I have turned my raspberry pi B+ into a wifi repeater (i.e running 2 usb wifi keys). It runs on a portable power bank now. So I am limited by the lifetime of the battery, approx. 3 hours.
I already have a 3 meters USB extension cable and couple of others of 1 meter, but none of the combination I have tried have allowed me to power up the raspi at no less than 1.5 meter from the power plug.
What's wrong with my cables ? What are the required spec for this to work at 3 or 4 meters ?
My USB charger outputs 5V/2A