The Edyn devices are powered by lithium rechargeable cells, similar to the type used in cell phones, drones, electric cars etc. Lithium cells do NOT have an unlimited lifespan. The lifespan of a lithium cell begins on the date of manufacture, and will exhibit signs of degradation anywhere from 1 to 7 years depending on usage conditions. Battery degradation will typically be observed as an increase in discharge rate.
Some strategies to increase the lifespan of a lithium cell and reduce degradation are:
1) Do not expose the cell or device to temperatures outside 32-100F.
2) Do not allow the device to discharge to 0% and remain there for extended periods of time. NB: when a device is OFF or in the box, it will discharge over time to 0%.
3) Do not expose the device or cell to rapid temperature swings.