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Medically Reviewed
Published: 11 November 2022

How to charge an electric toothbrush

Author: Jon Love (Leave a comment)
Medical reviewer: Dr Gemma Wheeler, BDS
How to charge an electric toothbrush 1

An electric toothbrush needs a power source to be able to work.  That power source is a battery or batteries in some cases.

Electric toothbrushes come in two forms: those with removable batteries (designed to be removed) and those with fixed internal batteries (not designed to be removed under normal circumstances).

In this article I will explain how to charge an electric toothbrush, how it works and how to know when your brush is charged.

Does your brush have removable batteries?

The first thing to determine is if your brush has a fixed internal or removable battery.

Most electric toothbrushes have batteries fixed inside, which can be removed with tools, but are not designed to be done at home.

Cheaper or more basic brushes have removable batteries.  Quite often these are removed or replaced via the bottom of the brush handle.  It will normally be quite obvious or not whether you can remove the battery.

There will be a removable cap that gives access to the battery compartment.

Toothbrush with removable AAA battery

Most brushes that do not have removable batteries will have a recess on the bottom of it that looks similar to that in the image below.

How to charge an electric toothbrush 2

If there is no obvious way to access the battery then it is likely the brush has a built in battery.

If the brush came with batteries that is a sign that it has removable batteries. If the brush came with a charging stand then this is a sign that the brush has a fixed internal battery.

I will now guide you through the charging process and how to know if your brush is charged.

I have split this article into two parts.  The first part is for those what have brushes with built in batteries, whilst the second part is for those who have brushes with removable batteries.

How to charge a toothbrush with fixed (non removable) batteries

This article is designed to explain the charging process for the majority of electric toothbrushes.  There are always one of two that fall outside of what is the normal process.

This is a guide only and it is always advised where possible to consult your instruction manual or the direction provided by the manufacturer of the brush.

In most cases, an electric toothbrush is charged by sitting the brush handle onto a charging stand.

The charging stand will normally come provided with the brush.  It will be a round or square shaped plate in most cases with a prong (protuberance) that sits upright in the centre.

On the base of the electric toothbrush will be a recess into which that prong fits when the brush is sat on the stand.

Typically the brush will stand in an upright position when on the stand to receive charge.

Most charging stands have a cable wired into them that leads to a plug that connects to the power outlet in the bathroom.  It is normally a 2 pin plug.  

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Many question how this charging works without physically connecting a cable to the brush.  It uses a technology called inductive charging. The short explanation is that the charger uses a coiled wire inside the charging stand and a coiled wire inside the brush handle. An electromagnetic field an electrical current is passed between the coils, in turn passing the charge from the stand to the battery inside the brush handle.

So when the charging stand is connected to mains power a current is transferred from the socket, through the stand into the toothbrush and over time this recharges the battery inside the brush.

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As mentioned there are a few exceptions, such as the Philips Sonicare DiamondClean.  It appears to charge in a glass.  It works using the same technology, just implemented slightly differently.  

The Sonicare DiamondClean and the Oral-B Genius 9000 (amongst others) both can be charged in a travel case rather than a stand.  The principle of how they charge is the same, it is just implemented slightly differently.

How to tell when the battery is charged

How you know whether your electric toothbrushes battery is fully charged or not will depend on the brand and model that you have.

Whilst between all of these there will be subtle differences in how you can tell whether they are charged or not, there are some general rules you can consider to help decide.

For the most accurate information for your toothbrush refer to the manufacturer's documentation.

Whether you have an Oral-B, Sonicare or Colgate toothbrush, one way to ensure your brush is fully charged is to leave it on charge for a long period of time.  The vast majority will charge fully within 8-16 hours, but some can take up to 24 hours.

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Irrespective of brand if you left it on charge for 24 hours, it would be fully charged by the end of it.

Some brushes will have a battery status icon on the front of the brush handle.  Normally if this is a solid green colour or no longer lit then the battery is fully charged.  If it is a flashing green, it is quite often charging.  Red or yellow colours usually depict less charge or almost no charge remaining.

Some brushes will have a battery icon on the front of the brush handle that may well be split into 3 or 4 bars.  If all 4 bars are lit, this is often a sign it is fully charged.

In most instances, manufacturers do suggest it is safe to leave your brush on the charging stand at all times.  If you take this approach it is unlikely you will ever be in a position where you are out of power.

