just brew it! wrote:
So the mAh rating on these things... assuming the vendor is being reasonably honest, is that measured at 5V? Or is it at nominal cell phone battery voltage (3.7V-4.2V)?
I always assumed they were at 5V, since that's what they are providing via the USB ports. I guess I'm not surprised some may...massage
that rating a bit.
With the various quick charging standards the voltage at the port can go significantly above
5V too. And not all phone batteries are 3.7V. So really it only makes sense
to quote watt-hours, not mAh. Of course since it makes sense, we don't do that...
Captain Ned wrote:
If you've got an Android phone, the Ampere app is a godsend. The cheap paid version gives you charging rate in milliamps, voltage to 3 significant digits, maximum source current from the charging source and, most importantly, battery temp. I'm plugged in to a 4-port USB 3.0 hub living in a 5.25" bay using an Anker USB-A to USB-C cable and Ampere shows me a max charging current of 1500 milliamps and a battery voltage of 4.401V. USB hub is plugged into USB 3.0 header on an Asus Z97-A.
Using this app I have discovered that a Nexus 6P on USB 2.0 (500 milliamps max charge) will be in a discharge mode even when plugged in if the screen is lit (Ampere also shows outgoing current draw). When you plan for a 4 hour trip through the security line at O'Hare (like last year) and instead get a 4 minute trip, one has time to analyse things one never thought to analyse until faced with the crushing boredom of an airport terminal. Worst part is that all the bar seats were taken.
Cool, I need to look into that. I do have a pass-through USB dongle that tells you voltage, current, and total power transferred thru the port, but that app sounds like it gives more detail since it knows where all the power is going inside the phone.
Does it require a rooted phone?