When I received this, it showed a capacity of 3 stars. I charged it to full (in a couple of hours), and then tried it on my iPhone 4. After 2.5 hours, it charged from 14% to only 59%, and then the capacity ran out, and it stopped charging.
It's a female/male pass-through design. So, you can plug in your power source at the bottom (female), or plug the top into your iPhone/iPod unit (male). The top (male) connector has a removable cover.
Load:
I'm going to try charging it fully, because I've had other issues with the first cable that I used to charge this. Then, I will try charging again and see if a full charge puts the battery higher than the 59% of my first test. I will update my review when I get those results.
Design (broken connectors):
I've read some reviews and suspect people are breaking their connectors. Although there's a protective plastic piece for the "male" end of the charging unit, when it's plugged into an iPhone 4 and laying on a flat surface, the iPhone/charger doesn't sit flush. The bottom half of the iPhone is elevated 1/4 inch above the surface, and the charger is not level either. If you were to press the Home button, or otherwise work on the iPhone while it's plugged in, you would risk snapping that little connector. It seems solid enough if you're not doing anything. So, with some precaution, you could avoid this by either not using your device, or holding the sides of the unit while pressing on it.
Operation:
The 4 led lights identify the capacity. They seem to come on if you have it plugged into a power source (male or female), or when pressing the button on the unit itself. The "full" led at the bottom probably only comes on after the 4th capacity is lit up, and it has a full charge. I will update when I find out for sure.
Pressing the button shows the capacity led's. It's not necessary to press the button to begin charging, it will begin automatically.
Cases:
I have an Otterbox defender case, and I had to remove the iPhone from the case in order for the device to be recognized. It looked like it was fully inserted, but it wasn't. Removing the case was the only way to get it working.
Testing:
I plugged the unit in, and opened Battery Doctor to perform a full cycle charge. I left the app open and running for the first portion of the test, and then turned off the device for the last portion of the test. All other apps were closed, and I did not use my device during testing. My battery started at 14% and ended at 59%.
0:00 14%
0:01 15%
0:02 16%
0:03 17%
0:04 18%
0:07 19%
0:10 20%
0:13 21%
0:14 22%
0:16 23%
0:21 24%
0:22 25%
0:23 26%
0:24 27%
0:25 28%
0:35 29% * Turned of app. Capacity led's: 2
* At this point, I would sporadically turn on the device, check the battery level, and turn it off*
0:43 34%
0:50 34%
0:52 35%
0:55 39%
1:00 39%
1:05 44%
1:10 44%
1:20 49% * Capacity led's: 1
1:30 54%
1:35 59%
2:00 59% * Capacity led's: 0 Charging stopped automatically.
---Update: Dropping this from a 3-star review to a 2-star review.
After fully charging the portable charger unit (with a portable speaker/charger, not just a cable this time), my second attempt shows that it will not fully charge to 100% in 2-hours as claimed.
I started my second test at 34% battery with a "full" charger (only 2nd time used). After 1 hour, 20 minutes, it's peaked at 63%, and the capacity led is at 1, meaning it will be dying soon.
Too bad, I wished this would work with a full charge, and to give some credit, it does "partly" work. But, don't expect the 100% charge that is falsely claimed. I was hoping to order another one, but now seriously considering if I should just return this one, even though it was only $6. :-/
I'm using an iPhone 4.
---Update: Dropping this to a 1-star review.
After fully charging again, and testing again, it charged from 19% to 69% in 1 hour, 40 minutes. It seems it will never get the 100% charge as promised.
In addition, I had the issue where it wouldn't work at all! After letting it charge overnight, I tried to plug it into my phone and nothing happened. I reinserted it several times, at various angles, etc., and nothing happened. Even pressing the button did nothing. I then set the portable charger on the boombox charger I have and the 4 led's and full led lit up, then immediately pulled it off and tried it and it started charging.
This is not acceptable. You will not be able to do this when you're away from your charging source. In other words, it's unreliable and has a good chance of not working when you need it to!
After owning this only one day, it failed on all tests, so I'm returning it. It's not even worth the $6 given that it won't perform it's function when I need it to, and doesn't deliver the 100% charge as promised.