Q: Will the PowerPack 10K automatically turn off if the current draw is very low? I’m trying to use a battery pack with an Arduino board, but it auto powers off after a certain amount of time.
A: Yes, the PowerPack 10K will auto shut off in 30 seconds if the current draw falls and stays below 50 mA or so. To the best of our knowledge, pretty much all battery packs on the market that output through a USB-A port will have to face the same situation. To conserve battery, battery packs want to go to sleep when they finish charging a device. The USB-A specs do not offer a method to signal completion of charging, so battery packs usually implement a cut-off current below which they would deem charging is done.
We offer a partial solution to this: On your ZMI PowerPack 10K (Model QB810), you can double-press the side button to invoke the low-power charging mode. You'll see the four LED lights start to flash on/off in a circular pattern. In this low-power charging mode, the battery pack will ignore the current threshold for 2 hours. This duration is typically long enough to charge smartwatches, BT headphones, and fitness trackers, and should power your Arduino for 2 hours. To exit the lower-power charging mode before the 2-hour timeout, you can just press the button one time.
If you need to power your Arduino for longer than 2 hours, you could try to make sure the current draw is greater than 50 mA plus some buffer (say, 100 mA total current draw). Alternatively, you may consider getting a battery pack with a USB-C output port and a USB-C to Micro-USB cable to go with it. The USB-C specs do not allow the kind of current threshold based auto shutoff. When you plug the USB-C to Micro-USB cable into such a battery pack, you will be able to have it on with or without a load connected to the Micro-USB connector.
Good luck with your Arduino project. Have fun tinkering!
PS: The above discussion carries over to the Raspberry Pi and other IoT dev boards.