Thanks for the update. :thumbup:

I think it was 5 amps draw sitting with the door open and the car off, just the lighting itself has a lot of draw in this X5. I've always been impressed with the X5 for having a battery able to keep up with it's electrical demands.

I just received a Deka 9AGM49 from Remy Battery for my 2004 3.0i. It was just under US$200 shipped. The original equipment battery is 7 years old, so it's definitely due for replacement.

After ordering, I did a little more reading about AGM batteries, and I have to admit I now have reservations about putting one into this car. My concern is that the e53 charging system will charge it too much, or not enough, and then I'll just be replacing the battery again in 2 years. Maybe I shouldn't worry so much. Are any of you folks actually using this battery?

Anyway, I'll report back soon on installation.

AGM batteries charge just like any other battery....what did you read that gave you reservations?

There's this thread: http://www.xoutpost.com/bmw-sav-foru...m-battery.html

One member (pete540) says he's using a BMW AGM battery in his e53 with no problems. That's good.

On the other hand, it seems maybe AGM can be damaged over time by charging voltage/current combinations that wouldn't harm wet cells, so, for example, you can't use any old charger, but need one made for AGM. I couldn't find any definitive statement that the e53 (in USA) charging system has the correct profile for AGM batteries.

Actually, AGMs can use any battery charger...just as any wet cell battery. This is per Braille and Odyssey. Whomever said they couldnt use a normal charger was misinformed. The thread you linked to is full of misinformation. The alternators on new BMWs are even more powerful than the ones on those of yesteryear. They all have voltage regulators, or they'd overcharge ANY battery that they were attached to.

Deep Cycle Battery FAQ, or Absorbed Glass Mat Batteries

I have been running the Braille battery for 8 months now, in both my X and M5 (the M5 has been for 1.5 years, and required foam blocks to keep the battery in place as it is specced for a 95R). I dont have to leave the car not being driven on a tender, as the AGM holds its charge much much much better than a conventional BMW battery.

I would highly recommend the Braille 49 endurance for any BMW.

Thanks for putting my mind at ease, E55AMG2.

I installed the Deka 9AGM49 last night, and it was a perfect fit in the 3.0i. The battery compartment has two threaded holes in the bottom for the hold-down clamp. With the new larger "group 49" battery, I simply used the second hole.

The Deka has a vent hole on each side of the manifold, even though it is supposedly a sealed unit. I attached the vent hose to one hole, and plugged the other one with the plug from the old battery. Start to finish, the job took me 1/2 hour. I attached a bench-top DC power supply to the jump-start terminal under the hood during the swap, so I didn't lose my radio settings.

In regard to your first sentence, keep in mind that while AGM's can use any battery charger, the optimal charging voltage and rate is a bit different, strictly speaking, from wet batteries. Just have a look at the CTEK Chargers for example:

http://www.xoutpost.com/bmw-sav-foru...w-one-fyi.html

The US 3300 model has 3 modes essentially. Per the manual:
1. Mode 14.4 V / 0.8 A - This mode is normally used for batteries < 14 Ah. (depicted by the little motorcycle).
2. Mode 14.4 V / 3.3 A - Normal setting for wet batteries, maintenance free and for most Gel batteries. Some gel batteries prefer a slightly lower voltage. Please consult the battery manufacturer when in doubt. (depicted by the little car)
3. Mode 14.7 V/ 3.3 A - This setting is recommended for a battery at temperatures < 41 degrees F. It is also recommended for many AGM batteries like Optima, Maxxima and Odysses. Consult your battery manufacturer when in doubt. (depicted by the little snowflake and sealed battery logo)

Great tip on the source using Remy Battery since they will ship unlike many other vendors.

I'll invite you along with me to the PRI (performance race industry) show next year. I spoke with the mfgs of all of the above mentioned batteries. Braille, the manufacturer of the battery I linked they told me it's more or less marketing hogwash. All of their batteries (AGM or wet) are designed to be charged anywhere from 12-14.1V (ie the output of an alternator). What's most important is amperage. They told me their car batteries work best when tended at 2A at a minimum of 12V. So long as the charger makes at least 12V and 2A, it wont make one lick of difference. I've owned Optimas and Odysseys as well....all worked perfectly fine with my Die Hard (rebadged schumacher) battery charger at 2A. So unless my charger is magical, Im pretty sure it's just an old wives tale.

The only thing that's voltage critical is when you are trying to code modules or reflash firmware. I'd want a minimum of 12.5V for doing any of that.