Scooters and e-bikes have quite a few sizes of batteries in them. There are universal batteries that fit them, and batteries specifically designated for electric vehicles. They look very similar and both will fit.. The difference is in the quality of construction, and how long they will last.
The cheap ones are good for about 100 cycles ( discharge and recharge is one cycle) and the proper ones are good for 300 to 500 cycles and cost more. The good ones have a designation in the part number indicating they are specifically for electric vehicles.
What batteries your scooter, wheelchair, or e-bike takes, depends on the make and model. There is a variety of sizes. The very best way to know what they take is to look at the part number on the existing batteries. There will be from 2 to 6 batteries in various models, depending on the voltage and size of the scooter, and they are all available in both the cheap and good quality.
A typical 48 volt moped will have 4 batteries in it. These range from $50 to $90 each, and their lifespan corresponds to the price you pay for them. It is hard to rate them in time (like say a year), because each user is different.
If you use it daily, then the cheap ones last about 3 months, and the good ones will last about a year. This is based on the cycles.
If you only used it on the weekends, then you could get 2 years (100 cycles) from the cheap ones, and the good ones could go 8 years. (400 cycles)
It absolutely matters that you make sure you know which type of quality batteries you are buying. We can show you the pros and cons of each, as well as install them for you.
If you have questions about your specific application, just call or come down for your options.