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 voltage on a fully charged battery should be about 12.7-12.8 volts. If it's higher, the charger is on. Batteries will usually fail to start an engine at 12 volts or less. This is dependent on the age of the battery. A new, but depleted battery may only fail to start at a voltage as low as 11.5 volts. Be wary of electric panel meters; they are often very inaccurate.