modality - a method of therapy that involves physical or electrical therapeutic treatment. rehabilitation - the treatment of physical disabilities by massage and electrotherapy and exercises.
Alkaline AA batteries are rated 1.5 volts, while NiMH AA batteries are rated at 1.2 volts. NiMH generally refers to a battery being rechargeable and to the materials from which the battery is constructed.
At the point where charge current has gone as low as it is going to, then the batteries are truly full. While 2% of Ah rating is close, good batteries will reach a steady state current at less than 1% of Ah rating. Once a battery is full, a lower voltage should be applied that will maintain the full charge. Depending on the type of battery, (liquid, gel), and the age of the battery, 13.4 - 13.8 Volts is appropriate as a float voltage.