Tỷ lệ phần trăm hàng năm của các pin NiCd đòi hỏi phải thay thế khi được sử dụng mà không cần bất kỳ bảo dưỡng giảm với tập thể dục và tu sửa lại. Các thống kê này được rút ra từ pin được sử dụng bởi Hải quân Hoa Kỳ trên các tàu sân bay USS Eisenhower, tàu sân bay USS George Washington và USS Ponce. | Maintenance Method Annual Percentage of Batteries Requiring Replacement Charge only charge-and-use 45 Exercise only discharge to 1V cell 15 Reconditioning secondary deep discharge 5 Figure 10-4 Replacement rates of NiCd batteries. The annual percentage of NiCd batteries requiring replacement when used without any maintenance decreases with exercise and recondition. These statistics were drawn from batteries used by the US Navy on the USS Eisenhower USS George Washington and USS Ponce. The GTE Government System report concluded that a battery analyzer featuring exercise and recondition functions costing 2 500US would pay for itself in less than one month on battery savings alone. The report did not address the benefits of increased system reliability an issue that is of equal if not greater importance especially when the safety of human lives is at stake. Another study involving NiCd batteries for defense applications was performed by the Dutch Army. This involved battery packs that had been in service for 2 to 3 years during the Balkan War. The Dutch Army was aware that the batteries were used under the worst possible conditions. Rather than a good daily workout the packs were used for patrol duties lasting 2 to 3 hours per day. The rest of the time the batteries remained in the chargers for operational readiness. After the war the batteries were sent to the Dutch Military Headquarters and were tested with Cadex 7000 Series battery analyzers. The test technician found that the capacity of some packs had dropped to as low as 30 percent. With the recondition function 90 percent of the batteries restored themselves to full field use. The Dutch Army set the target capacity threshold for field acceptability to 80 percent. This setting is the pass fail acceptance level for their batteries. Based on the successful reconditioning results the Dutch Army now assigns the battery maintenance duty to individual battalions. The program calls for a service once every two months.
