Always use a battery charger that is compatible with the type of battery (NiMH, LiPo, Li-Ion, or LiFe) you are using. Never plug a battery into a charger unless you are sure the battery and charger are %100 compatible. Do not use any charger or battery that is visibly damaged in any way.
Consult our battery compatibility charts for recommended batteries.
NiMH
https://www.valken.com/assets/download-files/BatteryCompatibilityChart-NimH-v6-flat.jpg
LiPo
https://www.valken.com/assets/download-files/BatteryCompatibilityChart-LiPo-v7.jpg
Li-Ion
https://www.valken.com/assets/download-files/BatteryCompatibilityChart-LiIon-v2.jpg
Here several helpful videos to help understand airsoft batteries.
Battery overview
https://www.youtube.com/watch?v=3mi68SPh_uY
Battery Safety
https://www.youtube.com/watch?v=xmXICypON7U
Battery handling tips
https://www.youtube.com/watch?time_continue=1&v=6dWcPwjtRPE&feature=emb_logo