Electric Toothbrush Battery Replacement (Oral B / Braun Vitality)

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Introduction: Electric Toothbrush Battery Replacement (Oral B / Braun Vitality)

About: An engineer who likes to tinker with electronics and make stuff!

Hi there - here is a repair and an upgrade all in one!

I've been using this electric toothbrush for a few years now. Gradually the battery has lost it's ability to hold charge to the point where it needs to be plugged in (or rather placed on the charging holder) every few days. I though I'd try changing the battery (actually 1 cell as I discovered) and see if I couldn't get a performance enhancement at the same time.

As with many of my Instrucables you can either read the steps here or sit back, relax and watch the video embedded here or browse my YouTube channel linked here.

https://www.youtube.com/user/MrSjowett

Step 1: Disassemble the Toothbrush

1) Remove the brush head

2) Using a small adjustable spanner place this around the flat of the white plastic part of the toothbrush as shown and twist the spanner anticlockwise

3) After twisting about 30degrees the white plastic should disengage from the main body of the toothbrush

Step 2: Slide Out the Inner Mechanism

Once released the inner mechanism should slide out easily.

Take care not to lose the spring at the bottom of the mechanism (inside the copper coil).

Set aside the main body and the spring - we won't need these until we come to reassemble the toothbrush.

Step 3: Inspect the Inner Mechanism

On one side of the mechanism is the PCB (Printed Circuit Board), The PCB controls the charging of the cell (battery) and also drives the motor. The PCB also has the momentary push button up near the top. Turning the mechanism over we can just see the cell (yellow in colour).

Step 4: Preparation for the Removal of the PCB

De-solder the 4 tabs that hold the PCB and cell in position. 2 of the tabs go to the motor and the other 2 go to the positive and negative of the cell. The negative tab on the cell needs to be bent up to enable the PCB to be removed. Once this is done the PCB can be simply lifted away from the rest of the mechanism.

Step 5: Slide the Cell Out of the Body

After the PCB is removed the cell can be simply slid out of body of the mechanism. I'm not too sure on the capacity of the original cell but it has the number 600 on the outside so I'm going to assume that refers to 600mAh. I'm replacing this old NiCd cell with an Eneloop NiMh cell with a 2000mAh capacity so I'm hoping for a (at least) x3 increase in time between charges (in comparison to the original cell).

Step 6: Spot Weld or Solder Tabs Onto the New Cell

I have a battery spot welder which I used to attach the 2 battery tabs but the tabs could be attached by soldering - just go easy with the amount of heat you apply to the terminals of the cell to ensure you don't damage the cell itself!

Step 7: Slide the New Cell Back Into the Holder

Now it's time to start the re-assembly!

Firstly, the new cell has to be slid back into the body of the mechanism. Carefully align the positive tab of the cell with the slot so that it will line up with the PCB

Step 8: Re-attach the PCB

The 4 joints previously de-soldered need to be re-soldered!

Remember the negative tab needs to be bent 90Deg to enable it to be soldered to the PCB

Step 9: Reassemble and Finish

With the spring at the base inserted into the coil, the assembly can be slid back into the body. Ensure the parts are aligned by making sure the switch on the PCB is lined up with the button molding on the outside of the case. The 2 parts are then pressed together firmly and they should snap together in 1 shot - so to speak.

Initially I found that the toothbrush wouldn't work but I found that it re-energised the internal chip when I placed it back on the charging cradle momentarily.

Now your finished!


PS in the 3 weeks since completing this I've only recharged the toothbrush once - and even then it hadn't fully discharged like it used to do!

3 People Made This Project!

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7 Discussions

0
elias.alberto
elias.alberto

Question 6 months ago

On today's episode of Pimp My Toothbrush, I wanted to put a lithium ion cell instead of the old Nickel cell. I've checked the open circuit voltage of the charging board, and it outputs 5 volts, which should be enough to fully charge a protected lithium ion battery. However, I'm not sure if the voltage from the battery is connected straight to the vibrating motor, in which case it would probably be deadly to power it with 4.2v instead of 1.2v... any thoughts on this?

0
limitingfactor
limitingfactor

Answer 4 weeks ago

I wouldn't do this - decent chance it will fry the electronics.

0
mpikas
mpikas

Answer 6 months ago

Have you tried it yet?

0
limitingfactor
limitingfactor

Tip 4 weeks ago

Desoldering braid is good for cleaning up the connections. Also, get yourself a flat top AA cell with tags already attached - fits better than a standard AA.

0
mailpentruloggm
mailpentruloggm

2 months ago

Now they seem to have a protection. When I tried to remove the battery something happened and it won't start anymore...

0
Mark Boulton
Mark Boulton

1 year ago on Step 9

Did this and after re-energizing it, it worked but I then put it on charge overnight and in the morning, nothing. Cant get it to work again !
pulled it to bits again and again and checked the voltage and powered the motor outside and all look fine but when i assemble it, nothing !