Battery keeps losing charger

Hi. I have tried many ways to keep my TomTom One XL fully charged. But, if it is not plugged in it's loses charger - sometimes overnight. We do not have the same problem with the One, Just the XL. I have tried holding the power switch until it completely closes down - but this doesn't work either. It is so frustrating when you want to check a route - but can't as it won't power up - you need to charge it for a few minutes first. Can anyone give me any advise on this? I have searched and searched lots of forums and the best advise I have found it that you should power it down completely (which I have done) otherwise it will still be on standby using power.

[getsurfers]

Are you leaving fully charged, yet only using rarely?

This is a killer on batteries.

I have discovered that my tomtom one switches itself on at exactly 3.20pm every Saturday
thinking that it was getting some sort of signal from within my house,I put inside of a heavy steel safe
It still switched on at 3.20
I assume it is something inside of tomtom doing this
I suggest watching yours closely to see if yours does it at same time every week