We use Polystingers in our patrol vehicles, and we have found that leaving them in the chargers continuously will kill the battery sticks. Try to not leave your Stinger in the charger like that - either lift it up and turn it so the contacts on the light body do not meet the charger contacts, or carry it in a pocket or in a belt holster. You may want to replace the NiCd battery stick with a NiMh battery stick for slower drain-down and longer run-time. Either that, or look up on CPF for the threads on converting your Stinger (not XT) to use li-ion cells.