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I’ve also considered XHP35 HD CRI80 http://www.kaidomain.com/p/S026064.Cree-XHP35-HD-D4-50E-White-5000K-LED-Emitter

The Led Lenser V2 TL has a TIR (spot) optic. Maybe the xhp35 would be better suited? Heat and current for xhp50.2 could be a concern, (one reason I like your set up with the temperature sensor in the led board) although it’s a very solid built light, thick walled and tight fitting threads

I see he driver also works with XHP35 but are the voltage difference is too great? (12V-8.4V)

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XHP35 is 12V led, which type and how many cells you plan to use in that light?

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I’m using 2*26650, 8.4V

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Then it isn’t possible to use a xhp35 with this driver.
You’ll need a boost driver for that.
You can use the xhp50.2/70.2 in 6V configuration.

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4*26350 then choose 4S option for the driver.

Btw, is that even a mechanical switch? It looks like it could be an electronic switch and if that’s the case you need to find another driver anyways.

Also, if this is a 3xC cell light and you are trying to make it a 2x 26650 I dont think you should just be using longer springs to take up the room. You should either make or buy a “dummy cell” (a 0 voltage spacer)

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3xC you could possibly do 4x26500’s for the XHP35…

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Thanks everyone. Ok just so I understand, the driver is not boost or buck it does not change the voltage, and it’s okay to run the 6V led at 8.4V with the 2S cell config, and since 4S was suggested I assume it’s okay to run the 12V emitter at 16.8V? Are there limits for powering emitters at higher voltages than their listed/rated voltage?

  • Switch: I believe it’s a mechanical switch. You cannot do momentary presses until after the switch has been fully clicked ON, like a reverse clicky. (it’s currently single mode so after 1 full click to ON the half presses just blink the led) From my understanding of them a momentary e-switch doesn’t “click” or “latch” to ON.
  • longer spring: The longer spring isn’t for the battery length, for the battery compartment spacing (about 12-14mm) I plan to make a short dummy cell type spacer. The longer spring is for the distance between the bottom of the driver and the top of the switch, which has a center contact. The switch sits between batt+ and driver+ and occupies/seals off the forward part of the tube (like a Maglite)
  • Cell configuration: It will also fit 3x26500 for 12.6V, however 26500 seems to be nearly non-existent, MTN has some but I’m not sure what currents they can provide as they don’t list the spec. there but they may work. I’ll need to look into the 4*26350 idea and consider the costs to go that route.
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Do you have an eta on when an e-switch driver will be available?

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@vinte I'm currently busy with other stuff, so I can't tell eta.

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LD-B4HV is linear, so that means input v = output v, correct?

For my options:

  • 2S / 8.4v input = 8.4v output to led
  • 3S / 12.6v input = 12.6v output to led
  • 4S / 16.8v input = 16.8v output to led
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That correct. The driver can convert some voltage down, like 8.4V at the batteries -> 6V at the LED, but burns the excess voltage away as heat in the FET, which is also the reason the FET is placed on the ledboard.

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Also 3S is going to sag below 12v instantly when load is applied so dont use that for a 12v LED

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LD-x4(HV) is linear constant current driver, linear means driver regulates output current by burning excess voltage into heat (via electronically variable resistor,which is mosfet in this case),so its output voltage can't be higher than input voltage; constant current means output is current regulated, driver doesn't care what output voltage would be, as long as LED voltage is lower than battery voltage, output current will be constant.

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Did you mean 4x26350? A 26500 is basically the same length as a C cell (about 50mm incl. button)

I have about 150mm battery space.

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Thanks everyone for the helpful info.

So in my case, from what I’ve just learned, XHP35 is not a viable option with this driver.

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Plenty of people have made hot rod type lights with 4x26350 but if you really want to use XHP35 you may be best served to wait for a good boost driver so you have more battery options. (or go with one of the existing mediocre boost drivers that are out there)

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No I meant 4x26500’s, for some reason I thought C’s were the same length as D’s cells just smaller diameter? I have several lights that run 3 cells (18650/32650) and now they run 4x26500’s and 4x18500 with the XHP35HI/HD’s in them, that’s why I stated possibly I wasn’t too sure of it. :slight_smile:

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I understand it would work, but I don’t think I’d be happy dealing with 4 cells for only 2000mAh.
But maybe xhp35 is more efficient to run than xhp50.2? Or does the drivers output current rating determine efficiency?

Not sure I’d consider this a “Hot Rod” by today’s standards, but I suppose it could be.

I could get the MTN-MAXlp HP, but this LD-x4(HV) seems to have much more going for it, almost like a “Dream Driver” ?

.
Sorry if it’s been mentioned already but does the mosfet create additional heat at the mcpcb?

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Ok I see, thanks, ya D cell is about 61mm so about 11mm taller than C.

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So now I am back to the original plan of using XHP50.2

I need to decide on which current range to get.

Output current - (wattage)

  • 2-3A (12-18W)
  • 4-6A (24-36W)
  • 7-9A (42-54W)

Are these estimates correct for wattage at the LED? (assuming 8.4v input will reduce to 6v output)

Also I assume the cells must be capable of supplying even higher input currents to enable these output currents?

Cree specs show 3A/18W Max. (I know it can be overdriven though)

.
I’m leaning towards 4-6A, any suggestions?

Considerations:

  • Higher wattage = increase lumen output = more heat
  • 1. Body is full sized, tube/neck is very thick (about 5mm) Head is thinner, and no cooling fins.
  • 2. Unsure of power handling capability for the switch.
  • 3. 50W @ LED could melt the TIR optic?

Also, how to run the 3 additional leads through the pill (16mm mcpcb space)

I assume I’d simply enlarge the existing holes? It looks like the mcpcb’s cutouts are wider than usual for this: