Try checking your transformer primary inductance and output winding polarity. The transformer core must have an air gap in order to store the proper amount of energy per cycle without saturating. Also, the windings must be configured such that the anode of D3 goes negative when the primary switching fet in U2 is on.

The circuit as shown is only capable of CV output. Additional circuitry will be needed for CVCC functionality.

Sir, I have getting 9Amp now by replacing C4 which was faulty. It is working fine with Resistive load like DC BULB.
But when connected to battery it restarts / no charging.
The Transformer data is in attachment.

Should you guide me the additional circuit for 15.3V / 10A CVCC SMPS (Purpose Lead Acid Battery Charging)

Thanks

You will need a circuit similar to that in this reference design:

https://ac-dc.power.com/design-support/reference-designs/design-examples/der-583-106-w-high-line-input-non-pfc-cv-cc-flyback-charger-supply/

Sir, Can I change my circuit to CC mode with some minor modifications. It will be ok for me without CV mode

You will need CV mode as well so that the power supply does not lose its mind when unloaded.