How to use a Epistar Cree XHP70-Replacement LED?

Hello,

I have been looking for a bright LED with a small diameter and found the Cree XHP70 that seemed to fit alright. Because of the high price I tried out a cheaper replacement that uses "x55mil Epistar" cores. I put the technical data from the chinese seller in a picture together with a photo of the module. The blue symbols (+, - and C) were added by me, because they were not on the original image but on the real LED-module.

My problem is, that I expected the LED to draw about 18W when connected to my laboratory power supply (which can provide up to 3A), but it only draws about 3 W (0.5 A, 6V). I know that it is unusual to use such a power supply, but it should work nonetheless, should it not?

At first I was not sure how to connect it to the power source, because on some Cree XHP70-modules you can use either 6 or 12 V, depending on which pads of the board are connected. In my case it does not seem to make a difference if I power both + and - -Pads or just one of each. Also I have no idea, what the "C" means, the original XHP70 boards I looked at before only have "-" and "+" pads.?

Would it be possible to safely increase the voltage until 18 W are reached if I only want to flash the LED for less than a second each time?

Datasheet

Like many 4 core LEDs the LEDs are configured in series / series-parallel.

Each LED takes about 3V so a pair in series (a chain) takes 6V; Wired 2 chains in series thats 12V (1.5A), or in parallel 6V (3A)

IF they are series / series they would need over 9V before you got much current flow.

If you are powering only 1 chain it should take 6V 1.5A

Does the board have a chip on the reverse? (as used in flashlights to handle battery voltage)?

Also be aware you need a heat sink to keep it cool.