iRobot Roomba Red (4100) fails to start

iRobot Roomba Red (Model 4100) fails to start. I plug in the Roomba to charge the battery until the power light is green. When charging is complete, the Roomba exhibits the behavior shown in the video. Eventually, the Roomba indicates that the battery needs charging, so I plug it in again.

You may notice that the vacuum fan turns on, but the Roomba halts as soon as the wheel drive motors are told to turn.

I’ve done some troubleshooting and believe that some electronic components within the Roomba charging circuit are damaged. I can charge the battery outside of the Roomba as shown on this website and the Roomba actually moves for a bit when I put the battery back in.

If this is happening to your Roomba, you probably either have a bad battery or a bad charging circuit inside your Roomba.

Update: I opened the Roomba and didn’t see any obvious signs of circuit damage on the main board, but that doesn’t necessarily mean the components (MOSFETs U2, U4) are in good shape. Hmm….

2 Replies to “iRobot Roomba Red (4100) fails to start”

  1. crackoplcracko


    this is due to battery is down.Buy new one on ebay and remember one thing. ALWAYS KEEP IT CHARGING – when you finish cleaning – plug it in immediately and keep it charging (PLUGGED IN) until you need it again. So – cleaning and back to charging EVERY TIME>
    In case of wheel problems- go here ->

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