A new experiment is being prepared at the Mainz Microtron (MAMI) to determine the $\Lambda$ binding energy of hypertriton. The energy will be measured by the spectroscopy of mono-energetic pions from two-body decays of stopped hyperfragments. During the last decade, it has been demonstrated at MAMI that this technique yields an unprecedented precision. The new experiment makes use of a novel high-luminosity target that takes advantage of the low density of lithium to minimize momentum smearing for the outgoing pions. With a beam energy determination by the novel undulator light interference method an improved calibration of the magnetic spectrometers can be reached to reach the goal of a statistical and systematic error of $\sim$ $20\,\mathrm{keV}$.