I would say, put the computer in hibernation mode, Sleep mode it ok, but it will still drain power overtime a lot quicker.
Hibernation: shuts the computer down, but it saves your tabs,docs,and other opened items(not all)
sleep: turns off your screen but the computer is still on, thus using more battery.
But maby the best way to save power would be to shut it down , just depends on what you want to do.
Hope this helps. Have a great day!