@mahsel, the voting power increases by 20% over the existing power and not directly to 100% in 24 hours. That happens when you use only 10 upvotes of 2% each everyday. In that case your voting power becomes 100% next day again.
So it is your present power x 20% you get for next day. So with your present power u need to wait for 3-4 days to get to 100%. In mean time do not upvote for anyone for next 3-4 days till u get your 100% power. After that upvote only 10 times every 24 hours. Then always maintain 100% voting power.