Electric Toothbrush Battery Replacement

Guide to replace your Oral-B Vitality 100 battery and give your toothbrush a second life!

Introduction

In March 2022, I purchased my Oral-B Vitality 100 CrossAction electric toothbrush. After two years of daily use, the battery began requiring frequent recharging, often several times a week. Instead of spending arout 20€ on a new toothbrush, I chose to replace the battery myself with a brand new Eneloop NiMh cell, which would cost you roughly 3€ a piece. This way we’re able to save money, and most importantly, contribute to less electronic waste.

What You’ll Need

  • 🔋 Replacement Battery (e.g., Eneloop NiMh cell, AA size)
  • 🔧 Combination Pliers
  • 🧰 Soldering Equipment (Soldering Iron, Solder and Desoldering Pump)
  • ✨ Clean Workspace

Step-by-Step Guide

Step 1: Disassemble the Toothbrush

Before you begin, make sure you have all the necessary equipment listed above. Take a moment to organize your workspace.

  1. Firmly grip the metal shaft with the pliers. Wrapping a towel around the shaft helps protect it from scratches and provides a better grip
  2. Gently twist it anticlockwise by about 30 degrees. You should feel the white plastic section unlock and separate from the main body of the toothbrush.

Step 2: Slide Out the Inner Mechanism

Once the plastic section is unlocked, the inner mechanism should slide out smoothly from the main body.

Notice the small spring located at the bottom of the mechanism, inside the copper coil. This spring is essential for proper operation, so be careful not to lose it during disassembly.

Step 3: Removal of the PCB

  1. Carefully desolder the four metal tabs that secure both the PCB and the battery cell in place. Two of these tabs connect to the motor, while the other two connect to the positive and negative terminals of the battery cell.
    • The ideal temperature should be between 175°C and 200°C (about 350°F to 400°F).
  2. Gently bend the negative tab upwards by about 45 degrees. This will release the PCB, allowing you to carefully lift it away from the rest of the mechanism without applying excessive force.
  3. There are small clips near the top of the PCB, as shown in the image below. You need to gently pry these clips holding the PCB in place using a small flathead screwdriver or plastic spudger.

Once all tabs and clips are free, the PCB should come off easily together with the battery, without requiring much force.

Step 4: Solder Tabs Onto the New Cell

  1. Using the pliers, detach the metal tabs from the old battery cell. These tabs may be firmly attached, so use gentle but steady force to avoid bending or damaging them. Reusing the original tabs ensures a perfect fit in the toothbrush mechanism.
  2. Clean the tabs if necessary, then solder them onto the terminals of the new battery cell. Make sure the tabs are securely attached and positioned correctly to match the original orientation.

Step 5: Re-Attach the PCB

  1. With the tabs securely attached to the new battery, carefully position the PCB back onto the mechanism. Align the metal tabs with their original locations on the PCB and battery terminals.
  2. Re-solder the four joints that were previously desoldered: two for the motor and two for the battery terminals.

Step 6: Reassemble

Carefully slide the inner mechanism back into the main body of the toothbrush, ensuring that the spring and all components are properly aligned. If everything looks good, reattach the end cap.

Once reassembled, test the toothbrush to confirm that it powers on and operates correctly. If it does not turn on, check the battery orientation, tab connections, and solder joints for any issues.

Congratulations! You have successfully replaced the battery and extended the life of your electric toothbrush. 👏