`The $3 replacement "higher capacity" battery I bought off AliExpress for a Fitbit Alta HR has had a terrible battery life of around two days. I checked the iFixit site, and the battery sells there for $20. Now, after watching this video, I really suspect I was sold a useless dud. Possibly the same thing happened with my Nexus 6P battery.
So useful to watch, and do a little more research before just buying that cheap "genuine" or "higher capacity" replacement battery. You get what you pay (or don't pay) for.