Acurite 5 in 1 display behavior

I have a one year old Acurite 5 in 1, dual solar panel weather station happily operating on a 10’ mast above the highest peak of the roof. This is a replacement for a 5 year old unit that failed catastrophically, so I still have the display from the 5 year old system.

I have both the old(er) and new(er) displays connected to the weather station and, up until about a week ago, everything was performing as expected. Now, the older display loses its connection to the station 4 out of 7 nights and during the early hours after sunrise (the antenna icon totally disappears) while the new(er) unit never, that I have observed, loses connection. Within 2 hours of sunrise, the old(er) display reconnects then disconnects a couple of times then reconnects and remains connected throughout the day.

The totally baffling part of all of this is that the old(er) display is almost directly below and no more than 16’ from the station while the new(er) display is almost directly below and about 22’ from the station.

I would try swapping locations, but I have both displays semi-permanently installed on recessed receptacles and really don’t want to disturb the mountings.

When both displays are connected, the readings are, as would be hoped, identical.

This is more of an aggravation than anything else, but I figured I’d post and see if anyone has any ideas on the possible (other than the display being older) cause.

Most units have a battery that is charged by the solar panels built inside, sounds like the battery on the older unit has at last failed and the system is only working from the solar panel alone.