E70 Battery Replacement - DIY

[kankou]

Originally Posted by CleanIsFast

Could a low charge battery lead to electrical problems? I currently have no radio, comfort access, bluetooth, PDC after letting the vehicle sit for a week. It's a 2011 and original battery

Certainly can. When the original battery on our 2012 was starting to go out, the Comfort Access was one first functions I noticed to stop working.

[CleanIsFast]

Originally Posted by kankou

Certainly can. When the original battery on our 2012 was starting to go out, the Comfort Access was one first functions I noticed to stop working.

Interesting, I'll have the stealership look into it. It would seem weird to have a faulty amp when they replaced it 1 day before I picked it up. Could very well be the battery is on it's way out. I would assume a new battery through the dealer will be expensive

[kankou]

give them a call for a battery replacement/register quote. my dealer wanted "around $500".

i bought a battery from auto zone for $195, and also bought Carly software and wifi dongle to register it myself. total is less than $500 and I now have a Carly I can use for other purposes

[DWill]

Originally Posted by kankou

give them a call for a battery replacement/register quote. my dealer wanted "around $500".

i bought a battery from auto zone for $195, and also bought Carly software and wifi dongle to register it myself. total is less than $500 and I now have a Carly I can use for other purposes

You used Carly to register/code your new battery ?
I looked into buying Carly, I didn't see battery registration/coding in the list of features. I sent them a email asking if battery registration/coding could be done with Carly and they replied saying it was not supported.

Because of that reply I didn't buy it.

Maybe I got bad information ?

[CleanIsFast]

Guy on here earlier posted it was around $325 or so. $250 for battery and installation/registration

[ard]

If you buy Carly, they will extort another 9.95 for the battery coding, as I recall

[bmrboi2]

Originally Posted by ard

If you buy Carly, they will extort another 9.95 for the battery coding, as I recall

Yup. I did it. I've used it to register a new battery for a few of my friends.

[noelskii]

Just looked at my battery and it is a CarQuest 94R70

PART NO: 94R70
CCA @ 0*F: 765
20 AH RATE: 80

Does this battery suck or what? Looking to replace it sometime this week...

My two choices are:

Bosch Part#: 49-850BAGM

AutoCraft Part No: H8-AGM

Both are around the same price... Any suggestions?

Thanks!

[Kostyan]

I found a great deal on a couple of batteries in H9 size, however, both exceed my stock battery 105 AH rating - they are both at 110 AH.

The subject has been casually covered in this and other threads, but wanted to revisit all pros and cons of getting a batter with a bit higher AH rating.

[josiahg52]

I was in the opposite situation. The AGM H8 battery I found was listed at C/20 95Ah. The AGM battery options cover 90 and 105Ah. I consulted with the battery manufacturer and they recommended I choose the 105Ah option, assuming of course that the BMW capacities are indeed C/20 capacities. Given the options and the relative standard use of such capacities throughout the industry, this seems very likely.

Not knowing exactly how the BMW IBS works and the exact strategies used, mathematically, at worst, using a battery with a higher capacity than the system expects means your battery will be chronically undercharged and that would certainly lead to a shorter life span. Likewise, a battery that is of a lower capacity than the system is set up for - as in my case - may experience a shorter lifespan but for the opposite reason. Ultimately, the actual effects will depend on the battery design and construction.

ETA: I find it interesting that the OP replaced his battery with a Interstate MTP-49/H8 100Ah battery and stated that it was the same type that the dealer had installed in the past. 100Ah is not an option so I wonder what the dealer did? Probably nothing special or extra and just picked the closest value.

ETA2: I looked in Carly and the battery capacity options are the same as those in the first couple of posts of the thread. Another interesting facet is a note in the battery registration window in Carly that says to choose the next lowest capacity if your exact battery capacity is not shown. I'm not sure of the source for that guidance. The Ah value is probably used to help determine state of charge (SOC) more than define precise charging profiles. I'd hope that an INTELLIGENT Battery Sensor would use voltage, temperature and current indications to determine when the battery needed charging and when to terminate that charge. For that reason, I'm probably going to choose the 90Ah option for use with my 95Ah rated battery.