Nitecore NL2150 – Rechargeable 21700 Li-ion Battery 5000mAh

Not always. High-drain tactical lights want the HP version, and i-series lights such as the P20iX, P23i and P30i want the HPi version, which has a different contact arrangement. Tell us which light you have and we will match the cell.

No, there is no USB port in this cell. It charges in a light that supports in-light charging or in a charger such as the Nitecore UM2.

Because a flashlight this bright draws serious current, and an unbranded or unprotected cell under that load is how people end up with a hot pocket. Nitecore cells carry protection circuitry and are matched to their lights.

Several hundred full charge cycles with normal use. What shortens a lithium cell's life here is heat: a torch left in a parked car in Dar ages faster than one used every night.

Around half charged, in a cool place, terminals covered. Never store one flat, and never loose in a pocket or a drawer with keys and coins.

Spare lithium cells travel in cabin baggage only, never in checked luggage, with the terminals taped or in a case. Check the count your airline allows before you travel.

Stop using it. A swollen or dented lithium cell should be taken out of service. Do not charge it, do not puncture it, and dispose of it through a proper recycling point rather than in household waste.

When runtime has dropped noticeably against when it was new, or when it will not hold a charge for a week unused. A light that used to last a night and now lasts an hour is telling you the cell is done.