Lowest voltage drop diode possible
Check out the SM74611 Smart Bypass Diode from Texas Instruments.


  Forward Voltage:
  Vf[V] = 26mV @ 8A, Tj = 25°C


Other alternatives:

LX2400 Cool bypass switch (CBS) from Microsemi


  Typical Forward Voltage
  VF = 50mV @ 10A, Tamb = 85°C


SPV1001 Cool bypass switch (CBS) from STMicroelectronics


  Vf[V] = 120mV @ 8A, Tj = 25°C
  Vf[V] = 270mV @ 8A, Tj = 125°C


SBR30U30CT Super Barrier Rectifier from Diodes


  Vf[V] = 190mV @ 2.5A, 125°C
  Vf[V] = 250mV @ 5A, 125°C