Some customers have trouble with charging the battery. When we designed this system, we chose a micro USB charging port because it was very popular. Unfortunately, these connectors are very unreliable. The battery should charge in maximum 2.5 hours from 0 to 100%. The LED will be red while charging, and green when complete. Even if you have a red LED, that does not mean it is charging properly. If the connection is bad, it will be continuously restarting the smart charging system, and never complete.
So, if you have any troubles, try a different charging cable and charging block. No worry about too much charging current, the charging rate is controlled inside the battery.