The battery life of the Roomba depends on how often you use it and how you use it. If you take good care of it, its service life is about 1-3 years, depending on the model. If you find that it doesn't run as long as before or the overall performance drops, then you need to replace the battery for it at this time.
If you find a suitable battery, it's time to replace it. First turn the vacuum over, use a flat-head screwdriver to loosen the side brush screws, and remove the side brush.
Loosen the edge brush screw
Next, unscrew the other screws on the bottom cover. After removing the bottom cover, you will see the battery.
Loosen other screws on bottom cover
Remove the old battery from the vacuum and insert the new battery into the battery hole. The battery tag holds it in place.
Put the new battery in
If you have a suitable side brush at home, you can replace it when assembling. Make sure the cover is level after placing the cover. Tighten the screws to make sure there are no remaining screws left. After installing the side brush, tighten the side brush screws.
Cover the bottom cover
Charge your Roomba and make sure it works properly. If something goes wrong, then you may need to contact the iRobot Customer Care.
The Roomba's battery lasts a long time if you keep it in good condition. You may want to pay more attention to its performance around the time, and it may send you some signals. How do you know you need to replace the battery for it? For example:
Its runtime starts to slowly get shorter.
Even when cleaning or resetting the Roomba, it performs poorly.
The battery is not charged or the power light is not on for extended charging time.
When these situations occur, there is a high probability that you need to replace the battery for it.