How much current to LED with 4x123 cells

[jaybiz32]

How much current would a q5 Led see if run with 4 123 primary li-ion cells direct drive?

 

[TigerhawkT3]

Past a fraction of a second, none, because it would .

Also, Li-Ion is not primary, it's rechargeable. Ordinary lithiums are primaries.

 

[jaybiz32]

What is the formula to figure out current to the led based on direct drive?

 

[TigerhawkT3]

http://www.cree.com/products/pdf/XLamp7090XR-E.pdf

Page 7.

 

[Gunner12]

It also depends on the individual LED. In extreme cases(Using the Cree XR-E Q5 as an example), the Q5 will only be drawing 700 mA at 4v but a normal Q5 at 4v will be drawing well over 2 amp.

A driver also isn't that expensive.