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How to tell if a Roomba is charging

Alvina Wang/BestReviews

Is your Roomba charging properly?

Roombas are a great way to stay on top of housework — but first and foremost, they need to be charged. 

Roombas have indicator light rings that tell you whether they’re charged and ready for work. You can also see exactly how much power your Roomba has left via the iRobot Home app on your smartphone.

But just because your Roomba’s indicator light is off doesn’t necessarily mean it’s not charging. A Roomba can turn the indicators off after three or four seconds on the base to save power while still charging. The dock may have its lights turned off, too.

So how do you really know if your Roomba is charging? We’ve checked out various Roombas in the BestReviews Testing Lab to help answer all your questions. You’ll find out how to check your Roomba’s charging status, what the various light indicators mean on various Roomba models, what it means when your Roomba notifies you of a charging error and what to do if your Roomba just isn’t charging at all.

Is your Roomba charging?

It’s not always easy to tell if your Roomba is charging. Here’s some information and tips on what to look for and what to do if it isn’t.

Roomba batteries

Roombas run on removable, replaceable lithium-ion batteries, the same kind of batteries found in most smartphones and laptops. A Roomba charges its batteries while it’s resting in its base. At the bottom of every Roomba is a pair of metal charging contacts that line up with the charging contacts on the base. When the Roomba’s contacts meet the contacts on the base, electricity flows into the Roomba’s battery via the base, which is plugged into a wall outlet.

Press the “Clean” button

The quickest way to check if your Roomba is charging is to press its “Clean” button while it’s on its base. This is the biggest button on the top panel of your Roomba. If your Roomba is charging correctly, its ring indicator light will shine solid or pulse gently. The color depends on which model of Roomba you have (see below for more details about what each color means).

Check the app

Another way to check if your Roomba is charging is by using the iRobot Home App. All Roombas with Wi-Fi capabilities, such as the 600 series, i series, j series and s series, can connect to the iRobot Home app for iOS or Android. When a Roomba is set up in the app, a battery indicator will show the amount of charge remaining. If it’s charging, there will be a small lightning icon next to the battery indicator.

Check the power cord

If you’ve checked and your Roomba isn’t charging, first make sure its base is plugged in and that its power cable is seated correctly.

Clean the charging contacts

The Roomba’s charging contacts can easily get covered in dust and grime. Be sure to clean the charging contacts on both the base and the bottom of your Roomba at least once a week. iRobot recommends a melamine foam sponge, such as the Mr. Clean Magic Eraser.

Check the power outlet

If everything on your Roomba seems to be OK, check if the power outlet is working. Plug your Roomba’s Home Base or Clean Base (the base you have depends on the model) into a different power outlet temporarily and place your Roomba on the charging contacts.

Remember that if you have a Roomba that supports smart mapping, and you change the location of its home base permanently, you may need to remap your home so your Roomba can get its bearings again.

Roomba light indicators

Different families of Roomba models have different indicator lights, colors and behaviors. The following is a list of all the different light colors you may encounter for Roombas from the 400/Discovery series onward.

For 400/Discovery, 500, 600 and e series

  • Solid green: fully charged
  • Solid amber: partially charged or charging
  • Pulsing amber: charging
  • Red: partially drained
  • Flashing red: too drained to continue or start a job

For 700 and 800 series

  • Solid green: fully charged
  • Solid red: fully drained, needs recharging
  • Flashing red: charge too low to start cleaning
  • Pulsing amber: charging
  • Quick pulsing amber: in 16-hour refresh charge mode

For 900 series

  • Battery indicator icon flashing: charging
  • Battery indicator icon solid: charged

For i series, j series and s series

These Roombas use a ring around their “Clean” button up near the front and use a different color and behavior scheme.

  • Solid white: battery is charged
  • Pulsing white: battery is charging
  • Pulsing red: battery is charging but charge is too low for the robot to start a job
  • Spinning white: updating firmware or booting up

Roomba charging errors and solutions

Your Roomba may inform you it’s experiencing some kind of charging error with a number. Here’s the list of errors and their solutions from iRobot:

Charging Error 1: Battery not detected.

  • Solution: Install a new battery.

Charging Error 2: Possible wrong battery type or liquid damage.

  • Solution: Check for damage and make sure you’re using a Roomba lithium-ion battery.

Charging Error 3: Possible liquid damage.

  • Solution: Check for damage and try again.

Charging Error 4 or 5: Low-current fault detected.

  • Solution: Clean the charging contacts.

Charging Error 6 or 7: Battery too warm or too cold to charge.

  • Solution: Bring Roomba to room temperature and try charging again.

Charging Error 8: Can’t communicate with battery.

  • Solution: Replace with genuine Roomba battery.

Charging Error 9 or 11: Battery failure.

  • Solution: Replace with genuine Roomba battery.

Charging Error 17: Not a genuine iRobot Roomba battery.

  • Solution: Use a genuine Roomba battery.

Charging Error 19: Charging timeout.

  • Solution: Take the battery out and put it back in, and clean the charging contacts.

Charging Error 20: Something may be wrong with the battery.

  • Solution: Remove the battery for 15 minutes, then reinstall. If the error persists, replace the battery.

Charging Error 21: Docked but unable to charge.

  • Solution: Try cleaning the charging contacts. Clean both the contacts on the Roomba and on the base.


How long should it take a Roomba to charge?

A. Roombas take two to three hours to fully charge their batteries. Roombas that are getting low in battery power let you know their status while they’re working by showing a red or amber light, depending on their model.

Many Roomba models automatically return to the base to charge if they run low on power during a cleaning job. Even better, some models with smart-mapping capabilities (the s series, i series and Braava m series) support the Recharge and Resume feature, which means the Roomba can return to the base to get just enough power to finish its task and pick up right where it left off. Once the job is completed, the Roomba then returns to the base to fully recharge.

If a Roomba’s battery is so drained it can’t make it back to its base, it stops the current job and alerts you to recharge it.

Should I leave my Roomba on the charger all the time?

A. Yes, iRobot recommends you keep your Roomba on its base to charge whenever it’s not in use. You may be familiar with the advice not to keep a smartphone or similar device charging all the time, but iRobot says Roombas use a tiny amount of power even while they’re on their base to keep their batteries healthy. Frequent use also helps keep the Roomba’s battery working well.

iRobot does recommend putting your Roomba into “shipping mode” (which is the mode it first arrives in) if you won’t use it for several weeks.

Is it normal for a Roomba to get warm when it’s charging?

A. You should expect your Roomba to get a little warm while it’s charging, but it shouldn’t get hot. If your Roomba feels hot to the touch, contact iRobot customer support. You might have a damaged or defective battery or unit.

Roomba batteries charge best in comfortable temperatures, and excessive heat can interrupt charging or cause damage. A too-hot Roomba will report a Charging Error 6, which means the battery is either too warm or cold, and you should take it where it can return to room temperature before trying to charge it again. A good rule of thumb is if a room is uncomfortably hot for you, it’s probably too hot to optimally charge a Roomba.

Keep your Roomba charged

Keeping your Roomba charged and healthy is easy once you know the right steps. Let your Roomba stay on its base until you need it. Don’t worry if the Roomba’s indicator lights aren’t on. Check your Roomba’s charge status by pressing its “Clean” button or going to the iRobot Home app. And remember to run your Roomba frequently to keep its battery at its best.

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Jmar Gambol writes for BestReviews. BestReviews has helped millions of consumers simplify their purchasing decisions, saving them time and money.

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