KOOL, problem sorted. :clap:

Do you turn off the apps as well?

As well as the size of the battery in a phone the device is intermittently talking to any cell tower it can to report it's location so any incoming texts or calls can be routed to it. Your tablet only has to do this if it is turned on and a particular app needs it (and it has to be a 3G tablet).

So even in standby mode a phone is having to use battery to communicate to the phone network, compared to a tablet which does nothing in standby.