Resistor mod for Darth clone driver??

Ok, so what, if anything, could be done with this driver, to get more out of the light. My measurement of 4.2 amps on High, was thru the battery, so I would figure possibly 90% efficiency from the driver, (best case scenario) and that would leave me with 1.25 amps per led.

bsdl

bsdm

I can take more photos of the driver if needed, but any improvement would be good. I can't change the driver, as it's magnetic control circuit means the stock driver has to stay.

Your thoughts on what resistors I could switch would be great. Or, can the High mode become direct drive while maintaining the other regulated modes? I'm sure that sooner or later, this light will either be my personal carry or a giveaway light, depending on how much the amps can be bumped up.

Here's a coupls of better photos.

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Two R010 resistors next to the red wire are current sense resistors. Add another one of those in top and should increase the current by ~30%.

How much it will increase with each added resistor decreases the more of them you have. Just add whatever it takes to get to the desired output.

Guys, all I have right now for resistors thst size are:

One .68 ohm 1/2w

Two .68ohm 1/4w

Two .82ohm 1/4w

and a bunch of 200ohm

What should I buy?

What would happen if I just put jumpers in? Direct drive?, full amps till it fried?

R010s are only 0.01 ohm, so the two of them in parallel are an effective 0.005 ohm total so even your entire inventory of .68/.82 ohm jobbies wouldn't drop the resistance (increase the current) much farther. A jumper would give the max the other components (and/or batteries) are capable of, what that will be, who knows. Is that light parallel cells & parallel LEDs?

Yes, parallel cells and parallel leds.

So, if it's .005 ohm total already, wouldn't that suggest thet it's about max of what the driver would be capable of? That's not much resistance.

Also, might there be a way to redirect the hall switch for the High mode, so it went to DD, but the other ones would still work as advertised?

'Direct drive' by shorting the sense resistors isn't the same as 'direct drive' that completely bypasses the driver circuitry, the modes will still work as normal.

Remember… this thing is a switching regulator. You have to worry about the torrid saturating and the current capability of that big diode. Go too far and it’s friesville…

In a multi-cell buck driver, yes, but not with only 4.2v input.

So, does that all mean, don't try jumpers, or try them?

Or get a few more or the .005 ohm resistors, or better yet, some .001 ohm resistors? Do they make .001 ohm?

If the driver freaks out and goes true direct drive it shouldn't fry the LEDs. The multi-cell drivers are the ones that fry LEDs when you go too far with the sense resistors. 12v into 3v LEDs = dead. This one is only 4.2v input and it's not a boost driver, not much to worry about.

0.01R (R010) at Digi-Key, under $8 for 25: http://www.digikey.com/product-detail/en/RU3216FR010CS/1276-6160-1-ND/3969132

Page with all but the most common values/sizes already filtered out: click You'll have to do some digging to find the cheapest option for each of the values. Some get super-cheap in quantity, some don't, the price for a single piece shown in the big list doesn't mean much.

Sorry if this is a thread de-rail, but the SMD resistors that you guys are referring to in this case are 1206 size. In another thread, Comfy, you suggested ordering the sense resistors that Fasttech sells in a variety pack which are 0805 size, and are physically smaller. I have been looking for a variety pack in the 1206 size and have been unable to find one. They are available in individual values from sources such as digi-key, but are pricey this way, especially with shipping. Looks like O-L might need the same type of variety pack that I do. Anybody have a source for these?

Comfy, I was typing my post and didn’t see your’s until I posted.

Sorry guys, I just found the recent post dedicated to this topic. Been meaning to ask this question for a couple of days, and just saw someone else already did…

I have never seen a variety pack of smd sense resistors. Normal value smd resistors packs I have seen but not the low value sense resistors. If you do find some please post a link. :wink:

I ordered some .001 ohm 1206 resistors from digikey. I will get them tuesday probably, then I can play.

Looking forward to seeing how this works for you, OL. I'd think it'd be safe to simply shunt the resistors. Should make close to DD on high and retain all modes. With parallel cells and only 4.2V input you should be safe. The only thing you will get besides more output is more heat. I may do the same with my Darth. 8)

So, I got tired of waiting for next week and removed the resistors and put jumper wires in. Now it reads 7.5 amps on high, but of course, now I'm having trouble with Hall sensor positioning. Oh, well, live and learn.

I added some Copper to the heat sink, below the original Aluminum shelf and used larger wires.

It's just not an impressive light. I still favor the King over this light.

I finally got in the mood to do some modding and jumpered the resistors in my Darth. Lumen output went from 1450 OTF to 1911 OTF. Pretty fair upgrade for the light but not impressive compared to other triple XM-L lights. Switching to XM-L2 on copper MCPCB would probably put me over 2000 easily but it's not really worth it. It's still a damned small light with great output for it's size. Build quality is still superb compared to most other budget lights. A simple mod to make a good light even better. :)