direct fan replacement for Battery Charger (OPUS BT-C3100) 

OPUS Cooler Battery Charger Fan Replacement for Opus BT-C3100  

rated 12 V 
current 0.07A works fine if you are replacing 0.4

12V 2Pin 25mm 7mm 2507 1" 5 Blades Mini Small DC Brushless Cooling Fan


fan thickness is 7mm