Power Wheelchair Learning Center
Contents
- What is a Power Chair?
- What kind of Power Chair is best for me?
- How Do I choose the Features and Customizations of my Power Chair?
What is a Power Chair?
A power chair is a wheelchair that is powered by a battery operated electric motor. The user can drive and maneuver the power chair with little effort using a joystick controller. Power chairs offer independent mobility without the physical exertion that is characteristic of manual wheelchairs. Advanced customizations and varied controller options allow the freedom to be mobile even to users suffering from the effects of injury or illness who have very limited physical abilities. Power wheelchairs are significantly heavier than manual wheelchairs due to the additional weight of the power motor, battery and controls. They are therefore less portable than manual wheelchairs. Power chairs are often transported into a car by way of a van lift or ramp while the user is seated in the chair. Power chairs generally require more maintenance than manual wheelchairs and they are more costly.
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What kind of Power Chair is best for me?
There are many different factors that will help you to determine what kind of power wheelchair will be best for you. Consider where you will drive your power chair most often: will you be indoors, maneuvering in tight spaces and narrow hallways, or outdoors traveling over bumpy sidewalks, uneven roads, grass, and gravel. Your weight, the driving speed that you desire and your environment are important factors in evaluating how powerful a motor and what kind of batteries you should employ. Also think about you transport and storage needs.
Chairs with a power base are durable and dependable for long term benefits. They have varied seating options for all day comfort and are ideal for long term use. The location of the power wheels in relation to the user’s center of gravity will affect the driving characteristics of the chair:
For indoor and outdoor performance and fast driving speeds, choose a back-wheel power chair that will maintain balance and stability even on uneven ground surfaces like grass, carpet, or gravel.
The center-wheel power chair is designed for turning and maneuvering in challenging indoor spaces such as small apartments and narrow hallways and doorways.
Front-wheel power chairs are best suited for driving over rough terrain and surmounting obstacles such as curbs and bumps in the sidewalk, especially outdoors.
Heavier users will be comfortable and safe driving a strong, durable heavy duty power chair. Heavy duty power chairs also provide optimal performance when driving over extreme terrain.
Folding power chairs offer all day comfort and a degree of portability similar to a standard manual wheelchair.
For occasional or short term use, a travel power chair is convenient because it is weighs less and can be disassembled for easy transport.
If you will use your power chair for many hours a day you should consider investing in a seat cushion and other accessories for maximal comfort and convenience.
Choosing the Features and Customizations of my Power Chair
Configuration
Most power wheelchairs have a power base that consists of the frame, the motor, the batteries, and the wheels. A separate seating system is mounted above the power base.
The power wheels can be located in the back, center or front of the power base. The performance of the power chair will be impacted by the location of the drive system in relation to the user’s center of gravity.
The power wheels of a back-wheel power chair are located in the rear of the seat. This provides maximum stability and highest speed, up to 8.5 MPH. The back-wheel power chair will stay well balanced even on rough terrain, making it ideal for indoor and outdoor use. It has a larger turning radius than front and center-wheel power chairs, so it is more challenging to maneuver through narrow indoor spaces. The swiveling casters at the front of the chair limit some leg rest options.
Center-wheel power chairs have a six wheel design. The two power wheels are positioned in the center of the chair directly under the user. Casters are placed in the front and the back of the chair to provide stability. This innovative design creates the smallest turning radius, as low as 18 inches, to allow the power chair to turn and maneuver in small spaces in the house or office. The center-wheel power chair requires flat ground to maintain stability, so it is not recommended for uneven terrain or heavy outdoor use.
The front-wheel power chair’s power wheels are placed at the front of the chair, ahead of the user, with casters in the back. Since the power wheels are in front, the front-wheel power chair applies the most force to surmount obstacles in the road. It is the best power chair for climbing curbs and rolling over bumps and obstructions up to two inches high. It also offers more leg rest options than other power chairs. The location of the swiveling casters in the back causes the front-wheel power chair to fishtail at higher speeds. Front-wheel power is not available for heavy duty variations.
Some users prefer a folding power chair, a basic folding manual wheelchair frame that is motorized. A folding power chair offers the features and customizations of a standard manual wheelchair for all day comfort. Its main advantage is that it can be folded from side to side for easier transport and compact storage. The battery box is removed from the power chair before it is folded. Even so, the folded power chair is very heavy due to the added weight of the motor, joystick, and electronic control box. It is more difficult to lift than a manual wheelchair, and is a less popular choice overall.
