for another three.

I've been improperly using AGM's, or maybe I should say, running them under less than ideal conditions, in a lot of applications for what must be 31 years now, and it just keeps working for me.

None of the inevitable sulfuric acid damage, no hydrogen sulfide corroding everything in the vicinity.

To each their own, but lead acid batteries have been in the rear view mirror for me for a long time.

I first started using AGM in 1990 with my 5 year old Toyota 4x4 truck. Same year I started rock crawling, that's when I found that wet cells did not like being on their side.

 

I think what a lot of people are missing in all these conversations is that in most vehicles AGMs work perfectly fine because the alternators usually put out 14.4 volts or so. BUT THE TACOMA SMART ALTERNATOR DOES NOT!!! It only puts out around 13.9 volts, which is fine for charging most standard lead acid batteries to 100% capacity. An AGM requires, as many people above mention, around 14.3-14.7 volts to reach 100% capacity.

So yes, people who have been running AGMs in their vehicles off and on for the last 30 years, yeah, it worked perfectly fine. But you didn't have a Tacoma 30 years ago with an alternator that wasn't properly charging the AGM, lol.

And yes, I do have the Voltage booster in my 2nd gen Tacoma. The purpose of it is to tell the computer of the truck that the alternator is putting out .5 or so volts less than it actually is. And since it's a smart alternator, the computer can tell the alternator to work harder/crank up it's output voltage. Tacoma alternator is putting out ~13.9 volts, but the voltage booster tells the computer it's only 13.4, so the smart alternator starts cranking out 14.4, and now the computer sees 13.9 and is happy.

 

I'll soon be four years in with the 3rd gen & an AGM, when should I expect trouble.

 

You shouldn't. The AGM can handle not being fully charged, but you are just missing out on the full capacity of the battery. As others have stated above, you should still get the other added benefits of an AGM, just not the rated capacity of the battery.

 

Where you been? Anytime there's an AGM thread, this gets brought up; including this one.