Troubleshooting Bluetooth Digital Alarm Clock Speaker

Troubleshooting Bluetooth Digital Alarm Clock Speaker 

While using this CLOCK BLUETOOTH DIGITAL SPEAKER model GT-10 which I bought from a friend. 

I noticed that there is a problem with the battery charging LED. It took me whole day to charged the CLOCK BLUETOOTH DIGITAL SPEAKER but it never reach 10% of the battery capacity.

My first prediction of the problem is that battery drained or dead battery. So, I bought a rechargeable 3.7 volts battery from the ELECTRONIC SUPPLY and disassembled the the DEVICE. See the pictures below.