Don’t Overcharge Your Tool Batteries! 

Leaving your battery to charge all night long is one of those simple mistakes any craftsman can make, few of us, though, realize just how detrimental overcharging can be. The excess heat generated during overcharging can dramatically deplete the overall life and performance of your battery
, so, charge it until its full (most chargers will indicate charging time) and remove it. Give both your battery and charger a rest from overworking and overheating.