RE: 4.5 hour charge time???
The included charger's max rate is .8 amps.
Safe charge for the pack is 1C rate or 2.1 amps
So yeah it's going to take that long as the charger is such a low rate.
And yes you can buy a better quality charger that will safely charge the pack a 1C or 2.1 amp rate.
But just so you know, even at that, a fully depleted pack will take an hour or so to charge.