AGM vs. SLA Batteries?

[scotts216]

Anyone have any thoughts on the usage and difference between the newer technology AGM (advanced glass mat) batteries and the old standard SLA (sealed lead acid) batteries? Anyone have experience with the AGM's? Performance compared to the SLA's?

The AGM's seem to be suited for formula cars???

Any thoughts appreciated......

[DB4 Tim]

You may have already read this....however

AGM, or Absorbed Glass Mat Batteries

A newer type of sealed battery uses "Absorbed Glass Mats", or AGM between the plates. This is a very fine fiber Boron-Silicate glass mat. These type of batteries have all the advantages of gelled, but can take much more abuse. We sell the Concorde (and Lifeline, made by Concorde) AGM batteries. These are also called "starved electrolyte", as the mat is about 95% saturated rather than fully soaked. That also means that they will not leak acid even if broken.
AGM batteries have several advantages over both gelled and flooded, at about the same cost as gelled:

Since all the electrolyte (acid) is contained in the glass mats, they cannot spill, even if broken. This also means that since they are non-hazardous, the shipping costs are lower. In addition, since there is no liquid to freeze and expand, they are practically immune from freezing damage.
Nearly all AGM batteries are "recombinant" - what that means is that the Oxygen and Hydrogen recombine INSIDE the battery. These use gas phase transfer of oxygen to the negative plates to recombine them back into water while charging and prevent the loss of water through electrolysis. The recombining is typically 99+% efficient, so almost no water is lost.
The charging voltages are the same as for any standard battery - no need for any special adjustments or problems with incompatible chargers or charge controls. And, since the internal resistance is extremely low, there is almost no heating of the battery even under heavy charge and discharge currents. The Concorde (and most AGM) batteries have no charge or discharge current limits.


AGM's have a very low self-discharge - from 1% to 3% per month is usual. This means that they can sit in storage for much longer periods without charging than standard batteries. The Concorde batteries can be almost fully recharged (95% or better) even after 30 days of being totally discharged.


AGM's do not have any liquid to spill, and even under severe overcharge conditions hydrogen emission is far below the 4% max specified for aircraft and enclosed spaces. The plates in AGM's are tightly packed and rigidly mounted, and will withstand shock and vibration better than any standard battery.


Even with all the advantages listed above, there is still a place for the standard flooded deep cycle battery. AGM's will cost 2 to 3 times as much as flooded batteries of the same capacity. In many installations, where the batteries are set in an area where you don't have to worry about fumes or leakage, a standard or industrial deep cycle is a better economic choice.



AGM batteries main advantages are no maintenance, completely sealed against fumes, Hydrogen, or leakage, non-spilling even if they are broken, and can survive most freezes. Not everyone needs these features.

[Pop Chevy]

Let me relate a little story for ya. I used to drag race a Harley. I could get 2 to 3 events out of a SLA batt. The bike shook them apart internally due to the high vibration at high rpm. I lost in the finals in a national event at Englishtown because the batt shorted out AT THE STARTING LINE ! Boy was I pi**ed ! Could have been my first national win. Switched over to a AGM Spirocell batt and could run a full season without failure. Changed it out every season just because ! I will never consider anything else for a racing machine. Think about it.
BTW, I did go on to win a few Nat's.and almost won the championship.

[scotts216]

Thanks for the input. Everytjing I've read makes the AGM's out to be superior to the SLA's. Just looking for some real world experiences to back that up.

[Bill Steele]

I used an AGM battery in my Crossle for 3 seasons. It seemed fine in every respect. No problems.

[Nardi]

Are the AGM batteries lighter than the SLA batteries? If so approx how much?
Thanks

[924RACR]

Am I correct in assuming that the Optima batteries are indeed AGM?

OK, yeah, I see that now on their website (had to look it up!)... spiral-cell AGM.

Perhaps not as fancy as the race-dedicated batteries, but sufficient for my ITB car; I put one in back in 2001 IIRC.

It's still in there, in 2010, and works fantastically well. It not only survives the winter sitting in the car, in the cold MI winters (yes on a kill switch of course), and can crank it up in the spring no problem... it's also survived some pretty heavy, high speed (for an ITB car) hits! The most recent one was getting t-boned by a Volvo, in the driver's side a-pillar right at the battery, sent the car to the frame rack.

Incredibly durable and long-lived. Can recommend them without hesitation.

[kea]

I think that technology was originally from Gates and was called the type BC (beer can). The prototypes of it were built, using a Coors beer can for reference.