I've been posting on why I don't think the BadDog batteries are worth the money (and maybe pissing folks off as well). I thought I'd give some links to some stuff on the technology of AGM batteries in general.

Here's a marine installers perspective on them, and some surprising things about them -- like, better have a good alternator, lol! Also, if you kill them (excessive discharge) they might not come back without "help".

http://www.bitwrangler.com/wt/lv-ab-agm.html

Here's a GREAT primer on battery technology in general. Pay particular attention to "types of batteries" if you're flirting with deep-cycle batteries and so on.

http://www.windsun.com/Batteries/Battery_FAQ.htm

A Wiki on AGM's:

http://en.wikipedia.org/wiki/Absorbed_Glass_Mat

Yet more AGM description:

http://www.reactual.com/metaefficien...ies/index.html

One theme that keeps recurring here: AGM's don't really have any more power than conventional batteries -- just low resistance allowing high peak discharge (and charge, lol) currents. This means that a SMALLER battery will have much less power available IN TOTAL.

Watch out for this as people try to sell you TINY batteries based ONLY only size and the fact that they can deliver peak amps.

The main advantages of AGM's are that they are not sensitive to mounting position, are inherently "safer" than standard batteries, have a lower "self discharge rate", and high peak currents.

They do appear to be easier to damage with bad charging and certain discharge conditions, however, so be aware of that.

There's a lot more out there on these -- but PLEASE be wary of marketing claims and instead pay attention to the FACTS about the technology!

 

Another good one comparing capacity, cost, and weight (marine batteries, but scale it down to our type...)

http://www.vonwentzel.net/Battery/01.Type/

Looks like generally speaking, you get about 10% more power per weight on AGM's. So an "equivalent" battery would be about 10% lighter than a conventional battery, in general. Actually, other savings on the casing may allow a bit more.

Popular Mechanics article:

http://www.popularmechanics.com/auto...y/1266741.html

And how could I have left out Optima's tech FAQ:

http://www.optimabatteries.com/publi...ology/faq.html

 

I want an Optima Battery! I know alot of people who have them and love them.

 

They're FANTASTIC, and actually worth the price they cost. However, they do require attention to detail, lol. They can be killed also.

Also, for some reason or other, AGM batteries have a higher failure rate than conventional ones, or so it seems. I know of several people who's Optima's died within a year. Not knocking Optima, per se. It just seems like it's possible to get a bad one like anything else -- just a little more likely.

 

I personally run Optimas in all of my stuff.

Those articles fail to mention Optimas. In a marine environment (I'm not talking about sailing), Nothing I have seen so far has held up like an optima. Everything else I have tried works 2-3 years.

Roach-they are great batteries.

N3els, on the optima failures, was there a small draw on the battery for a while? By a while I mean long enough for it to go dead. That will hurt every other battery I have seen. The optimas when below 7volts wont charge back up with a standard 10amp craftsman/garage charger. You have to ***** slap them with 50-60 amps for 45min or so, on the High maintence free setting.

 

I'm not sure. Real data is hard to come by on these things (since no one is usually paying attention) so I don't know.

That "reformation" charge is exactly what they need. But higher voltage automotive chargers will KILL them dead if they are used on them often, except for that purpose (bringing back a deep discharge battery).

An Optima, or a pair of them, may eventually be in my truck for winching purposes. I've been watching and it SEEMS like the reliability may be improving? Don't know.

MANY of those links were from people who either make a competing battery, or don't sell Optima's, lol. So it's no surprise they weren't mentioned.

I didn't mean to leave them out since they and the Exide are probably the best known AGM batteries to the general public. I just had a problem getting to their site this morning for reasons unknown and had to post the link later.

 

I have only had one single problem with an optima. Have sold/installed around 20 of them. I have one in my ranger, and 2 in my boat. The single problem was with one fully discharging (some putz turned the navigation lights on) for the trip to Marathon FL, and it wouldnt recharge on the small charger. Back at the shop, on the big charger, worked fine since. This is a marine cranking battery that has been in the boat since 01. It has held up through a lot.

A company made a G-Shock recorder. I was told than 1 G of shock was equal to a 3' free fall. The gauge would show 10G's of shock. It broke half way through the first lap. Next race, new gauge, same thing. Worked fine on a smoother lake.

This was in a 29' offshore race boat.

 

for what its worth john, i have/had a total of 5 optima red tops in vehicles, the oldest of which, that is still in use, is about 4 years. the first 2 years it spent in the torino, for one year it was used in my infamous bronco, where it was attacked by a blazing inferno of a battery cable (internal resistance of the cable) the battery case was a little melted, but now its found its way back into the torino, where it sits, connected, and the car is started about once or twice a month. always starts just fine. i have had similar luck with my other optimas, but while at autozone i did have one optima come back to me, bad in about a year, but that was about 4 years ago, im sure their quality has since improved

 

And I'm wondering now, as I see more on the AGM's in general, if some of those weren't victims of discharge abuse. Maybe that's been the problem all along and then people can't get them back online and return them because they don't know the "trick".

Interesting stuff. Thanks for all the info and experience, guys!

 

I was wondering how I could ever recharge my Optima red top, and the high output alt. myth has been answered for me.

I always thought AGM batteries were packing more output, but not thanks to you I know thats B.S.

I am now an educated man.

Thanks John.

 

Well, they can make more peak current, but they may not have more total CAPACITY. They still have many advantages, provided you can use them properly, IMO.

 

yeah you have have the strongest battery in the world, but what it worth if it doesn't last as long as a regular battery. Anyway, Otima will be the only thing I ever use, they are your audio systems best friend too.