Looking after your battery
The most common type of battery in a modern bike light is the lithium-ion (Li-ion) type. The beam strength or flash setting you select will dictate how much run time you get from the battery. Most lights will give you several hours on the lowest or flashing settings, but as soon as you move from lit streets to darker lanes, you’ll probably need the brightest setting, which can significantly reduce the run time.
The lifespan of a Li-ion battery is between 300-500 charge/discharge cycles. It’s obviously impossible to say how many years that equates to because it depends how often it’s used.
Li-ion batteries do not have a charge ‘memory’, as the older type of Nicad batteries did, so it is not necessary to completely discharge and charge them. Many manufacturers recommend charging little and often, with the occasional complete discharge so that the battery’s power gauge can recalibrate.
During the summer, it’s best to store a Li-ion battery in a cool place at about 40 per cent charge. Storing it ‘flat’ will reduce its capacity.