Replacing Battery in TaoTraonic TT-BH052 Bluetooth Earbuds' Case

My teenage son misplaced his beloved TaoTronic TT-BH052 bluetooth earbuds in their charging case somewhere in the house. We eventually found them coming out of the washing machine with a load pants.

The earbuds themselves are water resistant and were even connecting to his phone while the wash was running, but the charging/carrying case was not so lucky.

One feature he uses a lot is the ability to charge his phone from the case as it has a 3,350 Ah battery in it. After the trip through the wash, the case would not charge, even though the 1st LED would illuminate. Also, the earbuds would not charge even when the micro USB was in place. Once the earbuds used up their remaining charge they were useless too.

The newer model bluetooth earbuds from TaoTronics do not include the ability to charge other USB devices from the case, so upgrading to an available model wasn't an option. Also, to help our planet and pocketbook it is better to repair something than replace it.

Supplies

Small Phillips head screw driver
Replacement 18650 Li-ion Battery (see Step 2 for details)
Soldering iron and solder

Step 1: Disassemble the Carrying/Charging Case

The charging case is made up of 5 components:

plastic base
plastic lid
plastic earbud holder
circuit board
battery

Disconnect the charger from any USB cables, remove the earbuds and keep them in a safe place.

Carefully use the lid to pry open the back of the case, then you can separate the three plastic plastic parts. It helped that the lid had popped off previously, so I knew how the assembly worked.

Be careful about how far you separate the earbud holder from the base as the battery is firmly attached with double stick tape.

Unscrew the circuit board board from the earbud holder, it is held on with 4 screws. Make sure to note the location of the 1 screw that does not have an integrated washer so that you can reassemble it correctly later. The washers should not touch any of the circuit traces or pads.

Step 2: Desolder Battery From Circuit Board

Carefully desolder the two battery leads from the circuit board. Note which side the red (+) wire is connected to as the circuit board does not appear to be labelled.

After removing the battery, I was able to detach the extra sticky double stick tape that is wrapped around the battery. Save this to reuse with the new battery. The battery is an 18650 Li-ion 3.7V 3,350 mAh battery. I happened to have another 18650 cell around the house from a rechargeable LED flashlight so I used that.

You can use any capacity (aka mAh) 18650 battery for the replacement, but don't be fooled by the >9,000 mAh batteries, they are too good to be true. The one I had is 2,000 mAh so it has about 2/3rd of the capacity which is plenty for the earbuds and 2 full charges of an iPhone.

The battery I had did not have leads and I couldn't find any that I could easily purchase with leads, so you will likely have to solder leads onto the battery.

Step 3: Clean the Circuit Board If Necessary

As the case was completely submerged in soaping water while powered by the battery, there is a good chance some form of electrical bridges formed between the components on the circuit board.

The connections around the pins for one of the earbuds showed some evidence of temporary short circuits or deposits between the contacts. The IPA will dissolve any bridges (short circuits from the soap/water/salt) and then evaporate. I learned this trick recovering an old iPhone that went for a swim in my pocket.

Using 90% Isopropyl Alcohol (IPA) and an old toothbrush, gently clean away any salt bridges or other problems caused by the water. As long as a component did not explode or get fried in the bath, the circuit board should have survived.

Allow the circuit board to dry completely before moving onto the next step. A little compressed air can accelerate the process.

Step 4: Connect New Battery to Circuit Board

Carefully solder leads to your battery. Avoid excess heat when soldering Li-ion batteries and be sure not to short circuit the battery in the process or it can result in a serious fire. I recommend braided wire, though I only had solid core. The braided wire will make reassembly easier.

Red wire to the bump (+) side and Black wire to the flat (-) side of the battery.

Solder the leads to the circuit board - remember where the red (+) wire goes.

Flux will help attach the wire to the battery terminals.

I wrapped the battery in electrical tape to ensure there were no shorts during the reassembly process and to reinforce the solder joints which should not be relied on for strength.

Step 5: Reattach Circuit Board to Earbud Holder and Test

Remember where the 1 screw went and put that one in first. Then screw in the other 3.

With the circuit board attached, you can now test if the earbuds will charge by placing them on the holder. The small magnets will hold them in place and in contact with the 3 charging pins. Each earbud should slowly pulse as it is charging and some of the 3 white LEDs on the holder should illuminate.

Next, test that the case will charge from the USB micro connection. You should see one of the LEDs blinking. The new battery should have some charge already on it, so you should see 1 or 2 solid white LEDs with the last one blinking as it charges.

Finally test that the USB out port will charge another device.

Step 6: Reassemble

Carefully begin putting the earbud holder into case with the front tab into the slot in the case. The back of the holder should still be up.

Put the metal pin that goes through the hinge of the lid with the lid attached under the back of the earbud holder and carefully push it together. Be sure not to pinch any wires in the process.

Make sure the USB ports line up with the holes in the case and it snaps together.