Hi,
I'm using 2 cr2's in a Copper. I vape all day long. It is a battery hog, or I am a vaping hog. LOL
Depends on the batteries. I'm waiting on chargers to come in.
Using the photo batteries from walmart, that cost almost 10.00 for 2, Cr2s, those last about 3 days.
Using cheap ones I bought online for a dollar each plus shipping, they last about a day.
Using the rechargeable Chinese lithiums, they last about a day or even less right out of the package.
It's going to depend on how much you use it and what batteries you have.
I highly recommend getting rechargeables, I am being eaten alive buying batteries without a charger right now.