Does anyone know if the recommended factory procedure would be to apply 12v to the system prior to disconnecting the main battery? To prevent E/EPROM issues and reset sensors, etc?

I know this could make for an easy short situation in the trunk...

I can only imagine the charging post under the hood directly is a direct path to the battery (or alternator, either way) so no charging electronics "between" the jump battery and the vehicle battery.

I think there's more risk with trying to keep the car powered during the swap. The only odd thing I found after a battery swap was a steering error that reset after I turned the wheel lock to lock. As far as I recall, all settings were retained.

I've been having low battery charge problems on and off since last December on my 2007 X5 3.0i, which was about 3 years after I had the battery replaced at my BMW dealer. I didn't think it could be a bad battery after only three years, esp being the BMW OEM battery. But last week I was having the water pump replaced at an independent shop, they also did some other checkout of the car, and said that no battery had been registered to the car since it was originally sold in 2007. In other words, the dealer did not do ANY registration or coding when they replaced the battery in 2012, but still charged me $600!

So rather than go to the dealer again, I ordered the Interstate MT5-49H8 battery from a local shop and installed it this weekend. Took all of 10 minutes, if that. I haven't registered it yet though. Should I really register it, given that the car thinks the original battery is still there, going 9 years old?

Also I have a USB K-DCAN cable I ordered off Amazon, it came with a disc that appears to have INPA software, but I'm not sure it is installing correctly on my Windows 10 laptop. I was wondering, the Carly app looks more user-friendly and claims it can do registration. Can the Carly app for Android work with the USB cable if I connect the cable to my Android phone with a USB OTG adapter? Or could the Carly app work with a Bluetooth OBDII adapter (I use one with Torque app)? Or does Carly ONLY work with their Bluetooth dongle or USB cable that they sell?

Yes You should really register it

also, neither EPROMs nor EEPROMs lose their state when powered down. an EPROM would require UV light to be de/reprogrammed and an EEPROM needs field electrons applied in a specific manner for the same purpose. both are non-volatile memory, the hint is in the ROM-part.

Have used Carly app with USB K-DCAN on my nexus 5. Actually works better than my generic Bluetooth dongle. I have not used the battery registration though. But I don't think it should be a problem.

Thanks.
 

Great instructions by the OP. Had low battery warnings and increased battery discharge warnings in past month as it's been getting colder in 2011 X5 with original battery.

Just got a perfect fit 92Ah Duracell AGM battery from my 35d from BatteriesPlus.com (10% off coupon code) for $200 and installed without a glitch. Make sure you get the same battery size and type (AGM vs flooded lead acid) as what you had before--mine was group 49 AGM. All you need are a couple of standard metric sockets, socket extensions, and a Phillips screwdriver to remove the old harnesses and brackets--took about 30 minutes taking my sweet time.

After I followed the instructions using BMW's INPA software for battery REGISTRATION (takes about 2 minutes going over the menus carefully as posted by OP), I was good to go. The BMW INPA software I got eBay for about $30 shipped with a OBDII KCAN-DCAN BMW USB cable (obdinnovations.com)--which you can use to code your car as well for other feature options (although a bit finicky to set up).

How reliable is the Low Battery warning message? I have a 2007 4.8i and I can definitely hear a difference in starting with the cold weather.

I knew battery was low, 577a after charging all night, but Sunday morning convinced me to get a new one. It almost didn't start. No warnings though. I barely drive the thing. Picked up a Bosch 92ah from Pep Boys. Waiting til I can find time to get it coded to put it in though.

I installed that exact battery today. Pretty much the same battery down to the indentations. OE was rated @ 900 CCA, Exide is 850 CCA at 0 F. Wouldn't make any difference here in southeast TX. Both 90Ah, and 160 RC. OE was also an Exide.

Used ISTA to register it. Highly recommend it. I got it for $159 shipped from Rural King. It comes with free replacement for 4 years.