Any reason to not switch to AGM?

answer, sure, reason #1 not to switch, marginal cost > marginal benefit

imho batteries are like floor jacks. They're as good as their warranties. Not a whole lot can be substantiated about them, other than that they have the CCAs showing, when brand new. Will they last 1 year? 2? 3? 8? 17? The current battery in one of our cars is 11 right now. I've also had multiple batteries fail in only 1-2 years under warranty. What would AGM do, often time they have the same or lower RC than lead acid. Aren't they good when sitting or mounted upside down etc.?

When all is said and done, aren't there only 2 major battery mfgs in the US, and technically a 3rd smaller one?

Btw I get my batteries from Costco. Price is reasonable and they do honor the warranty.

Somone online stated just get a new battery every 2, and I said wth is that, battery for life club? That person said yep. So I decided to call the bluff and was shot down by Costco, they said it doesn't work like that. If you get a battery replaced under warranty, it carries the original warranty, it doesn't start over. makes sense. But I then said, I heard on the internet I can get a new battery every 2, and the internet is full of truth :ROFLMAO:
 
Nope. Just went through the thread and you don’t mention anything about a stick welder. Your posts are a little hard to understand.
sorry bout that. Am on 2 battery threads right now.
Use the welder, run up 3 cycles of higher charges while connected to the bat. Do so outside as the off gas is poison. top off 1st. each cycle 1/2 hr. Ck level, top off as needed.
"...posts are a little hard to understand...."
C if I can find Scotty, Uncle Tony or Vice Grips explain, will post URL here:
EDIT:
ohtay
 
Lifepo4 batteries (that I know of) aren't designed to be starting batteries. .....
They are available for SLI use in a vehicle, but very expensive.


...Fast-forward a decade, and Antigravity is now one of the leading suppliers of lithium iron phosphate batteries not only for powersports applications, but 12V automotive battery replacements as well. "There were other companies that got started around the same time that we did, but they were unable or unwilling to evolve as new technologies became available," Schafer tells us.

"The real hurdle we needed to overcome was developing an internal management system that makes these batteries safe and durable in these types of applications. We knew the product needed to meet a certain standard, and that's why we developed our battery management system—it protects the lithium from getting into situations where thermal runaway could be an issue due to overcharging or other problems. And the type of lithium chemistry we're using is iron phosphate, or LiFePO4. In general, this is considered to be the safest lithium technology available today."...
 
They are available for SLI use in a vehicle, but very expensive.

Anybody that knows anything about Lifepo4 batteries knows the challenge of charging them with normal automotive alternator and voltage regulator. The author didn't mention that at all. No sir, not me.
Another challenge is they cannot be charged at temps below freezing. Discharging is limited below freezing. Some have builtin heaters.
 
There is no way that your vehicle runs for any period of time at 12.4-12.6VDC. 12.6VDC isn’t full-charge voltage. The only time I see this is when driving after the battery has been on a charger and fully charged. Otherwise, the voltage should be 14+ VDC or at least in the 13s for a proper float voltage.
My truck usually pops up to 15V every morning for 10-15 secs and in the summer with low electrical load/high temps will hover around 12.3-12.8 on the dash display unless the headlamps are on.

Here's some more info about the charging system controlled by the ECM/BCM.
Charging System Operation
The purpose of the charging system is to maintain the battery charge and vehicle loads. There are 6 modes of operation and they include:
• Battery Sulfation Mode
• Charge Mode
• Fuel Economy Mode
• Head lamp Mode
• Start Up Mode
• Voltage Reduction Mode

Normal duty cycle is between 5–95%. 0–5% and 95–100% are for diagnostic purposes, with 0–5% monitoring for an open circuit and 95–100% monitoring for a short to ground at a fixed 13.8 V.
Font Material property Number Parallel





Charging System Modes

Battery Sulfation Mode
The BCM will enter this mode when the interpreted Generator output voltage is less than 13.2 V for 45 minutes. When this condition exists the BCM will enter Charge Mode for 2–3 minutes. The BCM will then determine which mode to enter depending on voltage requirements.

Charge Mode The BCM will enter Charge Mode when ever one of the following conditions are met:
• Windshield wipers are ON for more than 3 s.
• Climate Control Voltage Boost Mode Request is true, as sensed by the HVAC control module via serial data. High speed cooling fan, rear defogger, and HVAC high speed blower operation can cause the BCM to enter the Charge Mode.
• The estimated battery temperature is less than 0° C (32°F).
• Battery State of Charge is less than 80%.
• Vehicle speed is greater than 145 km/h (90 mph)
• A current sensor malfunction exists.
• System voltage is determined to be below 12.56 V

When any one of these conditions is met, the system will set targeted generator output voltage to a charging voltage between 13.9–15.5 V, depending on the battery state of charge and estimated battery temperature.

