Why Does the Battery on the PowerPack 20K Drain Even When My Apple Device Is Not Connected?

Q: When using a USB-C to Lightning cable, the four LED lights on the PowerPack 20K keep flashing even with no device connected to the other end of the cable. The battery is draining while this happens. Is this an issue?

A: The PowerPack 20K is behaving this way because of the constraints of the USB-C standard and the way Apple's USB-C to Lightning cable is designed. When using a typical USB-C to USB-C cable, the lights on the PowerPack 20K will stop flashing automatically after some time if no device is detected to be charging on the other end. However, with Apple's USB-C to Lightning cable, the PowerPack will function differently.

1. The USB-C standard has defined mechanisms to allow a power-drawing device (such as a phone, tablet, or laptop) and a power supply (such as the PowerPack) to signal one another. These include: when power is needed and the power supply should wake up and provide power, and when power is no longer needed and the power supply can go to sleep (to conserve power). This is why you see the PowerPack going to sleep while the USB-C cable is plugged in but without a load (such as a phone) attached to the end of the cable.

2. Apple's USB-C to Lightning cable is different than the USB-C to USB-C cable in that the former is itself a load. There is a proprietary IC chip made by Apple embedded in the Lightning tip of the cable. Moreover, there is no perfect way to map the pins of the USB-C connector to the Lightning connector. What we know as the USB-C to Lightning cable is essentially a "hack" by Apple to support USB-C power supply. You might wonder why iPhone's stock Lightning cable doesn't have this problem. That's because battery packs typically implement a detection mechanism to monitor the current (amperage) drawn by the device and will shut off and go to sleep if the current draw falls below a threshold (somewhere between 50 mA to 100 mA). The reason this minimum current based rule has not been applied to USB-C is because that would have violated the USB-C specs. In comparison, the old USB-A standard does not stipulate this area, leaving more freedom for vendors to define their own hacks.

3. The behavior of the PowerPack, when used with the USB-C to Lightning cable, is commonly seen among USB-C power banks. The Lightning tip is a load by itself, even if no device is attached to it. The battery pack cannot just turn off, because that would be off-spec. When a power supply is off-spec, a whole range of compatibility issues will arise when the power supply tries to work with other devices that do follow the USB-C specs.

A solution to the problem: Unplug the Apple USB-C to Lightning cable from the PowerPack when you're not charging your iPhone or iPad. Starting with the 2018 iPad Pro, Apple has begun switching to the USB-C port. This problem will be a thing of the past after Apple completes the transition from the Lightning port to the USB-C port.

 

Apple USB-C to Lightning cable PowerPack 20000 PowerPack 20k USB-C

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