We are a two car family and the I3 at 75% charge would serve 90% of our needs. Since we have two cars, we don't require fast charging, a 10-12 hour charge time would not present any real problems for us, thus these questions. Does the I3 come with a factory provided slow rate, plug in the wall type charger or is buying a charger a requirement? Is charging at a slower rate better for battery longevity? Thanks so much for any and all of your help. Looking forward to a test drive one day here in the USA.