Hi.
If the red light is solid, that means that the Roomba is near to full discharge. If the light is flashing red, then the Roomba is completely out of charge.
If the Roomba is fully charged, then there may be a fault.
Here full list of light codes:
Pulsing Amber - Charging
Green - Fully Charged
Amber - Partially Discharged
Red - Almost Fully Discharged
Flashing Red - Fully Discharged"
Here manualSee also
Roomba DISCOVERY MODELS' DIAGNOSTIC TESTS
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