18650 - extending battery runtime by lowering power usage?

hi everybody,

thank you for the funny project. I'm trying to hook up an 18650 battery to the d1 and led display and also trying to figure out how to activate power sleep modes or something to extend battery life.

right now out of the box while showing the clock its consuming 88mA and while scrolling its about 40-65mA on the lowest brightness.

is there a way to extend the consumption or will this be forever a dream. the used 18650 battery shield has an USB input for charging and stay connected to the wall, but my idea was to create something mobile