  We present new Chandra X-ray observations of the transient black hole X-ray
binary MAXI J1659-152 in quiescence. These observations were made more than one
year after the end of the source's 2010-2011 outburst. We detect the source at
a 0.5-10 keV flux of 2.8(8)e-15 erg/cm^2/s, which corresponds to a luminosity
of ~1.2e31 (d/ 6 kpc)^2 erg/s. This level, while being the lowest at which the
source has been detected, is within factors of ~2 of the levels seen at the end
of the initial decay of the outburst and soon after a major reflare of the
source. The quiescent luminosity of MAXI J1659-152, which is the
shortest-orbital-period black hole X-ray binary (~2.4 hr), is lower than that
of neutron-star X-ray binaries with similar periods. However, it is higher than
the quiescent luminosities found for black hole X-ray binaries with orbital
periods ~2-4 times longer. This could imply that a minimum quiescent luminosity
may exist for black hole X-ray binaries, around orbital periods of ~5-10 hr, as
predicted by binary-evolution models for the mass transfer rate. Compared to
the hard state we see a clear softening of the power-law spectrum in
quiescence, from an index of 1.55(4) to an index of 2.5(4). We constrain the
luminosity range in which this softening starts to fractional Eddington
luminosities of (0.18-6.2)e-5 (d/ 6 kpc)^2 (M/ 8 Msun), which is consistent
with the ranges inferred for other sources.
