Charging system on most cars works by pushing power from the alternator through the voltage regulator and then to the battery.

If the VREG is dead, your car could do this. Overcharging of the battery. Then you will get the smell too as the battery thinks about blowing up do to the over voltage.

Check voltage when car is running - replace battery most likely needed - and maybe alternator. But it's probably the battery sir. You can take it out and have it tested at a store.