I have a 600mm x 600mm LED panel with 576pcs 3014-type SMD LEDs in some unknown configuration/topology (edge-lit, similar to this one here: http://i01.i.aliimg.com/wsphoto/v0/1990066259_5/Wholesale-3PCS-Lot-48W-Led-Panel-Lights-60x60cm-Led-Panel-600-600mm-Ceiling-Panel-lights-LED.jpg ). I thought the standard way to power it would be a constant current driver, like the one I use for my smaller COB lights. I tried a 300mA driver, which resulted in 34V voltage drop (for the whole panel). The panel was fairly dim and clearly needs more power, but I don't know how much, as I have no data sheet of the panel or the individual LEDs.
How do I find out how best to power this panel without damaging it?
One idea was to try varying the current in a friend's lab (with his adjustable power supply), but where to stop? Is there perhaps a voltage limit over a single (white) LED that I could watch out for? Or is there some other useful measurement I could make with a standard multimeter?
I am looking for a method that does not involve a soldering iron because I do not have one suitable for SMD to re-assemble the LEDs.
(This question is related to Easy way to figure out a LED's Vf in order to pick an appropriate resistor but not quite the same, so I have opened a new question.)