Is it possibile to charge my laptop from arduino usb connection?
I am building a robot with a laptop and arduino and i have to add battery capacity to the laptop
In a word - no. Your laptop is a USB host - it powers other devices. Have you thought about powering the laptop through it's normal power connector? typically 12v - 20v. It's certainly possible but will need some work as your laptop could be using anything up to 120w.