Ego and MOD batteries are high capacity and they do take several hours to fully charge. The higher the mAh rating the longer it will take to charge the battery.

Ego batteries:
It could be a defective USB Charger or Wall to USB Adapter. Try using the USB charger on a computer USB port or a wall to usb adapter from a cell phone if available. If it charges quicker then, we can rule out the USB charger.