Symptoms
- Brush starts strong then slows or stops within a minute
- Battery indicator drops rapidly after a full charge
- Runtime has gotten noticeably shorter over months
Likely causes
- CommonDegraded rechargeable batteryLike any rechargeable battery, capacity fades with age and repeated charge cycles.
- PossibleIncomplete chargingRemoving the brush from the charger too soon can leave it under-charged.
- PossibleMotor or brush head resistanceA worn brush head or debris around the motor can make it work harder and drain faster.
- Less commonCorroded charging contactsCorrosion can prevent a full charge even when the light indicates otherwise.
What to do
- Leave the brush charging for a full uninterrupted cycle, usually 12–24 hours.
- Replace the brush head if it's older than 3 months, since resistance can strain the motor.
- Clean around the base of the brush head where it meets the handle.
- Wipe the charging contacts on both the brush and base.
- Track how long a full charge lasts to see if runtime is truly shrinking.
- Compare against the manufacturer's expected runtime for your model.
- Replace the unit if runtime is far below spec despite a full charge and clean contacts.
Tools and parts
- Soft cloth
Replacement brush headSearch: “electric toothbrush replacement heads”
When to call a pro
A steadily worsening runtime despite a full charge means the battery is worn out; since these aren't user-replaceable, plan to replace the toothbrush.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.