A determining factor in the range and power of a powered chair. Generally, the larger the chair’s batteries, the greater the power and the longer the chair’s range between charges. Many chairs require two rechargeable 12-volt batteries. Most wheelchairs utilize U1, group 22 or 24 batteries, although other batteries are also used. More manufacturers are designing chairs around the group 24 battery because it affords a longer range. The type of battery required is also an important consideration in terms of safety, maintenance, and transport. Powered chairs may utilize lead acid, gel cell, or sealed wet batteries. Gel cell batteries require the least maintenance and have less danger of leaking than do the other battery types. Gel cell batteries are also required by a number of airlines when transporting powered chairs.