5800 original charger output is 890mA.  It should take 1 hour and a half to fully charge our 1320mAh battery.  If you use older chargers / chargers for other phones with lower output, it will take longer.  Those chargers for lower end phones will take hours to fully charge your 5800.  Of course, if you have some app running (like the Night Stand), it will affect your charging time.