This problem has been answered a number of times for many different cell phones and tablets. Some will never work, others only need a usb cable. Start with a search of this thread. If that doesn't work, go to the Geek Out 1000 & 450 threads.
I don't know any details about your LG but there are a number of issues you may have to deal with. If you are really lucky, simply plug it in and the LG will supply enough power and it's usb implementation and Android OS implementation will talk to the V2. If there is not enough power, you can solve that with an external 5v dc source and a splitter cable which isolates the 5v pin on the LG. The 5v dc source can be a battery (like the one you use to charge your phone; e.g., a VAANs Power Bank, etc..) or a 120v ac to 5v dc power supply (these vary from wall warts of various quality up to linear power supplies). Finally, as with some Apple devices, you may have to add a 2 port usb hub like the "plugable Hi-Speed USB 2.0 Hub" (try Amazon).