It can be confusing. If you upvote something with 100% vote... it takes 2% of your voting power. I can't remember how fast it recharges... like 1% every hour i think. So, generally you get about 10 upvotes to give out at 100% per day if you want it to recharge back up all the way. It's not proportional to your stake as far as recharging goes. 

However, the more you have powered up the bigger your vote is and the more you can split it into smaller portions to spread around. I think commenting is a great way to give back by sharing your opinions and engaging on other people's posts aside from upvoting. When you vote on posts... some of the rewards come back to you. 

When you vote on comments, there is no curation reward to come back to you for that. So, keep that in mind. It used to be that a comment needed at least 2 cents to payout to the person. Otherwise, it was a waste of upvoting power. But, i don't know if that changed or not.