I fitted a brand new battery to my Roadster and it still drains to fast I would expect a new car and new battery to sit on a driveway or in a garage unattended for a couple of months without starting issues.
Given that the S5 is a new car it shouldn't be suffering age related battery problems.
Sitting on a battery conditioner or isolating the battery isn't an acceptable answer, more work needs doing at the factory to get to the bottom of this.
The typical battery draw of an immobiliser and alarm is 150ma. Multiply that by 24 hours gives 3.6 aH times 14 days is 50aH. Which is more than enough to take a car battery below the level at which it will start a big engine.
And that 150ma draw is common to a lot of cars and bikes. Just google current draw car alarm and you will see dozens of posts from all sorts of car make forums raising exactly this issue.
I would be really annoyed if I had spent upwards of £100,000 on a new car and I had to charge the battery after every run out!!
You are far more likely to have this issue with a £100k car. After all, would you bother with an alarm on an old Fiesta.
Its completely unrealistic to think that alarms and immobilisers and trackers not to mention things like clocks and keyless entry etc can be run without constant current draw. How can your alarm work if it isnt powered up?
And you arent charging your car after a run unless your alternator or battery are duff. What you are doing with the Optimate is powering the alarms etc whilst the engine isnt working.
