4sevens Quark AA2 R5 current draw

[AnAppleSnail]

The Quark goes into buck mode. Add this to your table:

Watts
1.77W
2.63W
3.41W

The short version is that all drivers take V1*I1=W1 in, and output V2*I2=W2, where W1 and W2 are related by an efficiency (Usually 85-95%). A boost driver takes high current and low voltage to output low current and high voltage. A buck driver takes low current and high voltage to produce high current and low voltage.

 

[troelskc]

The Quark goes into buck mode. Add this to your table:

Watts
1.77W
2.63W
3.41W

The short version is that all drivers take V1*I1=W1 in, and output V2*I2=W2, where W1 and W2 are related by an efficiency (Usually 85-95%). A boost driver takes high current and low voltage to output low current and high voltage. A buck driver takes low current and high voltage to produce high current and low voltage.

How about this then:
Emitter Vf Bin U range I stated U (V) I (A) I eff. P con P effective. I to emitter (A)
XM-L 3,1 T6 3C 3,4-12 2,5 4,2 0,75 0,71 3,2 3,0 1,0
XM-L 3,1 T6 3C 3,4-12 2,5 8,34 1,5 1,43 12,5 11,9 3,8

This looks right? But why does the current at the second example go up to 12,5 Watts @ emitter when running 2 * 18650's??? It should only be around 2.5Amps as stated by manufacturer.
Either the buck driver is VERY inefficient and then delivering the 2.5A to the emitter OR the emitter gets 3.8Amps!!!

Another example. The Lumens Factory XP-G HCRI 90 I just got, the manufacturer mailed me this:
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At a single 18650 it will deliver about 0.75A to the LED.[/FONT]

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[/FONT]The full (1A) output of your D26-LED should be reached at 4.8V such as a 2 x CR123a application or higher voltage.

The optimum input voltage is 4.8V to 9V.

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[FONT=&quot]

[/FONT]Our driver is very efficent and do not draw that much current from the batteries.

It gives an input of 1A to the LED, but do not draw 1A from the batteries.

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What are this all about? Are there drivers which deviates from the 85% / 95% efficiency?

 

[AnAppleSnail]

How about this then:
Emitter Vf Bin U range I stated U (V) I (A) I eff. P con P effective. I to emitter (A)
XM-L 3,1 T6 3C 3,4-12 2,5 4,2 0,75 0,71 3,2 3,0 1,0
XM-L 3,1 T6 3C 3,4-12 2,5 8,34 1,5 1,43 12,5 11,9 3,8

I am having a LOT of trouble reading this as a chart. What are your column headers are (U range, Range I, I stated, Stated U, Stated U (V)? Which of these are your columns?). Which numbers are stated as a range, or as two separate values? What the independent variable is meant to be. Which light is this? Are these your measurements? How were they taken? Why isn't the voltage of two cells twice that of one cell? Why do you calculate 95% efficiencies twice? I will guess that this is your intent (Ignoring bin (T6), tint (3C), and input voltage):

LED	Stated current (By whom?)	Battery Voltage	Measured current?	95% of previous column (Why?)	Watts	94% of previous column	Amps at emitter (W/Vf)
XM-L	2.5	4.2	0.75	0.71	3.2	3	1
XM-L	2.5	8.4	1.5	1.43	12.5	11.9	3.8

Many flashlights with buck regulators go into an overdrive mode. I'm unaware of a FourSevens flashlight that meets your description (XM-L, 2x18650, 2.5A stated current). This often displays as a massive increase in output as seen above. The minimum efficiency for a Li-Ion light is very nearly (#cells)/(#LEDs in series). So a two-cell flashlight's minimum likely efficiency is around 50%. You would have to try to get lower than that

What are this all about? Are there drivers which deviates from the 85% / 95% efficiency?

Yes. I gave a rule of thumb, but do not manufacture driver circuits.

 

[troelskc]

Sorry 'bout the messy chart. It did look nice in the preview. I've answered your questions IN the quote:

I am having a LOT of trouble reading this as a chart. What are your column headers are (U range, Range I, I stated, Stated U, Stated U (V)? Which of these are your columns?). Which numbers are stated as a range, or as two separate values? What the independent variable is meant to be. Which light is this? Are these your measurements? How were they taken? Why isn't the voltage of two cells twice that of one cell? Why do you calculate 95% efficiencies twice? I will guess that this is your intent (Ignoring bin (T6), tint (3C), and input voltage):
Comma = dot (, = .) It's european style
Dash (-) are a range.
Voltage is the exact measured before the test.
Stated current = Manufacturer stated.
I did ignore the bin and tint in the calculations.

LED	Stated current (By whom?) Manufacturer	Battery Voltage	Measured current? At tailcap		Watts	94% of previous column	Amps at emitter (W/Vf)
XM-L	2.5	4.2	0.75		3.2	3	1
XM-L	2.5	8.4	1.5		12.5	11.9	3.8

Many flashlights with buck regulators go into an overdrive mode. I'm unaware of a FourSevens flashlight that meets your description (XM-L, 2x18650, 2.5A stated current). It's posing as an example using a Dereelight DBS V3. This often displays as a massive increase in output as seen above. The minimum efficiency for a Li-Ion light is very nearly (#cells)/(#LEDs in series). So a two-cell flashlight's minimum likely efficiency is around 50%. You would have to try to get lower than that I'm not sure what you means by the 2 last sentences about the 50% efficiency.



Yes. I gave a rule of thumb, but do not manufacture driver circuits.

Thanks for your time!