Robot Vacuum, needs repair (Elm Park RM12)

iRobot Roomba 660 Robot Vacuum, probably needs new battery.

Found our Roomba in the loft. Was working fine when we put it in 4 years ago but puts up an error message after 20 minutes of charging. I think it just needs a new battery. Looks very easy to change.

And looks like you can get one for £30 or an official one for £80 from iRobot.

If you're interested I have links to the instructions and to the sites you might buy a new battery from that I can share with you.