Most likely it will work. I had tried using a phone plugged to the charger, but with the battery taken out. A battery pack is just another power source like a charger. However, if you want to be doubly sure, you could:
a. borrow a battery pack from a friend and try.
b. bring the phone to a shop that sells battery packs, tell the sales person that you would like to test before you buy.
Last edited by chan.sk; 18th January 2014 at 12:07 AM.