AGM versus lead-acid battery?
 

Beside being slightly more expensive, is there any downside(s) to using an AGM over a regular lead-acid battery on our E53? Would our alternator be able to properly charge an AGM? Thanks.

I have had an AGM batt in my '01, since ~'07, when I replaced the 6+ yr old oe...
Yes, It is due for me to change it out. :D

I see no downside: AGM is a variation of lead acid.
Great tutorial on batts, see #3 and then the AGM description.

Other than slightly more cost, it has no negs that I can determine.
GL, mD

Battery Basics: A Layman's Guide to Batte | BatteryStuff Articles

Agm is better

MD, thanks for the battery link. Since some AGM requires different charge rate, I wasn't sure if it would pose any issues since the E53 wasn't originally designed to use AGM. Good to hear that you have one on your X for more than 7 years without issue. I might pick one up soon.

On a side note, I found it odd that the H8 cost less than the H7. So I may upgrade to the H8 as well since our battery compartment allows for both sizes.

Oh...come to think of it, there's so many wrongs with my title since AGM is also lead-acid and it's also considered a "wet" battery :)

i got an H8 AGM from advanced auto parts - go on line, use their coupon for 15%, pick up the battery from the store, they will email you a coupon for $25 off $50 purchase... I did this and got myself a set of spark plugs - 8 NGKs for $35 take home cost...

Thanks for the lead...but unfortunately, there isn't any advanced auto parts out west :( Best battery for the buck (that I can find) out here in SoCal appeared to be a Duralast Platinum AGM from Autozone...still searching for coupons/promotions ;)

dkl,
Yes, no problem on 'charging' that I am aware of these past several years, with the AGM.
Hellsbells, the X sits all winter in the garage, every other winter season, hooked to a BattTenderPlus run through a mechanical app timer that charges it couple times a week...

Batteries Plus, Autozone, et al, on the Left South Coast.
Fwiw, I put a AZ Duralast in my VetteVert in '11, before our long cross country Road Trip. Still fires up like it's reactor driven...when I get around to replacing the X's batt this summer, I will cop an AZ Duralast for it too, as I have one handy here in Hillbilly Heaven.

Also, you are in the 'Southland' as the local news people like to say, and you are not necessarily fighting Arizona heat or MN cold. That normal Platinum Duralast is a very ood private label batt, imo.

I rec'd you bring your new batt home and slow charge it out of the car for a day/night. Even the most 'careful' parts store, (an oxymoron), will sell you a batt that has been sitting or at best, hot shot charged, imo.

It's a batt; AGM is the way to go. ~$20-$40 diff over a cheapo isn't going to cause anyone to miss lunchola. ;)

GL, mD

I have no issues with Duralast brand from Autozone...but knowing that most batteries brands are by approx 3 major battery manufacturers (Johnson Controls, Exide, & East Penn {DEKA} )...don't limit your search...because you may be able to find a "flooded" lead/acid or "gel" AGM (absorbed glass mat) 49/H8 class size battery from multiple sources that will work for your needs.

Although it looks like you are more inclined for the AGM type of battery...Autozone also sells an H8 DLG "flooded" battery that is a step above their H8 DL battery (and isn't the Platinum H8 AGM battery) that you may want to consider as well if a flooded battery isn't totally off the table. :) See pics below for battery specs/info.

Advanced Auto, Pep Boys, O'Reilly's, Autozone, Sam's Club, Costco, NAPA, Batteries Plus, etc., etc., all sell 49/H8 batteries (again, in both flooded & gel types). You can check their websites, or even call around and get some price quotes...which if you call, you can inquire about any sale pricing or coupons...or even discounts if you work for certain companies. Where I work, we get a discount from Batteries Plus due to a business relationship with them (we buy lots of 1A/2A/3A batteries from them).

And if you are a member of Sam's Club or Costco...you may also find great pricing for a 49/H8 battery:

I know that it's only a battery, and it isn't rocket science. But since the X5 may not get driven daily anymore, I wanted to find something that has the highest possible RC and relatively easy to get my hands on for a reasonable price. May not really care much for the highest CCA or CA as long as it meets OE specs since I may head up the ski resorts in the California winters.

While I understand that there are less than a handful of battery manufacturers, their specs still varies widely among them or even within them. A "flooded" battery isn't totally off the table as my current 5-year old is a "flooded" H7 DLG from Autozone. It's just that for approx. $10 more, I can get an H8 AGM, which somewhat makes it a no-brainer (at least for me) to go with an AGM.

Don't have memberships to Sam's Club or Costco. My local NAPA doesn't have much on their shelves :( Pep Boys and Batteries Plus usually runs $30 or more for an equivalent battery. So it's just a toss between O'Reilly's and Autozone.

My original concern was to see if anyone had ran into any type of issues or see if there were any downsides in using an AGM just in case I decide to head in that direction. But additional research had shown no downside to an AGM (other than being more expensive) and MD is the living prove of that ;), It just made my decision much easier.

In the end, I may just have over-think all of this. Thanks for all the inputs and taking the time to hear my long thought-out processes. This is what 25+ years of engineering will do to you :)

WalMart often has very good pricing on the batteries they sell; used them for my Porsche amd for a standby generator.