> The "mobile" part ceases being true when their battery is only sufficient to allow them to be mobile for the duration of an entry-level delayed road trip. No

> The "mobile" part ceases being true when their battery is only sufficient to allow them to be mobile for the duration of an entry-level delayed road trip. Not that this is more than a patch for poor battery life, but even if you have a long-lived battery but sometimes forget to charge your phone until it's dead, it's worth being able to charge your phone on the road. GPS drains the battery significantly faster, so you can be doubly-screwed if you're using your phone for driving directions and the battery runs out -- no directions, and no way to call for help! It's pretty easy to find a cigarette lighter plug with a USB port, fortunately.