The reason it drains off so fast is that after hardfork (2 days ago) every full-power upvoted consumes 2% of your voting power. Before hard fork it used to take only 0.5% per vote. So currently your power is droping 4 times faster. The solution is available though, you can control this by scaling down the voting power level. However this is possible only for those , who got 500+ of steem power on their accounts