If you,ve done nothing to the system and it was working.
Battery voltage OK.
Voltage at the outlet OK.
Blocked non return valve.
Blocked filter.
Kinked pipe.
Blocked tap valve
Blocked tap nozzle mesh (if fitted).
Good Morning. If it is working on EHU, but not working on battery only, then the culprit seems to be the battery. Check the voltage on the battery and battery connections. Good luck.