I think you can code out the charge when coasting. Unless you drive mostly short drives and plug in when home I doubt you'll be doing the battery any favors disabling the IBS.

I thought about doing that but then I'm a big fan of the mog I get and have no negative impact from the wildly changing voltage.

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2011 E70 • N55 (me)
2012 E70 • N63 (wife)