Nugenic B11 Bluetooth Microphones Best Offer

My favorite pair of (cheap) Bluetooth headphones recently lost their ability to hold a charge. Incidentally, I decided to take them apart and investigate the components. As one might expect, the headphones consisted of two small audio drivers, a lithium-ion supercapacitor (rechargeable battery), and a Bluetooth system on chip (SoC). Traditional wired headphones consist of a pair of audio drivers and a plug that connects to a preamp device (cell phone, iPod, stereo, etc.). Bluetooth headphones additionally require conditioning circuits for batteries, amplification, and signal processing. These circuits are necessary to reproduce the original audio signal that is sent from the device, which is subsequently decoded on the headphone side and amplified for human auditory enjoyment.

The headphones used here are the They operate under Bluetooth 4.1; they have two audio drivers; a microphone for talking; and a button module with headset, hands-free, and audio/visual remote control profiles. The device battery capacity is 110 mAh and the device uses a classic micro USB plug to charge. Below are several marketed photos of the headset. 

Disassembly

The first thing I noticed when disassembling the device was the deliberate manner in which every component was placed. It was not easy to dislodge every component, and as a result several elements were damaged or destroyed. Below is an image with the basic components displayed. You can see the connecting wires, the soft gel tips, the speaker casings, the plastic button module, the microphone grill, the battery, the signal processing circuit, and the micro USB charging port. 

Speaker Components

The most basic components of a speaker are the voice coil, magnet, and cone. The voice coil oscillates back and forth due to Faraday's law of induction because of the magnet and an applied alternating current. This oscillation, when connected to the cone, produces pressure waves by moving air at the frequency of the applied signal. This is the basic functionality of a speaker and is the functioning mechanism behind the Bluetooth speakers in each earbud above. 

The peculiarity of the earbud speakers lies in the top cover. The top cover not only blocks part of the speaker cone, but it also has a long thin channel that leads to the grill. This is an interesting design choice. Possible issues could arise in performance because of the geometry of the channel. There may be reflections, dissipation, standing waves, etc. that could produce unwanted audio profiles.

Battery

The most interesting discovery in this disassembly was the use of a supercapacitor. I was not aware that supercapacitors were utilized in cheap devices, let alone Bluetooth headset devices. The capacitor had a signal conditioner atop it, likely for voltage or current regulation. I am not completely familiar with supercapacitors, so I will leave this aspect of the investigation alone, however, I wonder if the label is true or if it's just a regular li-ion battery. The reason is that supercapacitors are supposed to retain their charge for hundreds of thousands of cycles, and this one went from 8 hours to 2 hours in a little over a year. And I only charged them two times a day. This means that after roughly 1200 charges it lost 75% of its ability to hold a charge - I think that sounds more like a li-ion battery. However, there may be something at work that I am not familiar with, i.e. self-discharge, heat damage, circuitry leaks, which could have contributed to this seemingly short life span