Answer  One battery per charge. It takes a very long time for the charge to take and it gets very hot also! Unit died in less than a month! I do NOT recommend it!   

Answer  I've used it to charge my earpiece but never my phone thus far. I have it more for an emergency and it has come in handy for the earpiece. It's also handy for having an emergency flashlight if I've forgotten one at home. The directions say to plug it in and push the button. I suspect if you need to recharge your phone again it will work a second time. It does specifically say it requires you disconnect it to change out the AA battery, but it's probably easier to work with it that way. You load the batteries at the button end.   

Answer  I got about 2 charges per battery .I used it up in the mountains so Ichanged batteries every 2 times charging.Once your phone is charged you unplug it to save your batteries.   

Reply  I had a little trouble my firt time with this. My phone was half charged when i added this item. I put in the battery, connector and plugged it into my phone. It started charging right away. after about 2 and half hours i unplugged it and my phone said that my battery was low and I needed to charge it. The phone went dead and I had to wait until I got home and plugged my phone into the wall charger. What did I do wrong?   

Reply  When my phone is getting low I plugged this in and it started charging but after maybe an hour my phone turns off and says that it needs to plug into a wall outlet and then no power. While this charger is plugged in I can use my phone just fine. i thought this was to fully charge my phone. Was I wrong?   

Answer  it works as a charger, does not charger the phone. if you run out of battery it keeps it charger til you can get to a wall charger or car charger. but it save me a few time. good buy