i got 5 dc fan having 12v and 15w power and on battery bank i used battery of 125 amp. But problem is that fans are slow and wire length is about 170 ft. Charger of battery is 10amp(intelligent). kindly any one tell me about where is the problem,

 

hi,
Each fan draws 15W/12V = 1.25A, so 5 fans = 6.25A.

What gauge is your 170ft wire length.??

 

Along the same line of thought, try measuring your voltage at the fans.