unless access is an issue i like flooded + in hotter dry climates they my last longer if kept topped up by charging + distilled water. sealed batteries can dry out + no way to add fluid it dies. aunts 99 jeep cherokee went 7 years on a flooded auto zone battery. be aware higher cost AGM's are pushed so you may need to know the physical size-group as well as terminal location.
AGM vs. Flooded
- Thread starter garageman402
- Start date
Is there a downside to using AGM if your vehicle calls for a lead acid battery? What about the charging system? Can it distinguish the difference?
Can a charging system designed around a lead acid battery be damaged over time by a AGM battery?
From what I've read, lead acid / AGM respond differently to charge / discharge rates. What is the biggest advantage of switching from lead acid to AGM.... Or is there one?
I know the newer electronic battery chargers have a different charge setting for AGM over lead acid. Your vehicles charging system is not similar. It's not going to know the difference. Hence it could be damaged.
Can a charging system designed around a lead acid battery be damaged over time by a AGM battery?
From what I've read, lead acid / AGM respond differently to charge / discharge rates. What is the biggest advantage of switching from lead acid to AGM.... Or is there one?
I know the newer electronic battery chargers have a different charge setting for AGM over lead acid. Your vehicles charging system is not similar. It's not going to know the difference. Hence it could be damaged.
Downside is more cost and possibly no more benefit.
The cars systems will undercharge an AGM not severely though.
AGMS have two main advantages - self discharge rate is lower so things that sit a lot can benefit. (this can be offset with a maintainer)
They have less internal resistance and can be charged quicker - this is a big deal say on the water where you have limited run to to charge a battery. park the boat on a sand bar switch to one - run it dead on the stereo, switch back to 2 fire up and its going to take everything your alternator can throw at it.
Lead acids "like" no more than 20% of their face value AH in incoming charge rate - and less is better.
An AGM can often take 100% or more of its face value in charge rate.
minor benny - There is no water to boil out in high temps.
Do any of them have the battery in the trunk or under passenger seat? That's typically where you have a vent tube.
I will rely on what a johnson controls rep told me. Absorbed Glass Matt AGM has a problem with charging. he told me that the matt is about as thick as toilet tissue and it's easy to 'blow a hole through the matt' I post this because he NEVER told me anything that didn't prove to be true. I spoke to a friend at NAPA just the other day that runs 12 delivery trucks and he said that visits from factory reps have pretty much ended for ANY product. I agree with UNCLEdave if the charging system is designed for flooded AGM may be a problem.
Man. AGMs have been around a long time, that’s the first I’ve heard of blowing a hole through the mat. Only someone who takes them apart would be able to determine that. They Do suffer by drying the mat, permanently, if overcharged. The mat is typically similar to fiberglass - sturdy, so I’m not really sure the rep is correct here.
yes-and they charge up quicker, resist overcharge, and self discharge slower
True story. Tonight.
my buddy just bought a classic corvette and we went over there to get it. We needed a 12V inflator to pump up the tires, and I pulled the agm starter battery out of my larger generator to run it. It’s a power sports AGM from Walmart. The generator was last run in the fall, when I drained and fogged it. The battery saw a short maintainer charge probably in December. I yanked the battery and threw it in the truck with a charger running from the inverter, expecting to pull a few amps. It immediately went to full charge and stopped, and I thought, it’s done… not accepting a charge.
we got to the sellers house, and oh my. The little battery absolutely delivered, inflated all the tires, and ran the pump with authority. It pulled a full 10amps from the charger on the drive home.
and we got the car… with a lot of work.
the low self discharge with the agm’s is real. I’m quite impressed with this one, a Jci powersports unit from Walmart.
my buddy just bought a classic corvette and we went over there to get it. We needed a 12V inflator to pump up the tires, and I pulled the agm starter battery out of my larger generator to run it. It’s a power sports AGM from Walmart. The generator was last run in the fall, when I drained and fogged it. The battery saw a short maintainer charge probably in December. I yanked the battery and threw it in the truck with a charger running from the inverter, expecting to pull a few amps. It immediately went to full charge and stopped, and I thought, it’s done… not accepting a charge.
we got to the sellers house, and oh my. The little battery absolutely delivered, inflated all the tires, and ran the pump with authority. It pulled a full 10amps from the charger on the drive home.
and we got the car… with a lot of work.
the low self discharge with the agm’s is real. I’m quite impressed with this one, a Jci powersports unit from Walmart.
I think the plain AGM batteries are a reasonable option to consider. I bought two at Walmart for my pickup.
Not so sure about the fancy & expensive AGM like Northstar, spiral wound.
Not so sure about the fancy & expensive AGM like Northstar, spiral wound.
garageman402
$100 Site Donor 2024
Was cleaning up old (!) email when I stumbled across your post. I had an AC Delco Professional 42 month group 48 flooded battery in my Buick that I installed 12/2018 with a date code of 029 (02/2019). The battery in my van was a 30 month battery that died in month 31 (around 02/2022), so now I'm suspect of the 38 month old battery in the Buick. Replaced it, & gave the old one to my son in law because he could use it in his shop & it was still "good". Well, he stacked it up with his other junk batteries where it sat for better than 1 year. Earlier this year he acquired a 72 Duster which we needed to drive to my house & store it, with a dead battery. I said hey what about that one I gave you? We pulled it out, it tested 12.8 volts, put it in the Duster, she cranked & fired! Unbelievable!!
While parked in my shop, I had a battery maintainer on it, & 3 months later it was dead. This from a flooded battery.
Similar threads
