Roomba 4200 Series

I acquired a Roomba from a family member who never took it out of the box. Its a Discovery model - I plugged it in and has been for 24 hours now. It does not turn on at all. Is the battery just useless or should I invest in a new battery? I thought it would at least power on when tethered to the cord. Thanks for any help.

@jlynch, it could be the battery, we would suggest to try it out, if it has never been used the battery could be completely not functional to the point that it gives no power at all and can not recharge. Here is a link to the battery you need.