The sparking is normal, this means there is at least some voltage in the battery. When you go to start the car, do you at least get a click of the starter soleniod, or is she completely dead? Do you have a basic volt meter? If you do check the voltage of the battery with the car running, presuming you get it jump started. With the engine running, you should be getting 14V on the battery terminals. If you are not getting this, you alternator is shot. With gasoline cars, everything is powered by the battery which is constantly being charged by the alternator. Once the alt. falls behind the electrical demand of your sparkplugs, power features etc. the battery has to burden that load on it's own. With all the electronics your car has, it wouldn't take long to kill a battery. If you don't have a basic volt meter, you can buy one at any autoparts store for $5-$10.

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1999 MB SL500 (110,000 mi)
2004 Volvo V70 2.5T (220,000 mi)
2014 Tesla Model S 85 (136,000 mi)
MBCA member