aland

In order to keep my battery from going dead when my 2008 528i is parked for a month or two, I was in the habit of connecting a float charger. This was really a nuisance since I don't have a garage.

So, I obtained a BMW cut out switch which was manufactured by Hella and evidently, installed in BMW's ( I think M series ) at the factory before they were shipped to the US and then removed upon delivery of the vehicle. I thought it would be a really cool idea to connect this cable and when I wasn't using the car, to just shut the battery off. I would only lose the clock, date, MPG's recording and radio settings. Evidently the seat and mirror memories are "hard memory" which wouldn't be lost.

So, questions. First, what would be a good installation rather than just coiling it up in the trunk? And, second, do you think there would be a voltage drop over the total 18' of cable which would confuse the intelligent battery sensor system? Of course, I could possibly shorten the cables. Third, is there an issue with constantly running the electrical system through the kill switch? It is rated at 100 amps.

I attached a photo of the cable.(click to enlarge )