GVII - Extending the life of your Main Ship’s Batteries
From the Gulfstream Journal, January 2020, p. 6:
The battery service life and electrolyte consumption of Ni-Cad Batteries will vary depending on the duty cycle, average ambient temperature, and charge method utilized. The Gulfstream large cabin family of aircraft implements Ni-Cad Batteries in the Left/Right Main Ship Battery (MSB) positions. G650/G650ER and G500/G600 also have an Electrical Backup Hydraulic Actuator (EBHA) Battery.
Gulfstream suggests the following recommendations to prolong the life of these batteries:
Duty Cycle. Battery life is negatively-impacted with higher utilization. While both Left/Right MSBs are used to support aircraft power on and Aux Hydraulic Pump operation, the Left MSB is used to assist an APU Start. As a consequence, the higher duty cycle experienced by the Left MSB will result in lower service life compared with the other Right MSB. The EBHA Battery will mostly remain as a backup power source with a much lower duty cycle compared with the MSBs. Gulfstream Recommendation: an effective way to compensate for the difference in duty cycle between the Left and Right MSB is by doing a scheduled rotation that will swap both MSB at a given interval. That practice will contribute to balance and maximize the life between both MSBs. Another important recommendation to reduce the duty cycle on MSBs is minimizing the time spent on batteries only and avoiding running the Aux Hydraulic pump for extended durations.
Average Ambient Temperature. Intrinsic to the Ni-Cad technology is the fact that battery life will reduce with the increase of average ambient temperature. A rule is that battery life is reduced in half (TBC) for every 10C° increase in average ambient temperature. Gulfstream Recommendation: operators may want to consider removing the battery from the aircraft and keep those in ambient room conditions in case of prolonged parking in hot weather conditions.
Charge Method. All Gulfstream large-cabin aircraft utilize a dedicated Battery Charger to charge each battery individually, and this is considered by battery manufactures the best method to ensure a longer battery life in the field when compared with float charge.