2008 BMW X5 electrical system problems

I noted that the vehicle was not running properly so I took the SUV into an authorized BMW service center to be inspected and repaired. I was notified that the vehicle had experienced a burned up wiring harness from a short circuit to the disa valve on the engine. I was also notified that cylinders 1, 3 and 5 had failed ignition coils, which was the reason for the poor operating performance. I was also informed that the vanos valves were sticking and may need replacing.

My 2008 BMW x5 is reporting high battery drain and it's only 13 months old with 5,000 miles. The dealer states the issue is because the vehicle is not driven at least 25 miles a day. If this is a requirement to owning the vehicle it was never mentioned when I purchased the vehicle. My own research on the internet indicates this is a well known problem by BMW. Yet the only solution offered is to replace the battery prematurely as it fails or hook the battery up to a trickle charger every night.