In addition, nickel-cadmium aircraft ships batteries are serviced periodically, using the deep-cycle method.
Very necessary for continued long term service.
Also, normally in service (IE: in the aircraft), they are pulse charged, using a higher than normal DC voltage.
38VDC, in one aircraft type (L1011).
And, these batteries should absolutely not be stored in the same environment with flooded lead-acid types.
Many precautions, with bad results (read: danger) if not followed carefully.
Many pilot dismiss their ships battery (or, batteries), by perhaps thinking...'it's only a battery, no harm, no foul.'
VERY far from the truth.