Battery rapidly discharging, even more whilst...

Question

Hi.

As you can tell by the title I am having problems with my Z310i it seams to be discharging the battery rather rapidly.
Considering that the battery is the weakest spot of most portable items I invested in a replacement battery but to no avail.

The odd thing is that the rate of discharge seams to increase when the phone is turned off and it also has the habit of vibrating whilst in the off position.
I have a funny feeling that on or off one feature of the phone is to vibrate to allow the user to acknowledge that the phone is in need to be re charged, not to sure if this is entirely correct thou.

Any one got any ideas on this one I would be rather sad to see it go as it is a well featured phone and not only that a it was present to my wife?

Regards

Andy P