iRobot Roomba 510 battery charge not detected

Hello,

I have this old roomba, it worked perfectly fine until now stopped. As soon as I start the cleaning cycle it stops with a red light indicating battery needs to be charged. But battery is fine, quite new (replaced it) and when I dismounted it and i check with a tester it is fully charged (I think it gave me like 19,2V, don’t remember exactly because i did the check some time ago, before knowing this web, but it was a bit higher than battery V, what was indication of fully charged). So the battery is loaded, but the robot doesn’t detect the charge and stops working.

Regards