Not sure why it took me so long to realize it, but for two years since receiving an Apple Pencil for Christmas, my iPad battery life sucked. Anyway, fast forward, I finally did think to myself, you know what, this shitty battery life seems like it started right after beginning to attach the Pencil every day.
Here’s the battery life, with pencil attached, and with it not attached. This is on an iPad Pro 11 with Pencil 2. You’ll see that with almost zero screen on, it went from ~75% to 57% in fifteen hours or so. Then, with it not attached, it went from 100% to 98% in just over nine hours. It loses more than a percent per hour with the Pencil attached.