Battery displays for electric rotorcraft

1. One or more tangible, non-transitory computer-readable storage media having stored thereon machine-executable instructions to:

receive battery data from at least one sensor connected to a battery bank of an electric vertical takeoff and landing (eVTOL) aircraft, wherein the battery bank comprises a plurality of batteries;

compute from the battery data an available flight time remaining for the eVTOL aircraft;

compute a nominal flight time remaining, wherein the nominal flight time remaining excludes a reserve flight time; and

display the nominal flight time remaining to a pilot in a human-readable format.

2. The one or more tangible, non-transitory computer-readable storage media of claim 1 , wherein the machine-executable instructions are further to display an aggregate battery charge remaining for the batteries of the battery bank.

3. The one or more tangible, non-transitory computer-readable storage media of claim 2 , wherein the aggregate battery charge remaining comprises a multi-segment display.

4. The one or more tangible, non-transitory computer-readable storage media of claim 3 , wherein the machine-executable instructions are to provide per-segment hysteresis for the multi-segment display.

5. The one or more tangible, non-transitory computer-readable storage media of claim 4 , wherein segments of the multi-segment display represent approximately 10% of the aggregate battery charge.

6. The one or more tangible, non-transitory computer-readable storage media of claim 5 , wherein the machine-executable instructions are to unlight a segment at approximately 4% of the aggregate battery charge represented by the segment, and light the segment at approximately 6% of the aggregate battery charge represented by the segment.

7. The one or more tangible, non-transitory computer-readable storage media of claim 1 , wherein the machine-executable instructions are to measure current from the batteries, and if the current from a first battery varies from the current from other batteries of the battery bank above a threshold, infer that the first battery has encountered a failure condition.

8. The one or more tangible, non-transitory computer-readable storage media of claim 7 , wherein the machine-executable instructions are to omit the first battery from the nominal flight time remaining.

9. The one or more tangible, non-transitory computer-readable storage media of claim 1 , wherein computing the available flight time remaining comprises computing the available flight time for a current phase of flight or a current flight profile.

10. The one or more tangible, non-transitory computer-readable storage media of claim 1 , wherein the machine-executable instructions are further to compare the nominal flight time remaining to a flight plan and determine whether the eVTOL aircraft can complete the flight plan.

11. The one or more tangible, non-transitory computer-readable storage media of claim 10 , wherein the machine-executable instructions are further to display a convergence or divergence between current flight conditions and the flight plan.

12. The one or more tangible, non-transitory computer-readable storage media of claim 1 , wherein the machine-executable instructions are to display a “land as soon as possible” warning if the nominal flight time remaining is substantially zero.

13. A method of estimating remaining battery for an electrical vertical takeoff and landing (eVTOL) aircraft, comprising:

collecting voltage and current data from a plurality of batteries in a battery bank and disposed to provide flight power for the eVTOL aircraft;

computing a reserve energy required to provide a reserve flight time;

computing a flight condition-based total flight time remaining according to the voltage and current data;

computing a usable flight time comprising the total flight time less the reserve flight time;

and displaying the usable flight time to a pilot of the eVTOL aircraft.

14. The method of claim 13 , further comprising accounting for estimated battery health of the batteries.

15. The method of claim 13 , wherein the reserve flight time is selected to avoid damaging the batteries by drawing the batteries draining the batteries below a threshold state of charge.

16. The method of claim 13 , wherein the reserve flight time is selected to comply with a statutory or regulatory requirement.

17. The method of claim 13 , wherein the reserve flight time is between approximately 20 and 35 minutes.

18. An electric vertical takeoff and landing (eVTOL) aircraft, comprising:

a rotary drive system;

a power bank to power the rotary drive system, the power bank comprising a plurality of batteries;

a pilot display; and

a computing apparatus comprising a processor circuit and a memory, the memory having stored thereon instructions to monitor the power bank and compute a contextual nominal flight time remaining, wherein the nominal flight time remaining accounts for an aggregate status of the batteries and for a plurality of flight modes; and to display the nominal flight time remaining on the pilot display.

19. The eVTOL aircraft of claim 18 , wherein the instructions are further to subtract a reserve flight time from the nominal flight time.

20. The eVTOL aircraft of claim 19 , wherein the reserve flight time is selected to avoid damaging the batteries by drawing the batteries draining the batteries below a threshold state of charge and/or to conform to a statutory or regulatory requirement.