AGM Batteries

[ksurfer2]

In an effort to take some weight out of my car, I am considering switching to AGM batteries. I currently have 2 batteries wired in parallel and mounted in the trunk. Can the AGM batteries be wired in the same fashion? I think switching out the two batteries for 2 agm's may save quite a bit of weight. Also, since this is pretty much a race only car, when parked, I keep it on a battery maintainer. Can the battery maintainer (Battery Tender brand) I am currently using be used with AGM batteries, or are there specific maintainers for AGM batteries?

Are there any downsides to AGM batteries? From what I have read so far, I haven't found any.

 

[Darter6]

I just bought a deep cycle AGM type 24 and it's about the same weight as what I was replacing.
Your best bet is research amp hours, cold cranking, and your intended use meaning a race car.Some are race light weight but have a limited reserve. Not to worry if you charge between rounds. Are you running a alternator ?
I have seen some battery chargers that say "Not for AGM use" but I believe those are cheap knock off's of good battery maintainers. I have Battery Tender brand chargers and they work fine with AGM. I still would double check with your manufacturer's serial number from Battery Tender to make sure.

 

[Aron Gleason]

The battery tender I have, says right on it AGM. And I leave the tender hooked up all the time.

 

[RemCharger]

I agree, haven't noticed much weight difference.
And a good Ole tenderizer isn't going to help much going rounds.

 

[YY1]

I have an AGM scooter/ lawn mower batter.

It weighs about 1/2 of what the lead acid battery weighed.

Cost is really the only down side.

The lead acid battery was $25.

The AGM was $70.

 

[dadsbee]

Sounds like people are mixing up AGM's with Lithiums. AGM's weigh damn near identical to lead acid batteries.

AGM's, there is zero reason to leave a tender on one! I park my airplane in late September and fire it back up in May and never even put a charger on it. Battery is now 11 years old. Cars I charge them each once about mid Winter. They generally start charging showing 90% and take about 5 minutes to click off FULL.

Lithiums... not a chance in my vehicles.

 

[Darter6]

The AGM was $70.

Put one in my Suzuki scooter. 'bout choked at the price.It is the size of a pack of cigarettes.
I do think they are superior. It may be me, but they last longer.

 

[dvw]

I swapped out two 12 volt for one 16 volt. Best move I ever made. The bad is you need a 16 volt alternator and charger.
Doug

 

[biomedtechguy]

I have been using AGM and Lithium batteries in vehicles that used plate lead acid batteries, boat, classic cars, and motorcycles, so I have a range of experience.
AGM are basically the same weight as "regular" lead plate acid batteries. What I like about AGM is they seem to last longer and are more durable, less prone to failure, nearly impossible to leak.
They SHOULD have an adjustable mode selectable charger or one made for AGM.
Lithium batteries are featherweight compared to the others, ABSOLUTELY require a dedicated Lithium battery charger, and they don't do well if there's any draw on them at all when the vehicle isn't used daily, so I recommend a mechanical disconnect. If they weren't so perfect for the high position on the 2 V-Rods I have, I would switch to AGM.
I have had several Shorai Lithium motorcycle batteries fail, along with at least one dedicated Shorai charger, all expensive and seemingly well made.

 

[R413]

I bought a group 24 AGM. Heavier than a lead acid. Works great! Lots of amperage. And takes a long time of sitting before it needs a charge. Had it 10 years now. Worth it so far.

 

[Darter6]

Had it 10 years now.

That's good life.Only 1 Optima did I have last past 10 years. The next 4 didn't make it past 4 years.

 

[moparedtn]

At least in my '04 Ram, going with the upgraded AGM battery some years ago netted nothing, other
than the pricier tag, of course. The AGM battery did not last any longer than the lead acid one it replaced.
When it needed replaced again last year, I went with a Wally World jobber (Everlast?).
If it lasts even half as long as the AGM, I'm money ahead.
Oh - the only lithium batteries up here on the ridge are for my collection of power tools - and they make
me nervous enough that I don't like to leave them on the chargers.

 

[33 IMP]

I'm with Dadsbee, and moparedtn.
The agm optima reds I've had weigh at least what a lead acid battery does, and in my case in my diesel pickup, didn't last any longer.
I compared warrantee of Sam's agm (die hard?) to their lead acid, and the warrantee and power were the same. Would have been over $500 for two optimas, got two lead acid for less than $250. If they last more than half as long as the agm's, I'm ahead.
On the other hand.... my Opel has ABYSMAL battery access, and currently a optima red doing fine. When the time comes, it will get another.

 

[Aron Gleason]

I have 2 AGM batteries that failed after only 3 years in My Diesel Ram.

 

[Darter6]

They don't make 'um like they used to !!

 

[Photon440]

The agm optima reds I've had weigh at least what a lead acid battery does

Most likely because AGM batteries are lead acid.

 

[33 IMP]

What I heard is that a lot of agm's are getting thrown away, because they got discharged, and won't recharge, even with an agm charger.
The secret is to parallel a good battery with the dead agm, so the charger starts. Supposedly lots of "dead" agm's in battery technicians cars......

 

[Photon440]

What I heard is that a lot of agm's are getting thrown away, because they got discharged, and won't recharge, even with an agm charger.
The secret is to parallel a good battery with the dead agm, so the charger starts. Supposedly lots of "dead" agm's in battery technicians cars......

I've had some 'dead' ni-cads that I successfully recharged that way too. Battery charger has spaces for two, so pop in a good one and when the charging light goes on, insert the stubborn one and it'll charge up.

 

[biomedtechguy]

AGM batteries are lead acid.

I was going to add that to one of my posts, but I specified "lead plate acid" for "regular" batteries.
AGM benefits from the design, IMO, especially if leaks on your classic car would be something you want to avoid.

The secret is to parallel a good battery with the dead agm, so the charger starts

THIS! and use a charger w/AGM selectability or dedicated use.

 

[Bird 426]

I had an Odyssey in my airplane, saved 10 lbs. They usually have an average life of 8 years. They are fussy about being charged correctly, can be life limiter if you are not in the window, 13.9-14.2. Yes, a dead battery can be recharged.