We have received your NITECORE EC11 for warranty service and we thank you for your continued use of NITECORE flashlights.
We have completed testing on the EC11 and the flashlight is working as intended. Over 48 hours, a fully charged 18350 battery experienced less than 1% battery drain without use. This is normal as the circuit switch will draw a small amount of current anytime a battery is placed in the light and the tail cap fully tightened.
I know that you are already aware that the 18350 battery is an unprotected IMR and cannot be fully discharged without risk of going dormant. I have listed a couple more recommendations:
1. An IMR battery can also be over-charged which could cause the battery to fail. It is important that the charger you are using is reading accurately and has shut off protection when the battery reaches capacity or that you remove the battery from the charger when full charge status has been reached.
2. With a small size and high output and low milliamp battery (700 mAh), the EC11 is only capable of a maximum of 30 minutes of continuous operation when using the 900 lumen turbo setting and a fully charged battery, before the battery will be completely dead. To put this in perspective, when using the IMR 18350 battery, the EC11 can maintain an output of 900 lumens for 3 minutes before the heat protection circuit kicks in and drops the output of the light down. This 3 minutes of operation has used 25% of the total capacity of the battery, and 35% after 5 minutes. Since the usage is not continuous, if you run the light at turbo only 3-4 times for 3-5 minutes at a time, the battery can become completely depleted. It is recommended that an IMR battery be charged regularly and consistently, regardless of usage time.
We have cleaned and lubricated and are returning the light with a fully charged NITECORE IMR 18350 replacement battery as well as a fully charged NITECORE NL166 16340 battery. While the NL166 battery will not reach the full 900 lumen output, it will still provide ample brightness as well as a longer overall run-time and is protected against over-charge and over-discharge.