Batteries are "perishable goods" and require a certain care, e.g. to avoid deep discharges and thus their destruction.
Therefore, single-battery lights should have been mounted or recharged no later than 3 months after delivery.
On the carton label you can see by a code when the light was delivered.
The code is structured as follows:
Example: "12B1"
12 = calendar week
B = stands for 2
1 = current calendar year.
The luminaire was then delivered in week 12/21.