Why is my robot not holding a charge?

@bigbuilder a bad battery can do that. Replace the battery and re-evaluate. Since iFixit does not yet have a guide for that, use something like this video to replace the battery.

While you work on your Roomba, take lots of pictures. Once you are done with it, take those pictures and create a guide for iFixit. That will help the next person that has the same problem as you do. It's easy and fun to create these guides. https://ifixit.com/Guide/new The iFixit community will appreciate this.

Repair is War on Entropy!