How-To: Replace your electric toothbrush battery



Instructables user AaronX621 writes:

This will show you how to replace the internal battery on your Sonicare Elite 7300. After having my 2nd one die on me within 3 yrs I figured out how to rip it apart and fix it.

8 thoughts on “How-To: Replace your electric toothbrush battery

  1. It is a great idea to replace a bad rechargeable battery when possible. My cordless soldering iron is on its third set of batteries. My Braun toothbrush had a special key molded into the charging base for removing the battery. I was curious so I placed the toothbrush into the key and gave it a twist. There was a strong spring inside which forced the toothbrush apart, breaking the thin wires to the charging coil. D’oh! It was only meant to be used to recycle the battery at its end-of-life.

    1. Aha! The recycling symbol made me delay opening my Braun until it has to be opened. Thanks for the warning. Do you think it would have been possible to replace the battery if you had known about the spring? Did you end up being able to repair your toothbrush?

      1. I think I could have fixed it. One of the coil wires broke where it entered the coil. I unwound the entire coil of very thin enameled magnet wire, and then rewound it with a short piece hanging out. I had it ready to reassemble, but left it out for a few too many days and my wife threw it away! To be fair, it may have been a few too many weeks or months. Definitely less than a year. The expensive rechargeable brush came with a free second one which used disposable AA cells. I used it until the bristles wore out and then I wore out the brush head from the expensive one. Other than the built-in charging and a silly timer, I think the cheap one was as good as the expensive one. Ever since, I only buy the cheap units because they cost about the same as a replacement brush head. I put my own rechargeable AA cells into them.

  2. Once you’ve got it apart (the hard part) measure up the size of the battery so you can buy the correct size, as there are several odd sizes available! This one is a 42mm long, 17mm diameter size and you can replace it with a NiMH battery of the same dimensions. Avoid soldering direct to the battery terminals as this will internally damage the battery so buy one with metal tabs already fitted e.g. the ones at
    Once it’s soldered in remember to clean up the seal around the top of the brush before reassembling!

    Dave G.

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Becky Stern is a Content Creator at Autodesk/Instructables, and part time faculty at New York’s School of Visual Arts Products of Design grad program. Making and sharing are her two biggest passions, and she's created hundreds of free online DIY tutorials and videos, mostly about technology and its intersection with crafts. Find her @bekathwia on YouTube/Twitter/Instagram.

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