According to OnePlus, “After Always-on Display dial is turned on, the screen remains constantly on. This will lead to increased power consumption. Battery life will be reduced by about half.” The good news is that the OnePlus Watch already touts an impressive battery life of about 14 days, or so the company claims.
Knocking it down to half means that you should be able to get 7 days, which means that you’ll only have to charge it once a week. That’s already very good compared to some other watches, like the Apple Watch, so even at 7 days it’s not such a bad thing. However, we know that some might still prefer having 14 days so if that is the case, then you’ll have to turn off the always-on display feature.
Alternatively, you could turn it off when you don’t need it and turn it on when you do, which means that your battery life should be kind of mixed, but either way, at least the option is there for users.