Charging and stability in the PowerPackis improved in updated versions of the firmware (the software that controls the PowerPack). If you experience problems with charging, update the firmware.
For instruction of how to update the firmware, please go to the question in this FAQ or to the manual in the smartphone app.
We recommend using a 2 Ampere charger for best and fastest result when charging the PowerPacks. A weaker charger like 1 Ampere or less takes longer time and it can in rare occasions be necessary with an additional charge to reach 100% charge. This behavior for weaker chargers will addressed in future updates.