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by chendragon
2420 days ago
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Based on my past experiences I find that "x" amps of rated charging current often is more of a cap on the total input current. Samsung devices (this is a Note 5 btw) limit charge current when the screen is on, probably to reduce the heat generated by the device (though I would much have preferred using actual SoC and battery thermistors to dynamically throttle this), but under load the device seems to be able to pull power from the charger as needed. When the screen is off, the battery charges at full current but beyond 80% usually slows down below the rated (Entering CV phase from CC) However, the battery chargers on all devices might be set to lower than 4A or whatever the rating is, and without the system load it won't hit the full input current. Also note that typically devices (esp. Apple) expect 4.8V or so to keep increasing current draw. Most cables are quite thin and unable to meet this requirement, dropping under 4.7 at 1.5-2A. The charge controller will likely then throttle the current to stay above this threshold. I have had Anker PowerLine (2?) USB A to Micro B cables that were able to handle 4A (rated 2.4) before falling to 4.85V (tested with 5 port usb charger modified to bypass load side switches so theoretically 12A output). Neither connectors, cable, or other components became hot or warm. Most other cables can barely deliver 4.76V at 1.7 ish amperes. This probably correlates with parent comment's experiences. |
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Anker's PowerIQ circuit seems to be wired to do exactly what you say, and looks like a modern CC/CV PWM LED lamp driver: switches to CV and lowers duty cycle to maintain intended max output once it crosses the voltage threshold (which could indicate a runaway thermal overload).
Apple's designs are baffling to me: the worst cables I've ever seen. Take the newest phone, the 11 Pro, and take their beefiest charger (I think this now comes with the phone? Is this the same one as the current iPad iterations'?)... and compare the stock cable to an Anker Powerline 2 or 3: an immediately visible difference in charge speed; and then do the same with a PowerIQ 2.0 charger w/ stock vs Powerline 2/3: an even BIGGER difference.
The hell, Apple?!