Electric power chairs and mobility scooters have enhanced the lives of millions of people, but a mobility scooter is only as good as the scooter battery that powers it. Designed to be durable and dependable, almost any mobility scooter battery will eventually need replacement. Today, almost all electric mobility devices use a 24 volt system consisting of an electric scooter battery pack made up of two 12 volt units linked together. The differences in batteries can be attributed to two factors; composition, and amp hour ratings.
There are several terms that are generally used to designate the differences in electric scooter battery composition. These refer to the physical size and properties of the batteries themselves, and do not relate to power output or between-charge longevity. Any of these modern types will give excellent service as long as they are properly charged.
Sealed Lead Acid (SLA) Batteries
Unlike the old wet cell monsters of the past that could be “topped-off” when required, today’s SLA batteries are maintenance-free, completely enclosed units where the electrolyte liquid (the battery acid) is completely sealed, which accounts for the term “sealed lead acid” as its common designation. Maintenance-free not only means no additional acid ever needs added, it also means that the electrolyte liquid cannot “boil out” or evaporate from out of the cells. The superiority of SLA batteries has long been recognized, and almost any scootmobiel goede accuused today is an SLA-type battery.
Absorbed Glass Mat (AGM) Batteries
With a technology originally developed for military aircraft, AGM batteries use a fiberglass like mat to hold the electrolyte in a stable and spill-proof suspension that isn’t as prone to suffering low voltage when exposed to cold temperatures. An additional advantage of the AGM system is the relatively quick recharge time. This is often the best possible type of battery for most scooters; however they may be damaged by being over-charged. Being hermetically sealed units, all AGM batteries are SLA batteries, but not all SLA batteries are AGM batteries.
The electrolyte in a gel-cell battery is not liquid, but is a gelatin-like semi-solid mass. Perhaps best known for being the preferred type of motorcycle battery, the gel battery offers several advantages over their AGM counterparts for scooter and power chair users. Not containing liquid, the gel battery will continue to work perfectly even if turned completely upside down. Without liquid acid, the gel battery produces no fumes and is the safest battery type for power chairs and scooters that are used primarily indoors. Additionally, a longer lifespan can be expected from a gel-cell.
The U1 is currently the most common size of mobility scooter battery. Note that the U1 designation refers only to a common universal physical dimension; 7.71″ length, 5.16″ width, 7.23″ in height, and can apply to SLA batteries of both gel and AGM construction. U1 power chair and electric scooter battery packs are commonly found with ratings ranging from 31 amp hour to 35 amp hour. There are also half-U1 batteries available in a variety of ratings.
Amp Hour Rating
The amp hour rating of a scooter battery is an indication of travel range and between charge longevity. A higher or lower amp hour rating will not affect the battery’s lifespan, nor will it change the scooter’s top speed. Any mobility scooter will operate with the same U1 battery pack as any other. Think of an amp hour rating as an indication of the time length of a usable charge, but not necessarily its strength or volume.
Some mobility battery chargers use a low voltage sensor which will not allow it to active if the voltage of the power chair battery pack is significantly below 24 volts. Attempting to use a fully charged 12 volt mobility scooter battery and a very low charge battery may not power your mobility scooter. For this reason it is very important to replace your scooter’s battery pack as a single unit; that is, to change both batteries at the same time instead of only installing a single new battery harnessed up to an older one.