Triple XPG R5 plus XPE R3

[brad72]

Hi ,

I have got the triple XPG R5 but as all of us are finding the available triple optics to not give a very good throw, are wider and the 1C tint is very white making it hard to see well in the bush compared to lets say a WH tint XPE (very warm)

1 solution I am looking at is making a housing with a Triple xpg with the a frosted medium and a single XPE WH tint with either a 20mm 7.5 or 13º spot optic to give throw and add some yellow to the XPG for better visibility.

My question is, running off a 3021 1000mA buckpuck, can I run the leds in 3s1p. 3s being the Triple xpg and 1p being the xpe or am i better to use another driver to power the xpe separately. I don't want to go up a battery size (currently 14.8v) which is why I don't want to wire all 4 leds in series.

Thanks

 

[brad72]

I've found a simple solution in using a buckpuck without dimming and therefore doesn't need a battery with 5 volts more than the combined forward voltage of the leds, therefore i can run all 4 leds in series and run them from a 14.8v pack.

 

[znomit]

I've found a simple solution in using a buckpuck without dimming and therefore doesn't need a battery with 5 volts more than the combined forward voltage of the leds, therefore i can run all 4 leds in series and run them from a 14.8v pack.

The buckpuck overhead is quoted as 2V, though I think its less than that(closer to 1V).
Not sure if you'll have enough battery for 4 leds.

This is separate from the 5V reference, so you will have dimming capability still.

 

[brad72]

changed maths due to brain explosion- Thanks Vaska

Thanks for that, missed the 2 volt overhead. I know the xpg's at 1000mA draw around 3.2v and an xpe around 3.4 plus the 2 volt buckpuck overhead=15.1v . A fully charged 4s lipo is 16.8v so yes, I will be running too close to the line. Perhaps my 5s lipo's will be the way to go after all and run the leds in series off the 1 driver

Not a big drama as the lights only weigh about 130grams.

 

[vaska]

Thanks for that, missed the 2 volt overhead. I know the xpg's at 1000mA draw around 3.2v and an xpe around 3.5=15.8v.

Tree XP-G plus one XP-E at 1 A makes 13.1 V. The best solution, IMHO, is to use linear current regulator with low-resistance power FET. Throughout the range from 16.8 V (full-charge) to 13.1 V (LED voltage drop) you'll have efficacy better, than 90%. And from 13.1 V to 12 V (recommended discharge) you'll watch progressive dimming, that will mean oncoming battery discharge protection cirquit activation.

 

[brad72]

I have another buckpuck and some more leds arriving from cutter tomorrow so i'll have to do some experimenting. Good job I have some many different lipo battery packs lying around.

I do like the idea of building a linear current regulator though as the overhead would only be a fraction of a volt and great efficiency. Have to get some components and give it a whirl, just need to find a suitable schematic and make a board.

 

[vaska]

I do like the idea of building a linear current regulator though as the overhead would only be a fraction of a volt and great efficiency. Have to get some components and give it a whirl, just need to find a suitable schematic and make a board.

You can find an approved schematic here, just redesign it for higher tension.
Though the forum is in Russian, the cirquit won't be a puzzle