Awesome mod!
20 Watts is still quite a bit for such a small thermal mass of aluminum, but like you said, decent moving air will help dissipate the heat much better.
Do you think the whine comes from the inductor, could possibly running some CA on the coil help reduce the transformer whine?
I am thinking that a very thin slathering of heat sink compound on the outside of the copper pipe would not only help with thermal transfer but act as a lubricant to help press the pipe in
Thank you WarHawk-AVG.
I'm not sure where the sound comes from. I've done several mods like this and each one that I reflowed a pin or two down to the PCB has whined. One I completely air wired and it doesn't whine. So maybe the MCU itself if whining and then certain driver components resonate with it. You have given me an idea. Sometimes I use a screwdriver as a makeshift stethoscope to pinpoint the source of a noise within a automotive engine or accessory. Next time I need to try the same technique on a driver.
Your idea for the thermal paste is a good one. I will try to keep that one in mind.
Thanks for your input. Good stuff.
Thanks ImA4Wheelr…
I’m enjoying these mods…My wife thinks I’m nuts for playing around with $40 lights, going out to the backyard at night taking pictures, hooking up meters to the lights, etc.
Got an HS1010 on order off ebay for $10.99 (USD) shipped. And some resistors off Fasttech. As-is, by adding thermal paste between emitter base and pills (very little in stock form), and thermal paste between paste and housing, the housing now gets a LOT hotter, and a lot quicker than it ever used to. But I do think that if I bump up current, I will need to draw on your copper thermal path upgrades in this thread.
Man neons97, you are in the thick of it already. You must be a very fast learner. You're way ahead of where I was when I had a similar level of light modding experience. In fact, you sound close to catching up to me. Good on you. We need more modders around here. I hope you stick around after you finish your bike light.
Regarding my copper mod. I can be a bit trigger happy when it comes to stuffing copper in a light. It may have been adequate to just upgrade to Notigons/Sinkpads and thermal paste. My instincts told me that there was more than just the aluminum stars causing the thermal sag. That was based on how the sag was not immediate and how it continued to increase throughout the test run. It would be cool when you get your lux meter, if you would check for thermal sag and report back. If you end up showing I over killed, that is fine. I rather know the truth.
So sorry to bother you again on this. Do you know if your reading was actually 25mV (.025 volts)? Now that we know for sure you have the same driver in Post 1, .25 volts doesn't make sense.
I made a mistake in my decimal place. It is .025. I’m learning accuracy of my measurements and documenting them is extremely important in these forums. No estimates and remembering in my head.
You guys are pretty scientific about all of this.
I also ordered a few parts to upgrade my old Gemini Titan with a ssc p7. The driver was putting out 2.5a on my good battery pack. So I figured a switch to an xm-l2 would be a nice upgrade. With the big reflector, I put in one f the xm-l’s I took out of the ssx2. It is spotty but not too much of a halo. Would make a great helmet light for one of my riding buddies. And good amount of mass so going 3a hopefully won’t be problematic with a single emitter.
I’m just not sure if I should go panasonic 18650 through hunk lee or go lipo.
I’m comfortable with lipo but I got rid of all my rc gear afew years back. And I know I’m not the type to settle in on a $30 hobby charger when my old Chargers were high end units with dual 400w charging channels. :). So I fear this may get expensive. With the 18650, u would just keep using quality Gemini/gloworm wall wart chargers.
What PSU do you have? Ignore my previous comments about the driver’s ability to handle 3s, that was based mostly on the bad data. Based on the new data you’re just seeing normal behavior for a QX9920 I think. I now see no problem.
If it suddenly cut off without dimming I’d assume that it’s the MCU’s LVP stopping the output rather than limitations of the buck circuit. I could be wrong though.
ImA4Wheelr and I aren’t just asking about the sense voltage for curiosity, you should check that again. With such a low sense voltage I think precision adjustments (eg precision low-value resistors) may get expensive. Instead I’d look at the link I provided in post #26. If you follow that thread you’ll end up over here (#106) where Pavithra_uk explains how to calculate the gain on your op-amp. Adjusting the gain may be the easy and cheap way to change your set current.
In fact, I just glanced at the pics in reply #1 here and I see the 153 and 202 resistors (15000ohm and 2000ohm). Looks like the gain is set exactly the way Pavithra_uk described for the SRK over there. Reducing the gain as described in some of those posts will push your sense voltage even lower, giving a higher set current with the same sense resistor (R010). You can pickup a large 0805 component assortment (I assume that the 153 and 202 resistors are 2mm long, right? That’s 0805.) from Sure Electronics for <$9, I’d recommend that.
More to learn and digest. Will go back tonight and document everything and read your suggested posts.
I just ordered these:
https://www.fasttech.com/products/1007902
So basically, I can either adjust the gain on the OP Amp or adjust mod the sense resistor. But the easier of the two to mod is the OP Amp gain due to its larger size, and the higher resistance requiring a less precise resistor.
I think I”ll have something in this pack that will get me going from 2.5A to 3.0A.
You 2 just got into deeper territory than I understand. I'm watching and trying to learn from here on out.
Just picked up a pair of lipo’s off HobbyKing for $18 ea. (2s2p, 4000mah, 5C discharge, built-in PCB with 2.85V LVC (too low in my opinion) and a 4.2V charge cut-off. They’re meant to be put into RC transmitters. Technically you can charge these with a standard wall-wart LiIon charger without a fancy Lipo hobby charger with the built-in PCB. But I got a cheap Hobby King hobby charger on order as well.
