Hi 3 tons,
I copied the temperature numbers from the Nasa site about the helicopter, so I expect we are both right.
There doesn't seem to be a lot of detail on the Nasa and other sites about what the specifications are on the battery bank. I would dearly love to know the makers name. Found it! Sony. These are Sony SE US1865o VTC4 Operating Temperature (cell surface): Charge 0 ~ 50 degrees Celsius , Discharge -20 ~ 75 degrees Celsius
I loved the microphone on the rover--the first time anyone has heard sound from another planet.
https://rotorcraft.arc.nasa.gov/Publications/files/Balaram_AIAA2018_0023.pdf6 Sony SE US1865o VTC4 Li-ion cells with a name plate capacity of 2 Ah. The maximum discharge rate is greater than 25 A and the maximum cell voltage specified by the manufacturer is 4.25 V. The continuous tested power load capability of this battery is 480 W with a peak power capability of 510 W. Battery voltage is in the range of 15–25.2 V and the total mass of the 6 cells is 273 g. A cell balancing charge management system controlled by the FPGA ensures that the all the individual cells are at a uniform voltage. A de-rated end-of-life battery capacity of 35.75 Wh is available for use. Of this capacity, 10.73 Wh (30%) is kept as reserve, night-time survival energy usage is estimated at 21 Wh for typical operation in the northern latitudes in the spring season, and approximately 10 Wh is available for flight. Assuming that 20% of the power is at the peak load of510 W and 80% is at a continuous load of 360 W, approximately 90 sec of flight is possible. These energy projections represent conservative worst-case end-of-mision battery performance at 0 C initial temperature. More moderate power loads will extend the flight time.
