Are AGM Batteries an improvement over typical lead acid battery?

[SGKent]

Saw a post in an Acura forum on AGM batteries in Acuras and Honda's and some general warnings. Thought I would post a link here since it probably applies to all AGM batteries. I found the comment on Honda adding a fan to cool them as well as flooded cell batteries interesting. https://www.mdxers.org/attachments/b15050c-pdf.76210/
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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[Little Steve]

When I was doing yacht repair work we had a few customers that liked to install new batteries every couple years need 'em or not. Thus I got a two year old West Marine (Made by East Penn) AGM Group 24 free. Probably three years old at the time, so it's now five years old plus however long it sat in warehouse and store. Works great, no leaky leaky. Works good in cold or hot weather. This was a great investment. We put West Marine AGM batteries in a lot of boats. The only problem I ever remember was when we used a different brand someone wanted to use. As far as the one I put in the bus, I mentioned it being sealed, and I don't get the massive terminal corrosion I always got with the flooded one I had before that (and the one before that etc...), nor do I have to check the wet cell levels. Pretty much maintenance free in that respect.
I don't drive it much anymore, but like to start it and warm it up occasionally and or make a store (beer) run to keep things moving around.
If I were to winter store it I would probably get a decent maintenance float charger.
One boat I worked on had a house battery bank of three D4 AGM batteries (Big boat with a big inverter). A couple years ago the battery charger died and the hot house electronics discharged the batteries (similar to modern autos). I was able to get some charge back into them but they were never the same, wouldn't take a full charge, and using the inverter was iffy. Needless to say, Those were $700 each. AGM's do not like to be fully discharged, especially if they sit drained.
Before I retired we had installed Lithium Ion batteries in a big racing sailboat. Wow those are light weight. Pricey. The Engine Start battery was much smaller than a Group 24 and it cranked over a 75 hp Yanmar diesel no problem. I was impressed. I was around for another year and never had any problems even though the owners left stuff on without the charger plugged in and drained them a few times. Hum? I could see taking a bunch of weight out of the rear end.

[Abscate]

Battery performance is like oil changes, wide variations In Experience based on operating habits.

For daily drivers, the cost of AGM does not justify the benefits

Boat people with very different criteria than VW people and also,have deep pockets
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.ssS!

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[Little Steve]

[quote="Abscate"]Battery performance is like oil changes, wide variations In Experience based on operating habits.


So true! However I do try and change the battery oil regularly regardless of what my friends say.

[Abscate]

[quote="Little Steve"]

[jlrftype7]

I'll add my two cents since all I see and work with for the most part are AGM batteries on current Jaguar and Land Rover models. JLR switched over to them like other manufs, in a big way. Expensive compared to conventional batteries, and they DO like to be charged with Chargers that have an AGM setting on them versus any old charger you have lying around that has worked for your vehicles for years....
I have seen them bounce back from vehicles that drained them flat out, but they aren't particularly good at that either as noted by other posters.
They really do seem to hold a charge better for stored vehicles, so for all those new or used cars sitting on our lots, you don't run into low or dead batteries at any rate like we did in the past where it was mandatory to run vehicles or charge them up weekly to keep the battery up.

Years ago, I didn't have much luck with Optima Red Top batteries lasting as long as a regular battery, but the interstate AGMs we get as replacements for the European/Stock AGM batteries, which could be made anywhere in the world as we know.... , hold up pretty well in terms of service life.
The single most common fault I run into is a lost cell internally, so you end up with an intermittent no-start as that cell goes in and out of connection, dropping the available voltage down.

So, they're here to stay at the moment until something else takes their place on the High End vehicles.
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'68 Westy- my first VW and vehicle/Bus- long gone.- sold it to a traveling Swiss couple....
'67 Type 3 Fastback, my 2nd car- gone
'69 Semi-Auto Stick Shift Beetle-gone
2017 MINI Coopers, our current DDs
‘84 Tin Top - Hilga....Auto

[Abscate]

My favourite on boating Fora are the guys who want AGM because they don't want batteries that can spill of they capsize.

These are from guys whose boats never leave the dock, let alone get into waters where they can capsize a 30,000 pound boat.

And, Im on that list, I am way too old to go out in weather which is beyond my capabiities.
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.ssS!

[Clatter]

I'll say it again, cause I'm like that..


Used to be that the old Optima, and also copies of them, were the best thing since sliced bread.
I LOVED my old red top!
The car would sit all winter while I built another motor,
Left the thing on the wet concrete outside in the rain,
Pop it back in, and cranks right over.
The things were like magic; lasted over ten years of outright abuse.

What with spill-proof, and no acid fumes boiling out inside the cabin.
(In a beetle this can be important, especially if you end up on your roof)

Oh, they would get abused in a no-start cranking session,
or jumping the toads around where I lived that always had a dead bat.

I had a yellow top in my bus that would charge our phones and such for days in a row without being started.

Life with those expensive AGM Optimas was good.


After years of abuse, it was a no-briner to replace despite the cost.
But,
Alas,
Things had changed..

Sure,
They said 'optima' on the side and cost $200+,
But something had changed...

The one that sits kept going flat.
Same car as ever - recent alt and new harness; no stereo.
I use a special 'smart' charger with an AGM setting on the low 2A..

Same with the yellow-top in my bus.
Expensive piece of absolute shit.
Lasted just two years - just enough for the warranty to run out.

Replaced with the cheapest lead-acid type they had, and problem solved.
It wasn't because of my car or it's cables/wiring/ etc.

So maybe I got a bad run of them,
But the people in the field who I talk to had the same story.
AGM manufacture went overseas,
And the quality went with it.

So,
Go ahead and quote some article on the Internet,
or cut/paste some sales literature.
Maybe even talk about how well your old AGM works to this day..

But I'll tell you first hand.
The last couple I got were total shit.
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Bus Motor Build

What’s That Noise?!?

[jlrftype7]

The one I had was back in the early 2000s. I think I got 2 years out of it.

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'68 Westy- my first VW and vehicle/Bus- long gone.- sold it to a traveling Swiss couple....
'67 Type 3 Fastback, my 2nd car- gone
'69 Semi-Auto Stick Shift Beetle-gone
2017 MINI Coopers, our current DDs
‘84 Tin Top - Hilga....Auto

[SGKent]

[quote="Abscate"]

[mikedjames]

I used to use AGM on my boat, with a modified alternator regulator set to AGM because I could get them cheap and the engine is a 330cc Yanmar 7HP diesel with a tiny starter, so even computer UPS batteries would work (the cheap ones..).

But leave the marine VHF on for a week and that would kill the battery forever.

I now use the cheapest wet cell batteries. They effectively last as long.

I also treat them regularly with double virgin battery oil. No need to worry about terminal corrosion, or quantum defects.
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Ancient vehicles and vessels

1974 VW T2 : Devon Eurovette camper with 1641 DP T1 engine, Progressive carb, full flow oil cooler, EDIS crank timed ignition.
Engine 1: 40k miles (rocker shaft clip fell off), Engine 2: 30k miles (rebuild, dropped valve). Engine 3: a JK Preservation Parts "new" engine, aluminium case: 26k miles: new top end.
Gearbox rebuild 2021 by Bears.

1979 Westerly GK24 24 foot racer/cruiser yacht Forethought of Gosport.
1973 wooden Pacer sailing dinghy

[Abscate]