With their 5C constant discharge, and lipo chemistry, I should be in the optimal voltage a lot longer than my existing packs (even my best 3-year old Samsung 5200 pack). My rides now are all morning rides at 6am, so it’s light out by 7:30am so 90 minute runtimes on a 2.5A (emitter) draw should be no problem. Especially since the lipo has built-in LVC. And the batteries are only 133g…far lighter than 2s2p 18650 at around 200g. I also ordered some really nice 24ga silicone wire from HobbyKing (I used their 12-14ga all the time in RC) and will re-wire my lights with this higher quality silicone wire.
Will be riding and won’t be opening up these lights again till my resistors arrive from FastTech (around 3-4 weeks). Will post results and beam shots probably in early December.
Get yourself a 3V LVA/C. I have an ebay PCB with a 3V/cell cutoff and max 15A continuous current bench tested and voltmeter to get a general info(https://www.fasttech.com/p/1222902). Good luck with LiPo, I run it and like it 
Great thread anyway, still a lot of stuff here to learn from 
What for? Doesn’t the driver already have LVP & charge level indicator lights for 2s?
In my RC days, you kept your cells at 3.3V cut-off. Maybe because we were drawing 20-30A continuous on average, we needed 3.3V otherwise it would drop too low too fast at 3V. But this pack I got has a 2.85V cut-off, meant for an RC transmitter, which draws in the mA range. So 2.85 may be okay for that low of a draw.
The light’s LED voltage indicator will not work as well for these bike lights since lipo holds their voltage much longer. So when you get down to just one LED, it is in a much lower state than on 18650 cells. So the danger is you don’t really have much back-up time once you get down to one LED. Also, over-discharging 18650 is much less risky/dangerous than over-discharging a lipo.
I have a LVA on order that plugs into the balance port. But not an actual cut-off.
I don't do bike lights, but that is one heck of a great mod and some good info there as well. Thanks for posting the mod.
Excellent mod and write up! Certainly has the wheels turning.
I believe I may have a heat problem with one of my X2’s, both of which don’t have the pressed in pills. One of the units gets MUCH hotter than the other (mainly on top), with outputs being relatively similar.
Is this a sign of good or bad heat transfer? (In regard to the hotter unit) My gut says this is good, however the hot unit, has the worst contact between the led board and unit body.
I don’t claim to be an avid MTBer but anyone who claims to be one will tell you that the answer is no bar/frame heat sinking
as they’re all carbon :-).
Ok, my bar is also carbon but I’m just a wannabe.
But yea, incredible helmet light there ImA4Wheelr. My new helmet light will be a quad flashlight, yippee…
O-L wrote:
I don't do bike lights, but that is one heck of a great mod and some good info there as well. Thanks for posting the mod.
Thank you O-L. If you ever want a change of pace, you should consider modding them. I'm sure there are many bikers that would love to have an O-L custom on their bike/helmet. The good thing about the bike lights is that you don't have to deal with battery storage.
cardnation wrote:
Excellent mod and write up! Certainly has the wheels turning.
I believe I may have a heat problem with one of my X2’s, both of which don’t have the pressed in pills. One of the units gets MUCH hotter than the other (mainly on top), with outputs being relatively similar.
Is this a sign of good or bad heat transfer? (In regard to the hotter unit) My gut says this is good, however the hot unit, has the worst contact between the led board and unit body.
Thank you and welcome to the forum cardnation. You are correct. Feeling heat come out of the light is a good thing as it is escaping from the emitters.
It's hard to see differences in light output but due our perception of light and due to the way the human eye adapts do different light levels. The best way to determine if your emitters are overheating is to get a lux meter (An HS1010 costs less than $15) and see if output drops in the first 5 minutes of operation on high in an environment that you anticipate operating the light. Ideally, you should simultaneously measure current the emitters to make sure the output drop is not due to other issues, but that involves much more work.
sista94 wrote:
I don’t claim to be an avid MTBer but anyone who claims to be one will tell you that the answer is no bar/frame heat sinking
as they’re all carbon.
Ok, my bar is also carbon but I’m just a wannabe.
But yea, incredible helmet light there ImA4Wheelr. My new helmet light will be a quad flashlight, yippee…
Thank you sista94. By the way, I've been meaning to say I like the new avatar. That looks like some great biking country there. Do you do anything special to avoid rattle snake bites out there (special guards or something)?
Good point on the carbon. I guess they just have to petal faster when they need to cool their lights down.
EDIT: Added another paragraph to reply to cardnation.
Hi,
i also ordered a SolarstromX2.
I ordered i @ fasttech.com (https://www.fasttech.com/p/1285800 | “X2, 1*Cree XM-L U2, Black, US Plug ”)
Is ther also a solution for the current mod? (i cant find a R010 on this PCB, only a few R300 => see image)
Where did i get the hardware version that can be used for this mod?
thanks
mastercheef
Hi mastercheef. Welcome to the forum.
As you suspect, the 3 R300's are your voltage sense bank. Combined they have a resistance of .1 ohm. I don't have any experience with your driver. So the best I can tell you is that adding an equivalent amount of resisters (would bring overall resistance down to .05 ohms) would theoretically double your current. Don't know if the rest of the driver can handle that level of current though. It's best to connect a DMM in series with the emitters and measure current to the emitters while making smaller steps (e.g. adding one R300 or R200 at a time).
Obviously, make sure your emitters have decent thermal connection to the host if you really start jacking up the current.
Best wishes. Keep us posted.
hi, thanks for your quick answer,
ok thats clear (each resistor has 0,3 Ohm => in pallel so its 0,1 Ohm)
=> if i add additional resistors must i do this by each of the 3 R300? (cause i can’t see the circuit path at the other side of the pcb, so i don’t know if the resistors are connected in series or parallel)
=> where did you buy your solarstorm?