Fuel Economy Mode The BCM will enter Fuel Economy Mode when the estimated battery temperature is at least 0°C (32°F) but less than or equal to 80°C (176°F), the calculated battery current is less than 15 A and greater than −8 A, and the battery state-of-charge is greater than or equal to 80%. Its targeted generator output voltage is the open circuit voltage of the battery and can be between 12.5–13.1 V. When fuel economy mode is active, the generator is not charging, only maintaining open circuit battery voltage. The BCM will exit this mode and enter Charge Mode when any of the conditions described above are present.

Headlamp Mode The BCM will enter Headlamp Mode when ever the head lamps are ON (high or low beams). Voltage will be regulated between 13.9–14.5 V.

Start Up Mode When the engine is started the BCM sets a targeted generator output voltage of 14.5 V for 30 s.

Tow/Haul Mode (if applicable) Pressing the Tow/Haul Mode button located on the center stack, the vehicle system voltage is raised and the remote (non-vehicle) battery will be charged. Having the headlamps on will raise the system voltage and if the Tow/Haul button is applied it will not serve any purpose. The voltage is regulated between 13.9-14.5 V.
 
  • Like
Reactions: Y_K
The short answer is that if your vehicle's charging system is not optimized for charging AGM batteries, you won't get maximum life out of one.

However, the AGM batteries do tend to have zero issues (IME) with corrosion and crusty terminals, so it depends how much that is worth to you.

At Costco, the AGM batteries are $179 vs. $109 for conventional. Warranty is the same. ROI probably isn't there, truthfully.
 
My agm Optima Redtop lasted 9yrs (2014-2023) in my stock non-optimized 224k mile 2007 Toyota FJ daily driver. Never any leakage or corrosion. Never put a charger on it. I did foolishly leave the key ON, engine off, a time or two over the years and had to jump start it.

It got weak recently, so I replaced it with another Redtop - $260 with discounts from AutoZ

I replaced the original alternator @ 198k miles in Dec of 2019 with a rebuilt Amazon Denso - $66.

The 1st battery (2006-2014) in this vehicle was a Panasonic brand flooded lead acid. It came in the vehicle when new (2006). Never any leakage or corrosion either.

Both great batteries in a great vehicle.
 
  • Like
Reactions: Y_K
So here is how it works in the real world from a tech. Lead batteries can throw a lot of electricity into a starter in a short burst. Absorbed glass mat batteries can handle more load and stay charged a lot longer. They are used due to the demands of loads placed on battery now by assisted driving, Heated and Ventilated seats, Start-stop engines, Remote starting, phone operated starting, Backup cameras, Satellite radio and wireless internet, sound amplifiers all the amenities. An alternator does not put out 14.4 volts constantly. While driving after engine warmed up it might push 13.2 volts and sometimes I’ve seen it as low as 12.8. AGM will be an upgrade for a vehicle that comes with a flooded battery, will get longer life from it and alternator will work less.
 
The short answer is that if your vehicle's charging system is not optimized for charging AGM batteries, you won't get maximum life out of one.

However, the AGM batteries do tend to have zero issues (IME) with corrosion and crusty terminals, so it depends how much that is worth to you.

At Costco, the AGM batteries are $179 vs. $109 for conventional. Warranty is the same. ROI probably isn't there, truthfully.
Optima red tops leak...I've had three in the last three years. I posted about it on a Ferrari forum and a couple Ferrari techs said they had experienced the same, and one posted a similar photo. Here is an example of one of mine: (leaking out the two black vents caps on top)
Never had this issue with Interstate or AC Delco (Varta) AGM batteries.
 
  • Like
Reactions: Y_K
My agm Optima Redtop lasted 9yrs (2014-2023) in my stock non-optimized 224k mile 2007 Toyota FJ daily driver. Never any leakage or corrosion. Never put a charger on it. I did foolishly leave the key ON, engine off, a time or two over the years and had to jump start it.
Any/all AGMs will vent if over charged. They are designed to do that.
 
Just to update: I ended up going with the Honda 51R (# 31500-SR1-100M) battery. It was pretty competitively priced at $135 (excluding core / taxes) with a decent warranty - 3-year full replacement warranty and 100 months "pro-rated." They were diligent about capturing my basic info for the warranty as well.

I had a better look at the old battery and it had no branding on it whatsoever so it was either the most generic battery ever or it was likely the factory battery.

Thanks for the feedback everyone! I'll report back if it doesn't last as long as I had hoped.
 
