The Nitecore D4 is compatible with a wide range of batteries, including Li-ion (Lithium-ion), NiMH (Nickel-Metal Hydride), NiCd (Nickel-Cadmium), and other cylindrical batteries.
Yes, the D4 features built-in safety mechanisms, including overcharge protection, short circuit protection, and temperature monitoring, making it safe to leave plugged in.
Charging speed varies depending on the battery type and capacity. Generally, the D4 provides fast and efficient charging, often completing charges within a few hours.