If you own the 18M with the external 12-24V power option, it has a charge port on the front right of the unit that supports COBRA chargers only. Do not use any other type of charger as the voltage and current regulation are specific to COBRA in supporting optimal battery life and number of charge cycles. COBRA offers three chargers: a single, 5-module, and 10-module option. The larger, multi-bay chargers, help reduce the number of power outlets used and can be built into permanent charging stations to assist companies with large quantities of COBRA modules.
To charge the module, place the charge plug into the charge port. The charge LED indicator will blink when charging and will go solid when finished charging. Once fully charged, the charger will only provide a small trickle charge as needed. However, it's always recommended to monitor your equipment when charging and to unplug your charger when fully charged. Charging a module from 0% to 100% takes about six hours. Note that the battery will lose about 0.3V per month max during storage, which equates to about 15% each life lost per month max.
Store charged LiPo batteries in a dry, climate-controlled environment. COBRA LiPo batteries only charge to 85%; however, to maintain a healthy battery for as long as possible, we suggest that you discharge them to ~50% before storing for long periods. There is no need to remove the LiPo battery as there is an open circuit and no current draw when the key is in the off position.