Phil - Very useful information here. Do you know the model number of the LiPo battery that fits inside the plastic case that comes with the mbot? The one I have works fine but is just a bit too long to fit inside the case. Thanks!
I have found that a good alternative location for your Lopo battery may be under the body of the mBot between the motors... this worked quite well for my mBot that is if you can't find the right battery for the box supplied I had this issue.