Having to do that relearn when you're away from home doesn't always work because you're battery will most likely go dead before you complete it. When i did my relearn instead of a battery charger i just used my other car and hooked up the jumper cables and let it run until i was done. Unless you know the person very few if any strangers are going to let you sit there with jumper cables hooked up to their car for a 1/2 hour.