if you use protected batteries like in my past link you are safe from shortcuts overcharge/discharge and so fire/explosion is like a mobile's battery, if you want be 100% safe with your charger take it with USB input like that instead of AC
if you use protected batteries like in my past link you are safe from shortcuts overcharge/discharge and so fire/explosion is like a mobile's battery, if you want be 100% safe with your charger take it with USB input like that instead of AC