If the iphone 7’s battery is around 2000mAh, shoulnd’t the 10000 support about 5 charges?
Yeah so the power banks are only about 60-70% efficient in terms of capacity to power.
Oh ok, that makes sense then. Thanks!
To further expand on @joshuad11’s comment, the reason that you don’t get the full 5 charges is because there is some energy lost as the voltage is converted from the 3.7V that the power bank holds to the 5V that your phone’s input needs. Your phone than converts that 5V it’s receiving back to the 3.7V that your phone’s battery uses.
If your phone is on and connected to the power bank, it may start doing some more processor-intensive activities (cloud backups, app updates, background refreshes, etc) which further reduces the usable energy from the power bank.
All great answers for a very common question!
Thanks to everyone for clearing this up!