An intrinsic germanium detector was used to measure the beta endpoint energies of heavy fission products supplied by the on line mass separator OSTIS installed at the high flux reactor of the Institut Max von Laue-Paul Langevin, Grenoble. The endpoints of singles-spectra have been determined and, by means of beta-gamma coincidence measurements also most of the Ot~-values of the following neutron-rich nuclides could be deduced with high accuracy: