Same laptop here. I've noticed the laptop drains battery when its suspended which is pretty annoying because I sometimes go a couple of days without using it. Have you run into that? I haven't had any luck getting suspend to disk to work.
It does drain, maybe 2%/hr but I thought that was normal? That's what I expect to get on a Mac. I did have to `echo XHC > /proc/acpi/wakeup` because I would shut the lid, but something on the USB bus kept turning it back on.