Bests & Worsts Reviews from Amazon

I purchased two of these, one for my daughter, and one for myself. They worked great. My daughter has not had a problem with hers at all. I went out to take some photos Saturday night, and I use my iPhone 4S and professional cameras. The battery on my iPhone 4S crashed and so I plugged in the jackery mini and it did not work. I was able to get my iPhone going again, thought the external battery was charging but then my phone crashed again and saw no indication that the external battery was charging. So I emailed Amazon to alert them to the problem, started reading through customer reviews and read one where a person was told by jackery to press and hold the power button (that activates the leds) on the external battery for a few seconds until it was obvious the phone was charging. I tried that with my battery after plugging it into the phone and it started charging. This info was in the instructions, but I found the instructions confusing, and since the battery initially worked without pushing the power button, I never noticed. Based on that review and others that had the same complaint as I did (led lights work but battery won't charge), I would bet that most returns of this product are unnecessary. So far very impressed, once this problem was resolved. Giving it four stars because I think Jackery should go to more effort to make this info clear, it would save them money and customers aggravation, but it probably deserves five stars. If both units continue to work well, I'll change the rating if I can.