Anybody uses ZeroLemon external battery - which is more of a power bank that the phone slides into? I have two, one is the 8500 mAh version, the other one I got for the S8 but it also fits the Plus model with a bit of grinding.
When the internal tiny 3500 mAh runs down, in the early afternoon if charged at 9AM, you can push a button and the external ZeroLemon power bank will start charging the internal battery. Sometimes there is a bug in it, you push the button, it will charge for 15 mins and quit, thinking the phone is fully charged but it's not, so sometimes you have to push it multiple times.
It's not as nice as 10,000 mAh ZeroLemon (or another brand) battery that completely replaces the internal battery in devices such as Note 4 or LG V20 but I think it's better than original because it makes the phone thicker and much easier to hold, and stock S8+ is very slippery.
When the internal tiny 3500 mAh runs down, in the early afternoon if charged at 9AM, you can push a button and the external ZeroLemon power bank will start charging the internal battery. Sometimes there is a bug in it, you push the button, it will charge for 15 mins and quit, thinking the phone is fully charged but it's not, so sometimes you have to push it multiple times.
It's not as nice as 10,000 mAh ZeroLemon (or another brand) battery that completely replaces the internal battery in devices such as Note 4 or LG V20 but I think it's better than original because it makes the phone thicker and much easier to hold, and stock S8+ is very slippery.