PowerIQ: Minimum power for Bluetooth Headphones

What is the lower bound of PowerIQ’s variable charging range?

Anker chargers are capable of fast charging phones and tablet with high amperes and voltage.

However, the smaller batteries on bluetooth headphones typically require charging rates under 500mA. Otherwise the battery will deteriorate faster rendering the device useless.

How low can Anker USB chargers go?

Is there a specifications sheet with this information?

After more browsing, it looks like this is the answer:

Devices have builtin resistance designed to limit the input wattage to design parameters.

http://forums.androidcentral.com/ask-question/534912-i-think-anker-power-iq-technology-pure-bs-here-why.html

Consider PowerIQ to be just like any other USB charger, you have a max output of 2.4A (I believe or 2.1A) and everything below that is available to whichever device desires a lower input. The one thing it won’t switch is the voltage…so if you have some weird non-standard USB powered device that takes a lower input you might want to use only the charger that it comes with.