Let me put it this way - with minimal activity, the Acer A100 would lose 3-5% a night on standby; the Kobo Vox about the same, and the Galaxy Tab Plus would go down 1-2% overnight.
And then you've got threads like
this one that show standby drains of 1% per hour. I'm wondering what services, besides the screen, are running the tablet's WiFi or GPS to cause issues. That's not normal for tablets with a decent OS (Gingerbread was awful) and battery (above 2500 mAH), not given the variety I've used.