I am planning to use an old mobile phone charger. its output is DC 5 V @ 800 mA. The LEDs I'll be using are 1-watt high intensity diodes with a forward voltage of 4.1 volts @ 250 mA.

I want to connect 3 LEDs in parallel so their combined amperage will be 750 mA which is quite close to the rating of the charger.

will i need anything else (like a current limiting resistor or something else) in the circuit?

I will install the LEDs on an aluminium heat sink wrapped around an old CFL screw-type base. I have the physical installation plan in mind. I just want to ask about the electrical aspect of this LED circuit.