I had this problem and was at the point of giving up and buying another solution. Even buying a wifi repeater good enough to watch a hi def movie in the garage made no difference. The problem is that the micro USB connector is of poor quality, so the unit loses power when it vibrates every time the door opens and closes. There are two short term solutions: 1. Buy a high quality USB to micro USB connector. 2. Or what a really cheap person like me does: tape the connector in tightly with insulation tape - I have had absolutely no problems since doing this.
But the proper solution is for Garadget to use a higher quality connector. (Garadget, I hope you see this - this saving of a few cents is ruining the impact of a wonderful product.