This guide will take you step by step through how to dismantle the Braun Oral-B Vitality electric toothbrush and replace the battery. The tutorial is based on the Type 3709 Vitality model. Your brush’s type number is marked on the bottom of the handle.
The basic method is:
- Dismantle handle
- Desolder old battery
- Remove PCB
- Replace battery
- Replace PCB
- Solder in new battery
- Reassemble handle
This is documented in detail below along with lots of pictures. Click on any picture to enlarge it.
We have also created a short video from this guide to Braun Oral-B Vitality battery replacement here, which you can watch below.
Any damage to yourself, your toothbrush or anything else is entirely your responsibility. This guide is for professional, educational purposes only and is offered without guarantee or liability.
Tools / Parts / Equipment
- Braun Oral-B Vitality toothbrush (Type 3709)
- Original recharging base
- Soldering iron: Electronics grade (about 18-25 watts)
- Solder: Lead-free silver solder is great for this
- Solder sucker (also known as a desoldering pump) and/or desoldering braid/wick
- Craft knife e.g. scalpel, snap-off, retractable or Stanley type
- Small flat-bladed screwdriver: 2 to 4mm wide
- Replacement battery: 49mm by 14mm 1.2V NiMH with tags available from ToothbrushBattery.com
To start off remove any heads from the brush and insert the top of the handle into the middle hole in the back of the recharging base. If your charger does not have this hole, you can use an old toothbrush head held with grips to open the brush.
Carefully twist the handle anti-clockwise. It should start to open up but might be stiff so keep twisting it back and forth. It will only twist about an eighth of a turn and then you can slide out the innards. This is the most difficult step and there is the risk of shearing off a piece of your brush or splitting the charging base so be patient and work it loose little by little.
Now that the handle is open you can wiggle the innards out. The spring might fall out so don’t lose it!
Remove the spring from inside the copper coil at the base of the handle and put it somewhere safe.
Below is where the negative battery terminal is soldered to the circuit board (arrowed):
Using the soldering iron and the solder sucker, desolder the battery’s metal tag from the circuit board and bend it away from the board with the knife. We’re desoldering this first so that we don’t accidentally short out anything when working at the other end.
Moving up to the other end of the circuit board, identify the two motor terminals (arrowed, left) and the positive battery terminal (arrowed, right).
Desolder these three terminals and bend the tabs upright using the knife. You need to remove all the solder from these so that the metal tabs can move back and forth in their holes allowing the circuit board to be removed later. Desoldering braid is ideal for this.
Gently pry the circuit board up at the power button end so that it pops off its plastic peg and starts to come up off the three terminals you just desoldered.
Heading back down to the negative terminal end, identify the two black plastic tabs that hold the coil to the white chassis of the handle. There is one on each side. See arrow:
Use the screwdriver to gently pry the clips and then slide the coil and circuit board assembly out.
The battery might or might not come out depending on how well the clip (arrowed) at the positive end is holding it in.
Remove the battery from its clip and check its measurements. This single-speed Vitality toothbrush has a 49mm long by 14mm diameter battery with welded on solder tags. Compare it to the same size replacement shown, available from our online toothbrush battery shop here at ToothbrushBattery.com
The solder tags on the new battery will need trimming with scissors to a similar length as the old battery. Optionally you can shape the positive tag of the new battery so that it fits in the clip like the old one, though you can skip this if you like and keep it straight. Negative terminals (top) and positive terminals (bottom):
Test fit the new battery in the chassis of the handle and check that the clip engages with the tag on the positive terminal.
Once you’re happy enough with the clip, trim the tip of the positive terminal to roughly match the old battery. It needs to fit through the slot in the circuit board and have enough metal poking through to bend over and solder to the board.
Test fit the new battery to the toothbrush circuit board.
Once you’re happy with the shape of the tag, clip the battery back into the handle and carefully replace the circuit board and coil assembly so that the motor and battery solder tags poke through the holes in the circuit board.
Bend the positive battery tag over and solder it onto the circuit board, and also re-solder the motor terminals.
Move down to the bottom end of the circuit board and solder the negative tag of the new battery to the circuit board.
Replace the spring inside the coil then you’re ready for reassembly!
And that’s it! You will need to put the toothbrush on charge for 24 hours before use so don’t be surprised if it seems dead after reassembly. Please recycle your old battery either at a local civic facility or a supermarket.
Please leave any questions or comments on our dedicated Vitality blog post here.