We use two Braun Oral-B electric toothbrushes. Both use a NiMh rechargeable battery that looses its capacity over time. One of the toothbrushes even shut down completely during its use, even when it was charged more than 24h before. So I started to check what must be done to replace the battery.
I’ve found two detailed instructions for both our toothbrushes. The one is for a Braun Oral-B Professional Care 500 (Type 4729) and the other is a Braun Oral-B Professional Care Type 3754 & 3756. You can find the exact type number on the bottom of the toothbrush.
- a soldering iron
- lead free solder
- a desoldering pump - You’ll need to desolder the batteries as well as the motors
- desoldering braid - helps a lot when the desoldering pump did not get everything and connectors are still stuck
- Wirecutter - to shorten the connectors from your replacement battery
- a replacement batterie - search for the type number in combination with replacement batterie on a web shop of your choice
The complete replacement of two toothbrush batteries was done in a single evening and took me two hours. Its not that complicated and spares you unnecessary electro waste. Its also a good chance to see the insides of these little machines and how they are recharged. Pretty interesting engineering. Too bad its