Battery measure (4)
I believe the answer is:
volt
'battery measure' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for volt that I've seen before include "A measure of electricity" , "little force" , "Electrical SI unit named after a pioneering Italian physicist, d. 1827" , "Electricity unit" , "Unit of electric force" .)