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.
The battery industry standard is a 20 hour rate, i.e. how many amperes of current the battery can deliver over 20 hours at 80 degrees F until the voltage drops to 10.5 volts for a 12 V battery and 21 volts for a 24 V battery.