PC USB Cable for Garmin Edge 605 705 NUVI 265WT 250W 2555 2555LMT

hello in this video i want to talk about the garmin nuvi satnav in my case it's the new v2599 now the specific problem i've had with this is trying to um power it and use it with just a mini usb cable now why would i want to do this well let's say my original 12 volt adapter has failed or i don't have a 12 volt socket in the car or i want to just power it from a patchy bank for whatever reason what i found is if i use a normal mini usb cable and plug it into the little ports at the back the other end into a battery bank for example it'll go into pc sync mode and it won't really let me get much further so i found this strange because the original garmin 12 volt adapter is nothing more well nothing more on the face of it than a simple mini usb plug which goes to the 12 volt adapter so what's so special about this why does this work and yet a normal um mini usb cable won't so what i did is