Which battery do you have ?
Does the charger have a led that changes colour during the charge process ?
Is the battery giving any voltage reading from the discharge pins at all ?
Don't want to teach peeps to suck eggs, however some batteries with a switch have to be turned on then plug in to mains to charge. A few people have forgotten this and find it charges ok when they realise this.
Most have a fuse on the discharge side and if blown will not show any output voltage fuse may be internal or excessible on the outside.
Not ruling out other faults if you have a digital volt meter (DVM) check the charger output when plugged in to the mains.
Electrically assisted bikes, trikes, etc.