Thanks for the replys , its a great little camera for sure. There are some older models where the button cell can be replaced , i have found nothing on a diagram for this camera .
Maybe it is my AA batts losing capacity. They are about 5 years old now.
I will defo look into the remote PSU supply though.
I have found nothing about changing the battery that holds the settings like time and date other than a reference to an internal rechargeable lithium battery
https://support.usa.canon.com/kb/index?page=content&id=ART121461.
You are getting the red icon on screen flashing indicating low battery - right? You are using rechargeables that are 5 years old? Yeah pop some new batteries in there and you may be good to go. If you have to keep setting time and date maybe you have other problems but until you try it with fresh, fully charged cells, you will not know.
As for not having to buy a dedicated PS, I never said that you needed to buy a dedicated PS - in fact, what I said was "buy or make". Since they (used?) to sell a NiMH charger and cells for that cam and also say it is ok to use non-rechargeable batteries, obviously there is a voltage range there - nominally 4.8-5.0V. That their PS is rated at 4.3V out is notable. What is more important, IMO, is that it is also rated at 1.5A, which seems a bit hefty for a camera that operates on 4 AAs. At least in my view.
If you look around you can still see posts with lots of dissatisfaction with the number of pictures you can take on a set of AAs and that is why - that camera sucks up a lot juice. For road trip work, I always used to carry a spare set of batteries. The PS, which did not cost much if I recall, is very nice for any kind of bench top or copy stand type work. It has an extra long cord (two actually).
Hope it helps.