Electric wheelchairs are used by millions of people, providing mobility for those who don’t have the ability to operate manual wheelchairs, and helping them to access challenging terrain including steep inclines. Electric wheelchairs can do all this by using battery power. Let’s take a detailed look at wheelchair batteries. We’ll discuss the different types of batteries used by wheelchairs, look at some of the pros and cons of each type, and provide some tips on how to maintain and charge them to get the best possible performance out of an electric wheelchair.
What Voltages are Used by Wheelchair Batteries?
When looking at wheelchair batteries there are two differentiating factors – chemistry and voltage. Let’s look at voltage first. Although all wheelchair batteries are 12 volts, most wheelchairs use a 24-volt system. That means that most electric wheelchairs require 2 X 12-volt batteries to run.
When purchasing a wheelchair battery, it’s crucial that both batteries have the same battery capacity and chemistry. Battery capacity is measured in amp hours (Ah). An amp hour is a measure of the amperage a battery can provide in one hour. This means that the bigger the amp hours rating of a battery is, the longer the wheelchair will be able to operate before having to be recharged.
What Type of Battery Do Wheelchairs Use?
Let’s now look at chemistry. Electric wheelchairs normally use one of two different types of batteries: gel batteries or deep cycle Absorbed Glass Mat (AGM) batteries. Both are types of SLA (Sealed Lead Acid) batteries. SLA batteries produce electricity by means of chemical reactions that take place between a sulfuric acid solution known as an electrolyte and the plates packed inside the battery. The difference between gel and AGM batteries is how the electrolyte inside the battery is stored.
In gel batteries, a silica additive has been added to the electrolyte that turns it into a gel-like mass. In AGM batteries, the electrolyte is kept in suspension by several fiberglass separators that keep the solution between the battery plates.
Another term that should be defined is deep cycle. Deep cycle batteries have been designed to provide sustained, small levels of power for longer periods. This type of cycle life makes it possible to use deep cycle batteries for hours at a time, and wheelchairs are therefore a great application for them.
Are Gel or AGM Batteries Better?
Gel batteries have several advantages over AGM deep cycle batteries. The first is that the overall lifespan of gel batteries is longer. Gel batteries typically last about twice as long as AGM batteries. Gel batteries are also able to hold a charge for much longer than their AGM counterpart and tolerate extreme temperatures better.
One perceived disadvantage of gel batteries is that they cost more to purchase than what AGMs do. If you however consider that gel batteries last much longer than AGMs, the overall cost of ownership tends to even out. Gel batteries also take much longer to recharge than AGM batteries. This is due to gel batteries having very specific charging requirements in that they should be charged at lower voltages to prevent overcharging.
How Long Does A Wheelchair Battery Last?
A wheelchair battery that is fully charged will be able to operate a wheelchair for about 8 hours and typically last between one and two years. The battery’s actual lifespan will however depend on several factors, including the amount of weight that is transported, how often the wheelchair is used, whether the wheelchair battery is charged properly and the type of terrain it is used on.
Where Can I Find Wheelchair Battery Chargers?
When charging a battery, the most important rule that should always be followed is to ensure the charger is compatible with both the voltage and chemistry of the battery. If you for example use two gel sealed 12 volt lead acid batteries in the wheelchair, the charger must have a 24 volt output and be compatible with gel batteries. Many modern battery chargers come with different selections to cater to different battery chemistries. When you use a charger with more than one setting, always ensure you’ve selected the right chemistry before starting to charge the battery.
Can Wheelchair Batteries Be Overcharged?
Both over- and undercharging batteries can be harmful. It is therefore important that you monitor the charging cycle to ensure the battery is charged for the correct amount of time. You may however also decide to rather use an automatic or smart charger. These types of chargers monitor the battery to ensure the optimum charge and will switch themselves off automatically to prevent overcharging the battery. Once the battery starts to discharge it will switch on to start charging again.
How Are Wheelchair Batteries Charged?
There are a number of things to be aware of when you charge and store a wheelchair battery.
- A wheelchair battery typically takes around 8 hours to recharge fully
- Before recharging deep cycle batteries they need to be discharged fully
- Batteries should not be stored in a discharged state but should always be stored fully recharged
- Before using a battery again, check that it is fully recharged
- Regularly check the battery for signs of deformation including corrosion
- Always store batteries in a dry, cool place
Where Are Wheelchair Batteries Tested?
If your battery struggles to hold a charge or doesn’t last as long as before, the battery should be tested. At A-1 Accredited Batteries, we offer free battery testing. Simply take your wheelchair battery to the nearest A-1 Accredited Batteries outlet and we’ll test it to determine if it needs to be replaced or is still viable. If you do need to replace the battery, we offer a wide range of wheelchair batteries, as well as a range of battery chargers for wheelchairs.