A bit depleted, get a top-up at the station (5)
I believe the answer is:
depot
'the station' is the definition.
(depot is a kind of station)
'a bit depleted get a top-up' is the wordplay.
'a bit' indicates taking the first letters (I've seen 'bit of' mean this).
'get' says to put letters next to each other.
'a top' becomes 'tope' (I can't explain this - if you can you should believe this answer much more).
'up' shows that the letters should be reversed in order (in down clue: letters go upwards).
The first letter of 'depleted' is 'd'.
'tope' written backwards gives 'epot'.
'd'+'epot'='DEPOT'
'at' is the link.
Can you help me to learn more?
(Other definitions for depot that I've seen before include "Bus station or warehouse" , "Supply base" , "Storage base" , "storeroom" , "Military HQ" .)