STATED SERVICE LIFE

Manufacturers of rechargeable Li-ion batteries typically claim a lifetime of 500 full charge cycles before the usable capacity drops to 80% of the original value. Depending on the frequency of use, this may correspond to 4-10 years of operation.

HOW DOES A LI-ION BATTERY AGE ?

Batteries age naturally from manufacture due to the chemical reaction of the electrolyte with the anode material. However, many things can accelerate aging. During aging, the internal resistance of the battery increases and its usable capacity decreases.

WHAT INFLUENCES AGEING ?

Li-ion cells, like all other rechargeable batteries, do not like frost. Low temperature increases the internal resistance of the battery and reduces the capacity. Li-ion batteries work in freezing temperatures, even at -20°C, but their usable capacity is reduced (but not drastically) and they are destroyed (aged) by such use.

The aging of a Li-ion battery greatly affects the charge and discharge current. You can influence the charging current, for example by choosing a gentle, slow charger, such as the C/5 we use for our headlamps. You are then limited only by the slightly longer charging time, from zero to full 7.5h, which is still acceptable.

The discharge current doesn't affect much, if you want to shine at maximum, the discharge current will logically be higher.

TIPS FOR MAXIMUM LIFE EXTENSION

Li-ion cells, like all other rechargeable batteries, do not like frost. Low temperature increases the internal resistance of the battery and reduces the capacity. Li-ion batteries work in freezing temperatures, even at -20°C, but their usable capacity is lower (but not drastically so) and they are destroyed (aged) by such use. The first recommendation is therefore to avoid use below 0°C, the battery case can always be hidden under the top layer of clothing or use the protective pocket we make against frost.

A partial discharge is better than a zero discharge. Ideally, never discharge the battery completely to zero. If such a situation occurs, then recharge the battery immediately.

Long term storage is best in a cool place (10°C) and at partial charge (ideally 70%).

Only charge at normal room temperature of 15-25°C.