Seating Systems
Power wheelchairs have either a captain seat or a rehab seat mounted above the power base.
A van style ‘captain seat’ looks like a vehicle seat with upholstery, padding and flip back armrests. The seat back sometimes flips down. The van seat is offered in different sizes and seat widths for a good fit. It cannot be customized to provide posture control or to accommodate advanced seating products. Therefore, a captain seat is suitable only for users who do not have special seating requirements.
Alternatively, specialized seating systems called rehab seats are available for users who need individualized support. The seat width and depth and the back height of the rehab seat can be greatly modified. Some models also offer an adjustable seat back that can recline on an angle. Rehab seats are constructed with just a seat pan without upholstery. A customized back support and seat cushion must be ordered separately. The rehab seat provides support, stability and posture control that is tailored to meet the user’s needs.
Elevating or tilt rehab seats are also available.
Arm rests
The multiple arm rest options that can be configured for a manual wheelchair are available for power chairs as well. Armrests provide comfort for the arms while seated, aid in independent transfers and assist in weight shifting.
Full Length Armrests (15 inches long) extend from the seat back until the front of the frame to fully support the user’s arms when seated. They also are helpful when transferring independently in and out of the wheelchair. A full length arm can be fitted with a full or hemi wheelchair tray.
Desk Length Armrests are shorter (11 inches long), providing support from the power chair back to three quarters of the seat. They allow the user to sit closer to a table or work comfortably at a desk. Desk length arms are not long enough to assist in independent transfers in and out of the power chair.
Removable Armrests can be disconnected from the frame of the power chair to permit a sliding transfer into the chair. They can also be removed to make the chair lighter to transport.
Flip Back or Swing Away Armrests can flip to the back or swing to the side of the power chair to allow easy access when transferring in and out of the power chair. Even when flipped back, they are attached to the frame so they will not be misplaced or lost.
Adjustable Height Armrests can be adjusted to the perfect height to support the user’s arms in a seated position. Arm rests that are just the right height are the most comfortable. Well adjusted arm rests promote good posture and minimize slouching or straining. Full length adjustable height arm rests can be quickly lowered to slide under a desk or table.
Leg Rests
Leg rests support the feet and legs of the power chair user. Many of the leg rest choices available for manual wheelchairs can be configured for power chairs as well. Some power chairs feature power adjustable leg rest options that can be easily and conveniently adjusted by the user.
Swing Away Detachable Leg Rests swing to the side for easier transfers. They also can be removed from the frame of the power chair for transport or storage.
Elevating Leg Rests lift up the legs to any angle to achieve maximum comfort. Each leg can be adjusted separately. A power chair with a reclining seat back needs to be accompanied by elevating leg rests. They are heavier than other leg rests, and increase the total weight of the power chair.
Some leg rests hangers have Adjustable Rigging to adjust the height between the seat and the foot plate from 14-18 inches.
Standard Footplates constructed of aluminum or plastic and will support the foot from the heel until the ball of the foot. Adjustable angle footplates are longer, holding up more of the foot. Their front to back and side to side angle can be repositioned for enhanced comfort. Often, heavy duty power chairs feature Extra Heavy Duty Footplates that can bear the greater weight of the foot.
Some leg rests include Calf Straps or Heel Loops for safety and comfort.
Head Rest
A head rest can be added to a captain seat or a rehab seat for enhanced support.
Wheels
Power chairs have two power drive wheels that are 12-14 inches in diameter and 2-4 inches wide. Wider wheels have better traction and are more stable on rough terrain. Standard casters for a power chair are 8-9 inches in diameter and 1-2 inches wide.
Tires can be pneumatic, solid/foam filled flat free, or semi- pneumatic air tires with flat free inserts.
Pneumatic or Air Tires have the best traction and give the smoothest ride over rough or uneven surfaces. They are well suited for outdoor use on sidewalks, roads and grass. The air filled tires are softer, demanding more power from the motor to turn and roll. Air tires need to be refilled regularly and they are always at risk of getting a flat tire.
Solid and foam filled flat free tires are very easy to roll and turn on hard, flat ground, but they do not ride as smoothly on rough or uneven surfaces. They require very little maintenance. Solid flat free tires are the ideal choice for indoor use.
Semi-Pneumatic or Flat free inserts are air tires with a semi-solid core. They are harder than an air tire, but are still soft enough to ride smoothly over rough terrain. Semi pneumatic tires wear out sooner and may need to be replaced during the lifetime of the power chair. They are the popular choice for a power chair that is intended for regular indoor/outdoor performance.
