I recently placed a new battery in my 2001 X5. I still have not isolated whether or not the cause of my battery issues were due to an old battery, parasitic draw or the alternator. I have 2 questions: (1) while I'm still researching whether or not I have parasitic draw is there a good way to keep a charge on my battery if it starts to go down such as a battery charger or tender. And which is the best one or the two. For instance should put it on a charger once a week for a few hours to maintain the charge... (2) when trying to use a multimeter on my battery how do I turn off the tailgate so I can get a proper reading without it knowing I'm doing it. I hope all this makes sense...