Wolfpack – Submerged Electric Power Times and Ranges

Estimates of range and run times of electric propulsion.

Summary

All credit goes to GenXGamer !

I did some experiments to see what the discharge rates where for various loads.

These are my observations of the battery times for submerged travel.

Submerged depth was around 20 – 30 meters in a straight line.

Testing was based on the battery current meter (not motor RPM) to see what the general battery discharge rate was for

• 1kA Low Power
• 2kA Medium Power
• 3kA Full Power

Test Process

Conditions before start of each test:

1. Stationary, rudders centered, surfaced, full compressor, fully charged batteries, engines off and decoupled, electric motors off, screws engaged.
2. Mark position on map.
3. Stationary dive order to 30 meters.
4. Start timer.
5. Start both electric motors forward.
6. Run until drained to zero
7. Order to surface right as lights are turning off (so the dive panes are in correct position to surface when power goes out)
8. Power out, timer off.
9. Mark position on map when velocity reaches zero.

After the test:

1. Disengage screws
2. Recharge the batteries to full
3. Recharge compressor and prep the ballast tanks.
4. Repeat the test at a different power level

Results

Full Power

• Battery current draw: 3 kA.
• Total run time: 24 minutes.
• Speed: 7.7kn
• Distance traveled: 5500 meters

Medium Power

• Battery current draw: 2 kA.
• Total run time: 34 minutes 45 sec.
• Speed: 6.6kn
• Distance traveled: 7070 meters

Low Power

• Battery current draw: 1 kA.
• Total run time: 1 hour 8 minutes.
• Speed: 5.2kn
• Distance traveled: 10760 meters

Conclusions

• Going full power (full speed) over medium power (great speed) provides almost negligible benefit in speed (1 knot) at twice the battery burn rate. It should only be used in a dire emergency to dodge depth charges.
• A grid square is a good reference for the submerged range at full power. I circle with the radius of 5500 meters fits nicely into one grid square.
• Two full power tests where done with lights on and lights off. Shutting off power to lights did not seem to have an effect or the effect was negligible. Time was the same for both, 24 minutes. I did not test lights on/off during low power run.
• Recharging takes 6 minutes at dual engine max recharge rate.