Motor
Your weight, the terrain you will be traversing, and the driving speed that you want to achieve will help to determine what kind of motor you will need. Heavy duty motors are recommended for larger users or for extreme terrain.
Weight Capacity
Standard power chairs have a weight capacity of 250-350 pounds. For heavier uses, heavy duty power chairs support a weight capacity up to 650 pounds.
Portability
Most power chairs are quite heavy, ranging in weight from 90 to 240 pounds. The combined weight of the frame, seating system, motor, batteries, controller, arm rests, leg rests and user means that transporting a power chair by car is a challenge. Many power chair users opt for a van lift (if tiger offers this product, make a link) or a ramp that lifts the power chair into the vehicle while the user is seated. A lift or ramp will load the power chair without the physical exertion of disassembling and carrying the unit. The user can remain comfortably seated for the whole trip instead of transferring into the car and then back into the power chair. However, a van lift is a costly investment that not all power chair users can afford. It also limits the power chair user to travel only in vehicles that are properly equipped.
For infrequent or short use, a travel power chair is another alternative. Travel power chairs are lighter than regular power chairs, weighing between 80-100 pounds. Many models are can be quickly taken apart into three or four smaller more manageable pieces. Each piece weighs less than 50 pounds to make it to the trunk of a car simple. Travel power chairs are more portable but they are not intended for all day comfort or long term usage.
Some users will choose a folding power chair for greater portability without compromising on comfort. The battery box is removed from the frame to reduce the total weight and allow the chair to fold. Even with the battery box removed, the folded power chair weighs 80-100 pounds and can be difficult for many people to lift into the trunk of the car.
Batteries
Most power chairs are motorized by two 12 volt deep cycle lead-acid batteries that supply a total of 24 volts. These batteries are always used in pairs, and also needs to be replaced in pairs.
There are three kinds of lead-acid batteries that are suitable for power chairs: wet cell, gel cell and AGM.
Wet cell lead-acid batteries provide the most power per charge, are the cheapest, and weight the least. They supply maximum power for riding over extreme terrain. However, they require regular maintenance as the acid level of the battery needs to be checked often. The battery acid can leak, causing corrosion to the frame of the chair and dangerous exposure to the user. Because of their hazardous chemical composition, wet cell batteries are not approved for air travel and need to be stowed in a special locked container.
Gel cell lead-acid batteries are more popular because they are safe and maintenance free. They provide sufficient power for regular indoor and outdoor terrain. Gel cell batteries will not leak at all, and are permitted on board air craft. They also have a longer life. Though gel cell batteries are heavier and more expensive, they are still the preferred choice of most power chair users.
AGM (absorbed glass mat) batteries are a newer option for power chairs. AGM batteries are maintenance free, can’t leak and are approved for air travel. They are shock resistant and release minimal gasses when charging. AGM batteries operate better than other batteries at temperatures below 32 degrees Fahrenheit. They are most susceptible to over charging, and are very expensive.
Batteries for power chairs are available in various sizes, in order from the smallest to largest: U-1, 22NF, group 24 and group 27. A bigger battery has a greater charge capacity, larger range and more power potential. Bigger batteries are also heavier, increasing the total weight of the power chair. For batteries that are in good condition, charging over night should supply power to last the whole day. The range or distance that can be covered with a full battery charge depends on the age of the batteries, the condition of the power chair, the weight of the user, and the terrain. Frequent turning and driving up slopes will drain the battery faster. Power chair batteries are generally guaranteed for a year, but they may last up to 2-3 years.
Speed
The driving speed of a power chair is affected by the slope and difficulty of the terrain, the weight of the user, and the condition of the battery. Rear wheel drive power chairs are the fastest, driving at speeds up to 8.5 MPH. Other power chairs drive at average speeds of 4-5 MPH. Travel power chairs have lower speeds, between 3-4 MPH.
Controller
The most basic controller is a joystick mounted near the arm rest of the power chair. On many models, a swing away joystick mount facilitates easy transferring from the side and allows the user to come close to table or desk. Users who are not able to manipulate a joystick can utilize other input devices to control the power chair. Head controls, foot controls, chin controls, finger controls, touch pad controls, speech controls, and highly advanced sip and puff systems can be specially configured to give independent mobility to the most limited users. Occasionally, attendant controls are mounted on the back of the unit to allow a care giver to operate the power chair from behind.