Batteries will become unfit to use after they’ve been in the water. Usually however, a battery won’t leak inside the washing machine thanks to the safety valve - so chances of your textile being affected are minimal.
The capacity of batteries is indicated as XXXX mAh (milliampere/hour). If you insert this battery into an appliance which consumes 100 milliampere current continuously, the operating time of the appliance will be around 20 hours mathematically.
The memory effect is an occasional defect, which occurs in Ni-Cd and Ni-MH rechargeable batteries, where the maximum battery voltage decreases even though the original power of the battery remains the same.
This is a vibration noise which occurs when electric current flows through a transformer or a winding wire inside a component part. However, the charger may still be used without any concern as there is no need to worry from a safety point of view.