I've had this for about a month now, and it's pure garbage.  Everything worked fine at first.  After about 2 weeks, I noticed that the original battery that came with my phone couldn't hold a charge like it used to, so I started using the backup battery almost exclusively.  Next, the cord that you plug into your phone didn't always recognize that it had been plugged in.  I thought it was my phone at first, but I tried plugging in the original charger that it came with a few times and it recognized it easily.  Now I have to play a little game of "What do we have to do to make the phone recognize the cable today?" whenever it needs a charge.  Even after I've found the place that it finally recognizes and put it down, I'll get up in the morning to find that the phone hasn't charged at all and is now dead.  Avoid this product at all costs!  There must be a better brand of this product out there somewhere....