Understanding how power wheelchair batteries work is important for anyone who uses a power wheelchair. The wheelchair battery plays a large role in how the wheelchair performs, and since the batteries need to be replaced periodically, understanding the battery will help you select the correct replacement battery.
Power wheelchair batteries are typically “deep cycle” lead-acid batteries, meaning that each discharge cycle is meant to use most of the available capacity of the battery. Deep-cycle lead-acid batteries have 3 main characteristics: capacity, current rating, and cell type.
Capacity determines how long the battery will function, and is noted in ampere-hours (Ah). A typical deep-cycle lead-acid battery has a capacity range from 30 to 90 ampere-hours, or about 3-9 hours of continuous use of an electric wheelchair that runs on 10 amperes. It is important to note that few people use their wheelchair continuously.
Battery current, or the rate of electron flow, is expressed in amperes (A). Basically, the larger the current rating, the greater the ease for the power wheelchair to travel over rough terrain and obstacles.
Cell type indicates whether the power wheelchair battery is wet-cell or gel-cell, the two main types of wheelchair batteries currently available. Both may be used in a power wheelchair, although manufacturers typically recommend gel-cell batteries due to maintenance and environmental concerns with the wet-cell type.
Despite these concerns, wet-cell batteries usually have a larger capacity, can provide more power, and usually cost less than gel-cell. For these reasons, they are still the battery of choice for many users. Wet-cell batteries are available in vented and sealed versions:
* Vented wet-cell batteries must have water added to the battery on a regular basis, due to water evaporation over time. This is often difficult, since the person doing the maintenance is exposed to battery acid each time the battery case is opened to add water. Doing this increases the risk for chemical burns. Chemical spills can also lead to wheelchair corrosion.
* Sealed wet-cell batteries do not need to have the water level maintained, since they are a closed system. But the possibility still exists for chemical spills, due to cracks in the battery case or the battery boiling over. Neither type of wet-cell battery is allowed on aircraft.
Gel-cell lead acid batteries are maintenance free, and have no possibility of chemical spills, so are easily able to be transported on aircraft. However, there is a disadvantage to gel-cell batteries and that is that they generally have 10-20% less capacity than wet-cell. They also usually cost more. But if the wheelchair user does not typically travel long distances each day, gel-cell batteries will likely be the best option.
One should also consider the battery charger when buying new power wheelchair batteries. It is important to make sure you have the correct charger for the type of battery you are using, since the wrong battery charger can cause permanent damage to the battery. As a deep-cycle battery, wheelchair batteries are meant to be almost completely drained before recharging. Most batteries can be recharged as much as 300 times before they must be replaced.
To insure that your wheelchair always operates at it’s best, have a good understanding of your power wheelchair batteries to help you purchase the best replacement battery for you.