I have my lights on during the day. They sleep when I do. this avoids paranoia over the helicopter as they can only pick up unusual heat sources at night. Or more specifically, after midnight.
You're ok though if you're only running like say a 1000watts. In fact, a residential home should be ok for 2000w during the night. Any more and you're risking your home being earmarked.
They can't do anything, well not in my country, as they are only looking for the larger scale operations, with 10's of thousands worth of wattage. The next thing they do is figure out where they're getting their electricity, as they have to be stealing it. This is how they get their warrant.
Even if your place has been earmarked there is nothing they can do unless you give them some kind of IN.