This question is rather complicated since your device's power consumption fluctuates a lot depending on if you are actively using the device or not using it at all. This affects the time and percentage Omnicharge can charge your device.
So to simplify the question, we use a more objective method by comparing Omnicharge's battery capacity to your device's internal battery capacity. Also considering the efficiency loss of Omnicharge's conversion circuits, the equation of charge percentage is:
Omnicharge's battery capacity / device's internal battery capacity * Omnicharge's conversion circuits efficiency
Take the Omni Mobile 9,600 and the iPhone 11, the Mobile 9,600 has a 34Wh capacity and the iPhone 11 has an 11.91Wh internal battery; the Omnicharges conversion efficiency is around 90%. Put these numbers in the above equation and we get:
34Wh / 11.91Wh * 90% = 2.57
This means that the Omnicharge can charge the iPhone 11 around 2.5 times. This is assuming that the phone is turned off or in sleep mode. Operating the phone while charging will impact this calculation.