Mongoose Traveller combat armor: TL 11 is 18kg, TL 12 is 10 kg, TL 14 is 6 kg
Mongoose Traveller battledress: TL 13 is 26 kg (6.5 kg when powered up), TL 14 is 12 kg (3 kg when powered up).
Traveller 20 has the same weights for combat armor as Mongoose Traveller. T20 battledress isn't personal armor - its treated as a vehicle, so is rated in volume liters. Battledress is 300 volume liters, while the typical ground car is 2000 volume liters. There is no conversion listed to determine weight from volume liters for vehicles.
The core rulebook for TNE has TL 10 combat armor at 13.3 kg, TL 12 at 20.4 kg, and TL 14 at 18 kg. It also has TL 10 battledress at 419 kg, TL 12 at 197 kg, and TL 14 at 296 kg.
The MegaTraveller Imperial Encyclopedia has TL 11 combat armor at 18kg, TL 12 as 10kg, and TL 14 as 6kg. TL 13 battledress is 26 kg, and TL 14 is 12 kg.
It seems there are two interpretations of battle dress. One, used by Mongoose Traveller and Megatraveller, has battledress as powered combat armor. So weights should roughly be similar (though battledress should be heavier then combat armor). The other interpretation, used by Traveller 20 and The New Era, have battledress being much larger then that.
With the exception of TNE, the weights of combat armor are consistent in the versions of Traveller I have access to.
TL 11 combat armor is 18kg
TL 12 combat armor is 10kg
TL 14 combat armor is 6kg