Braun Oral-B Sonic Complete Model Toothbrush Battery Repair and Replacement Instruction
Battery Selection Guide: The original battery is composed with two NiCd cells in tandem. You have a much better choice by going with NiMH, which is compatible with NiCd in charging and discharging performance and has much larger capacity. The benefit of a larger capacity is that your handle holds more energy and recharges less often, resulting in a much longer battery life and handle life. Better yet, NiMH doesn't have the "memory" problem associated with the NiCd. Both are available in our Battery Store, check listings there for exact battery specifications. We are different from all the other toothbrush battery sellers; we test all our batteries for correct charging and discharging before shipping. It is VERY UNLIKELY a new battery you receive from us is defective, unless it is physically damaged in shipping. If your handle doesn't work after the battery replacement, PLEASE check the charging to make sure the battery is charged correctly before use. Some models are known to have the battery indicator showing low prematurely. Instructions on solving this issue is provided free with the battery.
A commonly asked question from buyers was "Oral-B uses plastic wrapper to enclose two cells and make them in tandem. Why don't you make the same way?". Here is the answer: the heat-shrink plastic not only is unnecessary but also does more harm to the battery. To shrink the plastic wrapper, it requires a temperature of 257F (125C) and higher, which is detrimental to battery life. Secondly, the plastic impedes heat dissipation when battery charges and discharges, further reducing battery's life. A rule of thumb is every 40 degree C rise in temperature reduces battery's capacity and life in half. See this link for details. So then why does Oral-B allow this? Well, this is part of a planned obsolescence so the customer has to buy the expensive toothbrush handles regularly. However, we do care for our customers and this is the best solution to extend battery life. In the next step, you will see even the soldering between two cells is unnecessary.
Step 7: Arrange two new cells in tandem: make sure they are held together with good electrical contact via the tabs in between. Soldering between cells is not necessary as the spring, when installed, will push cells together, naturally securing the in-between contact. The battery has marking of + on the cylindrical wall. Alternatively, the positive side of the battery is indicated by the depressed ring around that end of the battery. Trim the positive tab to fit into the positive soldering hole on the circuit board. Fit the battery into the battery holder and solder the positive tab to the circuit board.
Step 8 (Optional): Solder negative battery tab to the original negative tab still attached to the circuit board. Remember to prepare the contact areas on both pieces before soldering and solder two pieces together quickly. Note that heat from solder gun, if handled inappropriately, could damage the battery. This step can be skipped if the original negative tab is pressed against the battery negative by the spring in the next step. Again, WATCH OUT for the four tiny wires so not to break them by any chance. Align the toothbrush and insert back into the housing.
Step 9: The last step is tricky. Align the bottom cap and spring with the housing. Use the stub on the charger to help put the bottom cap back in. Push the handle with bottom cap down fully onto the stub and then twist the handle about 45 degrees clockwise into "locked position".
This instruction is provided to you for FREE. Both battery and battery replacement service are available by contacting us by the email shown below. Some tools needed for replacing battery and coupons to buy a new handle are sometimes linked in this website from third party sponsors.
Please let us know any suggestion so we can do better in providing these instructions to you and future visitors. Please specify the step number in your email. Contact email link: etoothbrushcare@gmail.com
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