Well! It's a coincidence. Out for the sunrise in around -2c with camera in bag (was at room temp from home).
I saw a nice scene, took the Dynax 5 from its bag and composed and ... the camera said NO. Battery flat. This camera seems to "see" the battery voltage as being low most of the time.
I was ready for it... changed the batteries for new CR2 cells. Still battery flat. So I couldn't use my film cam (the day was not lost, used my dig cam).
Back home, tried both sets of batteries in the spare Dynax 5 which was quite cool, around 10c. Same indication. Same batteries (old used set and new set) in Dynax 404si (from same, cool place as the spare Dynax 5) and it was fine, seeing both battery sets as full capacity.
I have read that the 5 can be heavy on batteries, perhaps that is because it measures them as too low.
So the Dynax 5 might make a summer cam for me, but I will replace it with the 404si or a 505si super when chance allows a purchase.