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.
AA batteries are charged by plugging the batteries on to the electric charger. The chemical ingredients of these batteries store the electric current, which we use later on for various purposes. Typically, it may take 3 to 4 hours to charge any type of AA battery; however, all these depend on your requirements.