Yeah, I think you could be right (based on other posts). I was just referring to him not necessarily having to buy another battery; he'll have to see how it holds a charge.

All is well. Sorry for the panic attack. I ended up buying a new battery and it's fine now (so far). I didn't think it was the battery although about a month and a half ago I picked it up from the shop and it was dead, I figured they left something on. Got it charged up then jumped and it was fine. No problems since then.

When I was vacuuming I had literally started it up and drove it into the garage, turned it off, vacuumed for 3-5 min then it was completely dead which is why I wrote off the battery. Doesn't make sense it was running fine 5 min ago and now nothing. I appreciate all you guys help. I'll keep an eye on it and update if anything changes. I did notice that when I got into it yesterday the clock wasn't set and I could swear I set it when I put the new battery in but it was the first time I had driven it since then so we'll see.

did you figure out how to code it too or just plunked the new battery in?

Good to hear. You may consider having the battery 'registered' if you can find someone to do it for a reasonable 15-30 minute charge. By the time it gives you any 'problems' it will be a few years down the road and the symptoms will be a worn out battery, with reduced life as compared to having it registered when new.

No I just hooked it up and fired it up. I had some error messages regarding AWD and DSC but they went away before I got out of the neighborhood. No error messages of any kind and everything is running fine. I thought I had read somewhere that the battery wasn't coded in this years model. The car feels like it still drives the same. How would I know if it needed coding or not?

Registering and Coding a new battery

Make sure you understand the difference between “registering” and “coding”.

Registering: doing this tells your ECU that you are replacing your OE battery with an equivalent. An equivalent is defined as same battery type (wet cell vs AGM type) and same Amp Hour rating.

The only two AGM batteries I have found to be form-fit-and-function compatible with the OE BMW battery for the ’08-’10 e70 is the Duralast H8-AGM and the Deka 9AGM49 (as a matter of fact, the Duralast is made by Deka for Autozone).

Register the new battery with the ECU requires that you know the Amps/Hours (AH) rating of your new battery. If you don't know the AH rating, you can calculate it based off of the Reserve Capacity rating, which is generally easier to come by (should be stamped on top of the battery).

Calculating AH rating based off of the Reserve Capacity rating:
Amp/Hours = (Reserve Capacity / 2) plus 16 (i.e. If your battery had a Reserve Capacity of 100, you would get 66 AH rating)

To register the battery you need to have a K+DCAN USB interface, INPA compatible cable and software.

Software for registering a new battery is available as a free download at Bimmersoftware.com. This software does not allow you to do any coding!

Coding: in the event that you get a battery with a different Ah rating, you will have to re-code the Amp Hour setting/rating in the ECU.

To do this, you need appropriate software to access the settings in your ECU. Unfortunately I do not know how to do this because I have not yet found the appropriate (and easy to use) free software. Dealers charge anywhere from $400 to $600 for this job, including a new battery.

If anyone knows where to get/download the coding software, please share!

Once you have the software, choose the AH ratings option closest to your battery. The available setting are outlined below. The first six are Wet Cell standard style of batteries and the others are the newer AGM style of battery.

KLASSE_BATTERIE:
46ah
55ah
70ah
80ah
90ah
110ah
40ah_agm
60ah_agm
70ah_agm
80ah_agm
90ah_agm

This will re-set the alternator to the correct Amp output for your new battery. If you do not do this, you will run the risk of either under-charging or over-charging your (new) battery. Either is undesirable and will lead to odd electrical behavior.

WWONG and TerminatorX5,

That didn't work for my X5 three nights ago. I had left the glove compartment open overnight. The light in it was still on in the morning. The X5 would not start; the battery was (almost) completely dead. I had to re-charge it.

I tested my battery and it's border-line. I'm going to get it replaced.

basora,

The battery classes that you listed are not correct for our 2008 X5 4.8i models. Not sure what battery I'm getting yet but may need to set that value.