P7 and 18560 - what is max current?

[Sponge]

I have P7 lamp bought from dx. Whena I connect emitter directly to cell (4.2V at open circuit), current is 1,2A and voltage drop to 3.8V. Is this normal and can P7 work at full current at one cell (2.8A)?

 

[baterija]

Sounds like it's a pretty high Vf emitter, although a high resistance somewhere else in the current path could have some effect. A P7 can be driven at or above the max rated current from 1 18650. The Vf is the biggest influencer of what the current will be. Was there any indication of the Vf bin on the LED you bought?

 

[Sponge]

Sounds like it's a pretty high Vf emitter, although a high resistance somewhere else in the current path could have some effect.

I have place + of cell on + of emitter, and - of cell on one lead of multimeter other lead of multimeter on - of emitter. multimeter was on 10A shunt.

A P7 can be driven at or above the max rated current from 1 18650. The Vf is the biggest influencer of what the current will be. Was there any indication of the Vf bin on the LED you bought?

http://www.candlepowerforums.com/vb/showthread.php?t=227147
this is thread which describe this light. I suspect that P7 in it is some "defective" bin which is very cheap, since lamp is not genuine and made by unknown manufacturer. So, I have measured current and is not as expected or as current/voltage characteristic in P7 datasheet.
BTW, baterija, where are you came from?