Mathmos bubble question ...

[chris]

Hi people,

Yep I realise the bubble isn't lava but being Mathmos hope for some help here. Have a few bubbles and around 7 yr old - just tried them and all 3 are much brighter plugged into the charger than running on internal battery. Never noticed any difference before now.

Question is, has anyone noticed the same and if so, anyone taken the plunge and attempted to slice open the silicone to replace the battery ?

Thanks people.