How to tell iff batteries are uselss or need replacing or charger or drill itself

The first thing to do is get your volt meter and check if there is any voltage coming from the battery and compare that to what it is stopped to be. If the voltage is ok, install the battery in the drill and try to run it. If it won't run, you've got a bad drill. Next install the battery in the charger and plug the charger into your wall outlet. There should be an LED which flashes to indicate that it is charging. If you can get a full charge on the battery (verify this with your volt meter), try it in the dill again. If the drill will not rotate, there is definitely a problem with the drill.