citroen picasso battery charge fault?

i found when i was out driving today that the dash would beep and flash up battery charge fault intermittently i found the more i switched on loading wise i.e. air con, lights, heater etc.. it was staying on does this mean a faulty alternator? i would say the battery was at fault but i replaced it only over the winter....there was also a faint electrical burning smell. after switching oneverything in the car (whilst the engine was running of course) the charge fault was displayed so i switched off then tried to restart i have flattened the battery so it wont even turn over.....any suggestions anyone?