I don't know if it's changed recently. The number is 27.8 times per day, if you vote every 3100 seconds (a little more than 51 minutes). You can calculate this by plugging 100 into p and p+ in my 2nd equation and solving for T. Due to an error in my formula (which I'll correct when I get a chance), you'll have to divide your answer by 100.

But here's the thing: the 27 number is only if you want each of your votes to be at 100% every single time. It just doesn't hurt you very much to be voting at 90% or even 80%.

The fact that you lose voting power for voting is not a penalty, it's just a simple mechanism that limits each account's total influence. If I had to give a simple message to you, it's that you just shouldn't worry too mich about optimizing your voting power, because the only bad choice is to vote too little.