[owent]

Some info please on this triple xpg the Vf is 9V so what is the maximum that can be used as it does not state it in the tech info i am planing to use 18650 batteries so 3 in series is 11.1V this would be ok?

http://ledsupply.com/creexpg-w417.php

 

[MrLee]

What no driver?

 

[owent]

yes b2flex all part of my new headlight build previous version was lux rc 312 xpg @350l
but wanted some more light so trying out this triple

 

[klynk]

3*18650 (freshly charged) are 12,6 V

 

[MrLee]

How hard are you driving them? forward voltage is about 3.5V @ 1500mA?

That gives you about 10.5V, plus the head room for the b2flex - 1 volt?

 

[owent]

Not to sure of the configuration so far still new to the b2flex driver first time using one but will set it up to one of the pre progamed settings something like 350,700,1000,1200ma
this is a head lamp for walking so i have to be careful not to drive it to hard as air movement is limited at walking pace.
still learning so never took into account the 1v needed for driver as well ? so then what would be optimal battery configuration then?

 

[Vancbiker]

Optimal would be 14.4V. That will stay in regulation for the entire runtime. Using an 11.1V will work as long as you don't mind going out of regulation near the end of the runtime and a slight dimming as a result.

 

[emu26]

How hard are you driving them? forward voltage is about 3.5V @ 1500mA?

That gives you about 10.5V, plus the head room for the b2flex - 1 volt?

No, 1 volt was good for the bflex but the b2flex wants more. From the manual (see George I do read )

The following table illustrates the minimum voltage difference versus current for 1 LED and 2 LEDs
(or more) to ensure the driver remains in current regulation.
Number of LEDs (typ Vf 3.4V) Current Voltage input (Min)
1 350mA Vf + 0.8V
1 500mA Vf + 1.1V
2+ 500mA ΣVfn + 1.2V
2+ 750mA ΣVfn + 1.3V
2+ 1000mA ΣVfn + 1.5V
2+ 1200mA ΣVfn + 1.6V
2+ 1500mA ΣVfn + 1.7V

 

[equalme]

I can see a difference in light output between 7.4V ([email protected]%) and 11.1V ([email protected]%) on my dual XPG with b2flex @ 1.5A.

 

[owent]

Thanks for the help i will make up a 14v pack