Roomba Battery Not Charging: Fix It Before You Replace It

The way charging works is like this: the robot moves onto the dock, the two metal pads under the robot come into contact with the two pads on the dock, and as a result current goes into the battery pack. This process has three weak points—the pads, the connector on the pack, and the electronics which control the charging. A dead battery is only one of those weak points.

When a robot stops charging, I don't begin by checking the battery; instead I look at the free repair option since in most cases that free repair is the solution. If the battery really has failed, the final step will clearly tell you so and it will also tell you which battery to buy.

What your robot is telling you

The seven fixes, in order

Fix 1: Clean the charging contacts

The robot moves across two metal pads on the bottom of it and the dock has the corresponding pairs. Even a thin layer of dust and lint on either of the pairs is sufficient to cause the charging to stop.

Take the dock out of the setup. Use a dry cloth to clean the pads on the robot and on the dock; if the pads are greasy, use a cloth that has been slightly dampened with 91% isopropyl alcohol. Do not use anything wetter than that.

The solution is the one which most frequently works; I have seen a robot remain on its dock all night and still be dead in the morning simply due to a layer of dust on the contacts.

Fix 2: Reseat the battery

Put the robot down on a towel, undo the screws at the bottom (most models have four or five), lift off the cover and remove the pack. Examine the connector, blow any dust out of it and then push the pack back in until it clicks into place. Put the screws back and place the robot on the dock.

More robots have been repaired by simply reseating them than by any of the other methods listed. A pack may appear to be seated but can still be half a millimeter off, and that amount of gap is all that a connector needs to lose contact.

Fix 3: Test the dock and the outlet

Start by checking the cheap components. Connect the dock to a different power outlet. If the dock is fitted with a light, make sure that it switches on. Then, if your model has a side charge port, try charging the robot directly using that port since most i and j series robots do have one. If the robot charges when using the port but not from the dock, then you have located the issue and the cost will be less than that of a battery.

Fix 4: Reset the robot

Robots can become confused and this problem can be solved by carrying out a reset. With the i and j series, press and hold the Clean button for around twenty seconds until the ring turns white and then let go. For the older 500 to 900 series, hold down both the Spot and Dock buttons for approximately ten seconds until the robot emits a beeping sound.

The exact combination of buttons may differ according to the model; if your robot doesn't respond, consult the manual that corresponds to your particular robot.

Fix 5: Give it a long refresh charge

If the pack has reached a deep discharge, the dock by itself won't be able to recharge it; you should plug the charger directly into the robot where there is a port and leave it for up to 72 hours, even after the light turns green, since this slow recharging can rebalance the cells.

It will cost you nothing except patience; if the pack is empty after three days then it's finished.

Fix 6: Check the voltage

Put the multimeter on the DC volts setting and connect the probes to the terminals of the pack. A good pack will show about 14 volts. If the reading is 11 volts or less, then the pack is unable to hold a useable charge and no amount of cleaning or resetting will be able to repair it.

Ten seconds is more informative than an hour spent guessing, and I don't buy a new battery until I've measured the one I currently have.

Fix 7: Accept the pack is dead, and buy the right one

You've already been given Fix 6. If the voltage is low or the robot still won't charge after having carried out all six fixes, then the battery has reached the end of its life. That is entirely normal since these batteries are consumable items and a good usage period is indeed two to three years.

Don't buy the first battery you find. Read the part number off the old pack's label (it starts with ABL- or 4INR) and match that number to the listing. Our Roomba battery collection organizes every pack by robot series, and the compatibility guide walks you through the ABL-D1 vs ABL-D2 plug trap. Wrong plug, wrong robot, and the new pack physically won't fit.

Two signs the battery is dying even though it charges

The robot may still have the battery problem even when it is charging. Keep an eye out for these two indications. The first is that the robot operates for less than 30 minutes on a full charge; on the majority of models a healthy battery should last between 60 and 90 minutes. The second is that it returns to the dock during the job, before the cleaning of the floor has been completed.

If you see either one, skip the fixes and go straight to choosing a pack. How long a pack should last is its own topic, and I covered the numbers there. And if the plug situation confuses you, the ABL-D1 vs ABL-D2 vs ABL-F piece sorts the labels out in plain English.

Every pack we ship is tested before it goes in the box, and covered for a full year.