my battery recently died on mine, I was given a home made trailer, and I loaded the 450i on for a short test run, I was busy, so I just left it on the trailer, a few days later when I went to unload, it turned over, but no start, so I walked away, next day, only click click click, I was at dealer for other reasons, asked when I could bring it in, they were not particularly busy, and said right now, I drove back home, hooked up my trailer brought it in, they unloaded it with their forklift, I was due for service anyway, worked out good, battery was original from 2015 model year