Any/all AGMs will vent if over charged. They are designed to do that.
I didn't think I owned an AGM battery, until my FiOS UPS started beeping. It has an AGM that I got off of amazon. It's not laying flat on a horizontal surface, which I think is a place where AGM has an advantage to lead acid
 
FiOS ? (expensive FAST cable/modem)?
UPS ? (the delivery boys) ?
AGM - can B mounted any position (mine aint upside down
but on it's sida w/o issues (inc drip or extra gass venting ( smelly farts)
 
If you got 6 years out of that tiny battery consider yourself VERY lucky. Hondas with small batteries are know to fail every 2-3 years almost like clockwork. If you’re not the original owner of the car then I’d suspect it was changed once before.
I had a Canadaian Tire branded battery in for 2005 Civic for 9 years . I am not sure who makes their batteries. It is currently on its third battery just one year ago. Correction, two years ago
 
Last edited:
yeah, I routeenly get 8 yrs or so from my mini battery (24 or #31500 which seems 1/2 size) just like any other car battery. I have a 19 y/o car but asa 'car guy' I keep all systems clean, ship shape'n in order. This helps bat.s last longer (well, everything). In known condition - gotta ol POS like this
they call a battery tester (I call an alternater tester) aahahahaa
that just told me "it's nota cold snap makin it hard to start ur ol junk taday, the altern's goin/gone buddy.")
 
So what about the EFB (Enhanced Flooded Batteries), would that be a reasonable choice to upgrade from a standard battery but not AGM?
I have not seen any information on whether EFB's require a different charging profile than traditional batteries, but if they do not, then it may be a more technically sensible choice than AGM's. However, it seems like you can buy an AGM for less money than most EFB's.

 
I've got a battery that's almost ready to be put out to pasture, so I've been starting to look at candidates.

The application predates the wide adoption of AGMs, so they wouldn't be an optimal choice.

EFBs, provided they have a more flexible charging profile, could be a good alternative, but they cost as much as, if not more than AGMs, and the warranties aren't necessarily any better, just mostly the same. Availability could also be a concern, especially if a warranty repalcement is required. Exide also seems to be the primary supplier, and many have thoughts about their products.

Truth be told, I'm finding it hard not to just drop by Costco and pick up another battery to replace the previous Costco that's been in place for ~7 years, and a good $50 or greater less costly than getting one elsewhere with a different label. Or, opting to pay +$60 for the AGM version that might be chronically undercharged in that particular application.

Tried and true will likely win out.
 
So what about the EFB (Enhanced Flooded Batteries), would that be a reasonable choice to upgrade from a standard battery but not AGM?
It makes sense if you are a short-tripper, or your vehicle is not driven most days of the week, or if your vehicle has the start-stop feature and came from the factory with an EFB battery. The carbon based additive in many EFB battery brands increases the rate of charge acceptance, and increases the cycle life under partial-state-of-charge operation.

Autozone's Duralast Platinum is available as an AGM or EFB. In a group35 size, the EFB is $10 cheaper than AGM. I am not 100% sure, but the Duralast EFB may be manufactured by Stryten in the USA. Stryten also manufactures the carbon-enhanced Exide Marathon EFB battery

 
Last edited:
I've got a battery that's almost ready to be put out to pasture, so I've been starting to look at candidates.

The application predates the wide adoption of AGMs, so they wouldn't be an optimal choice.

EFBs, provided they have a more flexible charging profile, could be a good alternative, but they cost as much as, if not more than AGMs, and the warranties aren't necessarily any better, just mostly the same. Availability could also be a concern, especially if a warranty repalcement is required. Exide also seems to be the primary supplier, and many have thoughts about their products.

Truth be told, I'm finding it hard not to just drop by Costco and pick up another battery to replace the previous Costco that's been in place for ~7 years, and a good $50 or greater less costly than getting one elsewhere with a different label. Or, opting to pay +$60 for the AGM version that might be chronically undercharged in that particular application.

Tried and true will likely win out.
I think the choice depends on several factors:
1) Do you like a truly "maintenance free" battery that never needs fluid checks?
2) Do you never want to deal with the risk of corroded or crusty terminals?
3) Did the car come with AGM originally, is the charging profile optimized for it?
4) Do you daily drive the car? (that tends to lean toward flooded for a car that came with flooded)
5) If the car is a rarely driven car, then alternator charging profile probably has less impact, since it will be on a battery tender more than being charged by the cars alternator.
6) Budget, is the $50 or $70 going to break the bank?

I'm liking AGMs more and more, after going through a couple flooded East Penn batteries in my old daily driven BMW (2001) in short order. I have a AC Delco "made in germany" AGM now for four years, and still tests great on my load tester, exceeding its rating. I'm not finding the charging issue to be a big deal...I wonder if it really is. I noted that Consumer Reports in their testing, like AGMs and discuss their typical better performance and life. Though there are still some excellent performing flooded batteries, but depends on what size or application. They never mention the potential shorter life of AGM if charging profile is not optimal.
 
Back
Top