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WaterPik WP-450 Battery Replacement

Introduction

This is a guide on how to replace the battery of a WP-450 WaterPik electronic water flosser.

If your WP-450 WaterPik electronic water flosser has lost its ability to hold a charge or cannot power on entirely, it most likely has a faulty or dead battery.

The WP-450 WaterPik is powered by a rechargeable NiMH battery. Over time, this battery will gradually lose capacity and discharge at a faster rate, meaning it will die much quicker. If you notice that your water flosser is losing charge much quicker or is entirely non-functioning while unplugged, you should replace your battery.

Make sure to power down your device before you begin.

Please note that this repair guide will require knowledge of soldering in step 9. The battery of the WP-450 WaterPik water flosser provides power to the device allowing water to shoot out the nozzle.

What you need

  1. WaterPik WP-450 Battery Replacement, Battery: step 1, image 1 of 3 WaterPik WP-450 Battery Replacement, Battery: step 1, image 2 of 3 WaterPik WP-450 Battery Replacement, Battery: step 1, image 3 of 3

    • Press and hold down the grey button to release the water nozzle.

    • Gently pull the water nozzle up to remove.

    Edit

  2. WaterPik WP-450 Battery Replacement: step 2, image 1 of 3 WaterPik WP-450 Battery Replacement: step 2, image 2 of 3 WaterPik WP-450 Battery Replacement: step 2, image 3 of 3

    • Push down on the release tab for the water tank and gently pull to remove from the main body.

    Edit

  3. WaterPik WP-450 Battery Replacement: step 3, image 1 of 2 WaterPik WP-450 Battery Replacement: step 3, image 2 of 2

    • Insert a spudger between the nozzle cap and the main body of the flosser.

    • Leverage the spudger to carefully separate the nozzle cap from the body.

    • Use a napkin, towel, or tissue to prevent scratches in the plastic of the main body.

    Edit

  5. WaterPik WP-450 Battery Replacement: step 4, image 1 of 2 WaterPik WP-450 Battery Replacement: step 4, image 2 of 2

    • Use a Phillips #2 screwdriver to remove the four screws that hold the upper cover in place.

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  6. WaterPik WP-450 Battery Replacement: step 5, image 1 of 3 WaterPik WP-450 Battery Replacement: step 5, image 2 of 3 WaterPik WP-450 Battery Replacement: step 5, image 3 of 3

    • Press the charge port on the bottom of the water flosser to push the upper part out.

    • As you hold the charge port, loosen and take off the cover of the water flosser.

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  7. WaterPik WP-450 Battery Replacement: step 6, image 1 of 1

    • Remove the two screws on top of the exposed mechanism of the water flosser using a Phillips #2 screwdriver.

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  8. WaterPik WP-450 Battery Replacement: step 7, image 1 of 3 WaterPik WP-450 Battery Replacement: step 7, image 2 of 3 WaterPik WP-450 Battery Replacement: step 7, image 3 of 3

    • Rotate the main body outward, using the top as the pivot point.

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  9. WaterPik WP-450 Battery Replacement: step 8, image 1 of 3 WaterPik WP-450 Battery Replacement: step 8, image 2 of 3 WaterPik WP-450 Battery Replacement: step 8, image 3 of 3

    • Remove the screws using a Phillips #2 screwdriver.

    • Remove the white plastic cover to get access to the battery.

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  10. WaterPik WP-450 Battery Replacement: step 9, image 1 of 1

    • Use a soldering iron to melt the solder at the positive and negative terminals of the battery, and remove the battery.

    • Soldering MUST be performed in a well-ventilated area and risk of burns.

    • A soldering guide can be found here: FixHub Soldering Iron User Guide

    Edit
Conclusion

To reassemble your device, follow these instructions in reverse order.

Author

with 3 other contributors

Connor George

Member since: 10/09/25

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Team

UC Davis, Team 2-5, Morris Fall 2025 Member of UC Davis, Team 2-5, Morris Fall 2025

UCD-MORRIS-F25S2G5

3 Members

1 Guide authored

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