Most people don't want to have to think about USB power delivery handshakes and resistors. And they don't want to research what they need to look for in a USB 3.0 cable vs that USB 2.0 cable they bought years ago.
Anker seems to be technologically on the ball, but above and beyond that it's a "we promise not to @$^# up the accessory we sell to you" guarantee. Which the Chinese fly-by-nights seem incapable of grasping.
I did find the packaging a bit ostentatious for a USB charger. A plain corrugated cardboard box would have been more appropriate for mail-order, though I can see why they might want to "steve-job" the packaging for retail.
You do messy stuff there, like take off your winter boots, or leave your bike.
No, total agricultural land is less than 1 billion of a total of 2.3 billion acres.
Getting Anker products is so much easier and quicker than the old way of trawling through pagefuls of cables trying to find those that appeared spec compliant (thanks, Benson!), reasonable quality, and don't try any scams like "Fully USB 3.1 compatible" thanks to USB 2.0 fallback.
This comment doesn't make sense in the context of the battery pack being used as a charger. Are you talking about when the battery pack is charging?
(for clarification, the principle is V=IR, you could hook a 5V incandescent lightbulb or LED up to that same 1000A supply and it would only draw I=V/R (Current = 5v / series resistance). Yes, there is silicon controlling the battery, but at the most basic level, if the series resistance of all that plus the battery is 5 ohms, it will only draw 1A)
Edit: math fail
LEDs use constant current power supplies with variable voltage, and I've seen some hybrid designs with exotic combinations of constant current / constant voltage regulation.
See, for example, this design note from Linear Tech: [0] which describes a 20V adapter, analogous to OP's 5V USB 'charger', that can provide 2A (40W total) to the laptop. If the laptop battery charge management IC says that the battery can use up to 2.2A at 12.6V = 27.7 W, but the laptop computer is using more than 40-27.7=12.3W, it will reduce the charge current to the battery to avoid damaging the 20V 2A adapter. The problem that pdelbarba's USB battery packs are solving is that they can be plugged into various adapters - perhaps a port on a laptop limited to 500 mA, or a 1A 'phone charger' or a 2.1A 'tablet charger'. Some manufacturers solve this by adding resistors to their chargers so that the device can sense the resistance and know it can use up to 0.5, 1, or 2.1A. But everyone uses different resistors.
So Anker does a functional test rather than the electrical equivalent of user-agent-string parsing to set the current limit.
> unless the charger could somehow sense the resistance of the charging cable and compensate for the voltage drop, then the output would be >5V at the charger, but =5V at the end of the cable. That would take some sorcery I'm not aware of though.
That's pretty standard for lab power supplies. It also is used in precision metrology with sensors like load cells. All it takes is a pair of non-current-carrying wires to sense the voltage at the device. The current-carrying wires experience a voltage drop, but the sense wires are only feeding into high-impedance measurement inputs. This is known as a Kelvin connection.[1] With a device that takes an excitation voltage, you'd use a 6-wire connection.[2]
[0] http://cds.linear.com/docs/en/design-note/dn194f.pdf
[1] https://en.wikipedia.org/wiki/Four-terminal_sensing
[2] http://loadcelltheory.com/LoadCellSupportTheoryPDF/ShuntCalR...
Yes, I suppose it's incorrect to think of the charger as pushing current; but with a resistive load, with LEDs, with raw lithium cells, most batteries, and with most loads in general, the current can be expected to increase as the voltage increases. And some power supplies regulate output by current rather than voltage. I didn't know that about lab power supplies, very interesting!