HAAALP! Lumentop TD16 pushing 6.4amps! Am I missing something?

Flashlight Modding and DIY Parts
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Hey guys, first off want to say thanks for any insight and help you can give on my question here. I am an engineer but not an electrical engineer. My field of discipline is more mechanical in nature - specifically fluid dynamics, turbine mechanics, metallurgy etc. BUT I do play and think I have at least a fundamental handle on the basics. I can look at a circuit board and know what I’m looking at and have a basic understanding of what each component does.

Anyhow, I have a recently aquired TD16. I have not torn it down yet to see exactly what’s done but it is pulling on average 4.5 amps from the tail on a fresh 25R or HE2 18650. A nice light.

Looking at the tube with the 18650, I determined that a pair of 18350’s would slide right in. The light is listed to run 4.2-8.4V and utilize 2 CR123A’s. Yep, they fit. I clicked that bad boy on and WHOA! Large increase in output. I mean holy moly, wow, this isn’t right bright. :open_mouth: (I own a SD75 touching 6000lm so I’m not gobsmacked, it really was pushing hard!)

So I measured the tailcap with both cells and it was 3.2 amps. Now last I checked, doubling the voltage halves the amperage for the same net wattage output. So am I wrong in thinking this driver is now sucking 6.4amps? I don’t know what it’s seeing at the LED but I don’t want to smoke the bonding wires. I’ve never driven an XML-2 this hard before. Do I have the math right, and should I be concerned about this light pulling 3.2amps at 8.4v? If the LED was seeing the higher voltage and lower amperage I wouldn’t be concerned. But I have to assume the driver is dumbing the forward voltage back down and by default increasing amperage back up…no?

I’m calculating about 19w with the single 18650 and 27 with the two 18350’s. I get that with higher voltage comes some efficiency gains, but hat seems like a pretty large jump. Especially considering the driver is designed to work within that voltage range.

So what say you guys? Am I going to fry the chip or do you think I am just a newb shocked at how hard an XML2 can be driven? LOL :partying_face:

TIA,

J

Edit because I wrote volts instead of amps in a critical area and did some basic math wrong…of course!

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Your math is right.
I wonder what efficiency that driver have.

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I own the same light so I’m interested. Any idea at all of the lumen output with (2) 18350s? What brand were u using?

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So I’m wondering if the lumintop td15s would do the same?

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I would love to know myself. LOL Now that I see there were not many replies on the subject I think it’s time to do some more digging with this light. I’m going to contact the original owner and see exactly what was done if I can’t figure it out myself.

If I had to guess it was just shy of the 2K figure. I have some lights that are in the 2300 range but are more floody so I can’t do an A-B comparison. I’ll tell you this though, at 6.4 tail amps, it was rocking! I’m just concerned the light is going to go dim for a second and then…plink - dead.

The 18350’s I purchased were for my Manker E14/Astrolux S41. I took a wild chance and tried the Demonfire 18350’s off Amazon Prime. I figured if they were inflated Chinese garbage I would just return them via the Prime policy. :smiley: Turns out, the capacity was inflated at 1200mah - no shock there - but they put out a fair amount of current. On my stock S41 it was pulling about 5 amps on an 18650 HE2 and 3.8ish on the 18350. With half the capacity I think that demonstrates the 18350 could put out pretty good. They have been going strong so… I ordered NiteCore’s new 18350 as well to see the difference.

I’m wondering if the mystery mod done is causing the driver to gulp down current with the higher voltage where it normally wouldn’t. For whatever reason it’s pulling amps hardcore.

Demonfire 18350

NiteCore IMR 18350

Welp, if I’m not mistake the TD15s has the same voltage range and can run two CR123s’ as well so…maybe? Like I said above though, I’m wondering if it has anything to do with the mystery mod done to this light. It’s time to dig and find out what exactly was done to it. There is not even a spring by-pass done, so I’d imagine it’s not something hardcore. Maybe a resistor jumper?

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If the LED dies you can put in a SST-40

On DTP star the LED should be fine, older XML2 did not blow the bond wires so early, so if its not dead now probably lasts a long time in the light

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If it’s high bin XP-L or W2 emitter, even XP-L HI V3’s Ive seen amp pulls of 7.2+amps at 4.22v-4.25v They’re still running fine, I doubt very much the LED is seeing it, and even with the spring bypass there is still loss due to resistance up to the LED. When I test my lights for throw I use a 10awg short length of wire to check amp draw, I also use it to check throw, and when I check with the tail cap on, even bypassed, it’s usually quite a bit lower.

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I bet your TD16 have demons inside :smiley: :smiley: