  The transient neutron star low-mass X-ray binary EXO 1745-248, located in the
globular cluster Terzan 5, was detected during its quiescent state with Chandra
in 2003. The source displayed a 0.5-10 keV X-ray luminosity of Lq ~ 1E33
(D/5.5kpc)^2 erg/s, which was completely dominated by hard non-thermal
emission. This is at odds with other non-pulsating neutron stars that typically
show detectable soft thermal emission at such quiescent luminosities. Here, we
use three additional Chandra observations, performed in 2009 and 2011, to
further study the quiescent properties of EXO 1745-248. We find that the
powerlaw intensity varies considerably up to a factor of ~3 within hours and by
about one order of magnitude between the different epochs. We discuss the
implications of the observed change in quiescent flux for the interpretation of
the hard powerlaw emission. Furthermore, we constrain the neutron star surface
temperature as seen by a distant observer to kT_inf < 42 eV and the thermal
bolometric luminosity to Lq,bol < 7E31 (D/5.5kpc)^2 erg/s. This confirms that
EXO 1745-248 harbours a relatively cold neutron star and suggests that, for
example, enhanced cooling mechanisms are operating in the stellar core, or that
the binary on average resides in quiescence for hundreds of years.
