Bests & Worsts Reviews from Amazon

My main reason for buying this Jackery Bar 5600mAh Portable Power Bank is because it advertises '2.1A Output'. I already own several Power Bank units in the 5000-5600mAh range, but none of them is powerful enough to satisfy my Barnes & Noble NOOK HD+ Tablet which demands 2A of charging current (if it cannot get 2A, it falls back to 0.5A instead). This Jackery power bank unit, however, is able to charge the Nook HD+ at full speed without any problems. The Jachery power bank has an aluminum casing that looks elegant and feels sturdy. It is slightly larger and heavier than my two other power banks units with identical capacity ratings: the EC TECHNOLOGY 5600mAh and the PowerBot PB5600. See the photo I unloaded to 'Customer Images' section for size comparison. I tested the battery capacity of this power bank unit, by connecting a 5-ohm power resistor to its USB port. The unit is able to produce a well-regulated 4.92V at 0.95A (output power=4.67W) for 254 minutes. The total output energy is therefore 19.8Wh, which is consistent with the '5600mAh' capacity rating (3.7V * 5.6Ah = 20.7Wh, minus power conversion loss). In contrast, my other two '5600mAh' power bank units did not perform as well: - The EC Tech unit delivered total energy of 17.8Wh (10% lower) - The PowerBot unit delivered 15.0Wh (24% lower) See the "Output Power vs. Runtime" chart I uploaded in Customer Images section for details. Some other things you should know about this product: - The USB power does not turn on automatically when you plug in a device. You need to press the white power button on the side to turn it on. - The 3-bar battery status light only comes on for 5 seconds before turning itself off, even though the USB power is still on. Just press the white button again to check the battery status. - When the battery is nearly exhausted, the status light comes on and starts blinking. - The instruction sheet says each of the three LED bars represent 33% of battery status, and blinking LED means less than 10% of charge left. Based on my testing, this seems to be an accurate description. Most other power banks I tested have highly non-linear status lights, so for example if only 1 LED out of 4 is on, the battery could be anywhere between 10% and 50%. - To recharge this Jackery Bar's internal battery, you just connect it to an USB power adapter. It takes about 5-6 hours to recharge if your USB power adapter can supply at least 1A of current. If you recharge it from a computer's USB 2.0 port, the current is limited to 500mA, so now it takes about 12 hours to recharge. - The LED flashlight is turned on/off by two quick clicks on the power button. It is nothing to get excited about, though. The beam is dim, greenish and unfocused. On the up-side, it claims a really long runtime of 450 hours. CONCLUSION: The Jackery Bar power bank is well-built, and it delivers the advertised output current and battery capacity. The only drawback is price, as it is currently priced about 60% higher than my two other 5600mAh power bank units. But since I really need the 2A output current for charging my Nook HD+, this is the smallest and lowest-cost power bank unit that works for me.