milwaulkee 18 battery charging help

Milwaulkee 18 v red Lon battery charger stoped working , so I pulled the charger pins block out , a plastic block with the terminals that insert into the battery when in charge mode , on the battery there is a b c d e pins , positive is A earth E so I wire these to a blug ,, I use the acucell 6 charger set on 18 volts 3amps as battery is , set on lipo charge All I get is broken circuit warning on the charger what am doing wrong , , I would had thought that + - into a charger would had done the job , help please