Driver for QUAD XP-L Hi

May I ask why you must use 5S battery?
20V Power tool pack?

Quad XP-L HI builds usually use the 4 LEDs in parallel and can be run off a single high discharge 18650. 5P cell would get you 15,000mAh at 80-100 Amps if wiring is done well. Quad XP-L HI in parallel can suck over 15A!

I’m thinking the clue to the reason for 5S cells is in the facebook link on OP’s signature. It says …tecdivelight… as part of the link.

But, if the OP can at least get it down to 4S cells, then the 4S LEDs can be driven from a linear or FET driver. As it is, the requested set-up will require a buck most likely. We haven’t got nearly as many good choices in buck and/or boost drivers.

Missed that, thanks David.
checked it out, looks pretty cool but didn’t read in depth.
Yeah a LiIon dummy cell would easily do it. Even if LiPo, 4S are common in variety of sizes.

I do not want to use parallel leds because of the possibility of thermal runaway.
I would prefer buck drivers with a 5s battery pack. Because if I use a 4s pack for 4 serial connected leds and a linear/dd driver as the battery discharged the light’s output will also decrease. I would like to have constant output. And I need it for at least 2-3 hours.
The LVP is 2,85V/cell. —> 4s battery 4*2,85=11,4V, 5s battery 5*2,85=14,25. So the voltage of a discharged 5s pack is still higher than the forward voltage of 4 leds (4*3=12V).

So, buck driver is preferred, but if there is no way to find a reliable driver I had to get down to 4s.

What linear/FET driver would you recommend?

Another possibility: Why not use XP-L2 HD emitters instead? Sure, you’ll lose a bit of throw, but probably not enough to be noticeable. The XP-L2 HD has lower Vf and much higher lumens output than the XP-L HI. So, even with 4S cells, you’d stay in regulation for a lot longer. You could even dial back the current, to make the light output match what you’d be getting with the HI’s and that would increase your runtime even more. Overall, it’d be a HUGE gain in runtime, compared to a small (maybe not noticeable) loss in throw.

The only buck solution I know of for 5S would be a 5S Li-Po, for 18v max charge, and then you could use a Texas Buck (designed by Texas_Ace, but AFAIK, not yet tested) or a MTN-MAX from Richard at Mountain Electronics.

That would be a good idea.
The only problem that there is no small spot reflector available for XP-L2.

A reflector works with both, just for same throw you need a bigger one
Or slice the dome of the XPL2

Okay, here’s another unsolicited somewhat silly idea. :stuck_out_tongue:

But, it would work. :wink:

You could use your 5S Li-Ion pack to feed a Quad XP-L HI with one of these either inserted before the driver, in which case a FET or linear driver would work, or instead of a driver, if you don’t need any modes but on/off. It’s simple and cheap.

Biggest issue is that you lose some capacity (run time) due to needing 2V overhead to operate. But, if you wanted, you could add more cells in series to make up for it. With an input range up to 40V, you could go as high as 9S Li-Ion.

Another (possible) issue is that it only puts out 2A current. I don’t know how hard you were wanting to push those XP-L HI LEDs, but at 2A drive, 4x XP-L HI V3 would give you around 3200 lumens.

Unfortunately it is too big and I also need modes.
And 3x XP-L Hi can also produce 3200lm.

One question I have not seen asked is are you limited to 4 chips? Since you seem to want to use the 5s pack, why not 5 chips in series instead of 4? Not sure of what kind of footprint you want etc, but there are plenty of SRK style lights you could turn into a decent light.

One other quick ? Are you using round cells or are you using lithium polymer “bag batteries” used in the RC world etc?

I would like to use 4 leds with 5 cells because I would like to have constant output and to avoid the buck driver to go out regulation.
I do not use RC lipo batteries, cylindrical li-ions are better for my project.

Thank you.
I have contacted this ebay seller and he said that these drivers are too weak for 5s and 4 LEDs.

Biggest one can carry up to 30W output. Input voltage doesnt matter.
Anyway, they are times more reliable than LM-based boards showed by DavidEF.

I was interested in LDR23 and LDR29.
But according to the designer/seller they are too weak for my application.
They can not run continuously 4 leds because they get too hot quickly.

Check Product Comparison
I used his drivers for diving lights.

b3Flex is similar to h6Flex different max current

H6CC does not have microcontroller which may be a good thing depending what you want.
Microcontroller drivers (b3Flex and h6Flex) have PWM at low current (I think below 0.5A) for efficiency, if you will use light for video you will see flickering.
If you want just one level I would use H6CC, you could do couple of levels using resistors instead of pot but switch may be tricky to find/make.

Flex drivers will work with momentary switch including piezo but it must be “prolonged piezo” which means that when you hold it, it gives longer impulse.

I know these drivers.
I also used piezotg from this seller but I’m not satisfied with the quality so I decided to ask an electrical engineer to develop me an own piezo latch circuit.
So I would avoid the drivers also.

I still have not found any solution for the 5s driver so I started thinking about a serial-parallel connection of leds.
My idea is to use a 3s2p battery and a 2s2p led configuration.
I have heard that it only could work with specially selected and paired (identical) leds.
Does anybody have experiences with it?

Have you looked at this driver?

http://www.taskled.com/h6flex.shtml

I am building BLF driver design that can handle up to 6S with a 28V LDO I have to order over the 18V I have now

Output is tested 5A so far but with upgraded parts I build today more that should reach 8A without any problems well in specification

price 22$ 5A
24$ up to 8A

ATM 42 and 47.5mm size availiable, 30mm planned