Get a foxwell NT 5xx scanner it can battery register as well as a a few dozen other things that are critical to proper maintenance of an X5.

If you have a volt meter with peak reading you can estimate the current draw on the starter by measuring voltage drop from cigarette port to to b+ jump point under the hood while starting. I've typically measured about 0.75v drop for a summer time start

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