As a guide (not an extensive list), Oral-B suggest the charging times for their models are as follows:

  • Vitality - 16 hours
  • Pro 500 - 16 hours
  • Pro 700 - 16 hours
  • Pro 800 - 16 hours
  • Pro 2 2000 - 15 hours
  • Pro 3000 - 15 hours
  • Smart 4 4000 - 15 hours
  • Smart 5 5000 - 15 hours
  • Smart 7 7000 - 15 hours
  • Genius 8000 - 12 hours
  • Genius 9000 - 12 hours
  • Genius AI - 12 hours
  • iO Series - 3 hours
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Sonicare suggest as a general rule that the charging times for all their models are up to 24 hours.  Longer than Oral-B, this is typically because their batteries last longer, but they do also suggest it is fine to leave it on the charger.

Some models will give indicators via the charging lights and battery status icons as explained earlier.

A good tip to ensure long term reliability and performance from your brush is to discharge the brush completely every 6 months and then recharge it fully.  Such activity helps ensure a long battery life. It is also worth noting that if you need to use the brush and it has not finished charging this is fine.  Use the brush and replace it on the charging stand.

Brushes that have run out of power completely may need 30 minutes or so on the charger before they can be used for one clean or before any charging lights may appear.

Can I leave the toothbrush on the charging stand?

Many people ask whether they can leave their electric toothbrush on the charging stand as they fear that leaving it on the stand for prolonged periods of time can be damaging to the battery or potentially be a safety hazard.

You should always consult the manual of your electric toothbrush to check what the guidelines and operational instructions are from your toothbrush manufacturer as it can vary.

However, as a general rule it is normally perfectly fine to leave a toothbrush on the charging stand and always on charge.

The charging stand often serves 2 purposes.  The first, to give a place for the electric toothbrush to sit securely when not in use, and secondly a means to be recharged when the battery power is low.

The power cable of the charging stand does not have to always be connected to power.  It is perfectly safe to disconnect the power and leave the brush fitted to the charging stand.  Doing so will keep the toothbrush upright and reduce any potential risk and damage to the toothbrush.

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Leaving the power cable connected is generally fine also, but it is not necessarily required.

If you keep the power connected to the charging stand, the toothbrush will be continually topped up and ready to go.

Most electric toothbrushes have electronic circuits in them that stop the brush from over-charging.  This means, once the battery is full, the brush will automatically stop charging.  Only when the power is less than full will the brush begin accepting a charge again.

It is less common today, but in the past, leaving the brush on the stand, whilst connected to power would wear the battery out quicker, causing what was known as a 'memory effect'.

Newer toothbrushes are less prone to this, particularly those with Lithium-Ion batteries.

There is differing opinion about how to keep the battery in optimum condition.  The reality is, that for most it is not worth worrying about too much.  The majority of users will just leave their brush on the charging stand connected to mains power.

If you do want to really try and gain the absolute maximum from the battery, it is best to charge it fully and then discharge it almost entirely (not completely), down to say approximately 20% then recharge it.

Taking this approach ensures you get fuller charging cycles, rather than letting the battery discharge to 75% and then keep topping it up.

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How to charge a brush with removable batteries

When a brush has removable batteries, you are not charging the brush.  This is a term that applies only to those with batteries built into the brush handle.

There is no way to recharge the batteries whilst inside the brush.

In this instance you need to dispose of the batteries that came out of the brush and replace them with equivalent new batteries, typically they are AA or AAA batteries.

You can buy rechargeable AA or AAA batteries.  These rechargeable batteries can normally be used in a brush that accepts removable batteries.  These rechargeable batteries need to be charged in a special plug/piece of equipment that you would have received (in most cases) with the rechargeable batteries.

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If using removable rechargeable batteries, do not throw them away, simply put them in the charger when the power has run out and leave to charge until they are full (follow instructions from manufacturer of batteries).

Once charged, place back into the toothbrush.

How to tell when the batteries are charged

Quite often the charging module for the batteries will give an indication when they are charged or not via an LED or status symbol on the charging unit.

There are a vast number of different types of rechargeable battery units, so this may not apply in your particular instance, so where possible refer to the manufacturer's instruction manual.

More often than not a few hours on charge will replenish the battery.

Author: Jon Love
Medical reviewer: Dr Gemma Wheeler, BDS

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