Thanks for bringing the issue to us via this post and email.
Kindly be advised that Samsung Note 8 is a Quick Charge 3.0 technology. To achieve its max charging speed, we would advise you to use our Powercore speed series or our newer Powercore II series to charge your Note 8 as they all support Quick Charge 3.0 devices.
Meanwhile, the powercore+26800mah PD is only able to charge a PD enabled device effectively. If you do want to use it to charge a Note 8, it will charge at 5V/1A mode, which is not fast enough to you.
Hope it helps. Should there be further concerns or questions we could address, please feel free to contact us via "email@example.com".