Can you show a picture head-on of the location to be modified? Or a drawing?
“for those without fine SMD soldering skills”
WILCO once I have mine, and am more confident that component selection or layout is not critical to results. Not anticipating a surprise, but one never knows until tried ones-self.
Even perfect program verification can only establish that a program meets its specification. […] Much of the essence of building a program is in fact the debugging of the specification.
Fred Brooks (1986)
Thanks for your reply Tom Tom. Is this a suitable capacitor? http://www.ebay.com/itm/10pcs-1206-107Z-100uF-16V-chip-SMD-Ceramic-capacitor-/292207189605?epid=2163346082&hash=item4408e7de65:g:AZEAAOSwcB5ZHHEp
I’m not too sure where to even begin with the size and the voltage but the picture looks similar 
If I order the capacitors now it’ll hopefully give enough time for others to take some additional pictures so it’s easier to follow. I wouldn’t want to fry it accidentally by shorting it out. Thanks for everyone’s help!
> bicycling
Bumpy ground causes jerks forward/back as well as up/down
and you certainly want the light to stay on if you crash your bike in the dark and get thrown over the handlebars, for example.
Stuff happens.
https://www.google.com/search?q=define+jerk+physics
https://en.wikipedia.org/wiki/Jerk\_(physics):
In physics, jerk, also known as jolt, surge, or lurch, is the rate of change of acceleration; that is, the derivative of acceleration with respect to time, and as such the second derivative of velocity, or the third derivative of position.
You see the cap beside the 3 wires. I removed the protection over the ground trace of the board and soldered the cap vertically with one end to ground. Then connected the other end of the cap with the “meeting point” of C2 and D3.
Here is a schematic of the driver:
On the face of it it, it looks a suitable physical size and value. 1206 is bigger than 0805 (but the minimum for this sort of capacitance value I think).
It won’t just stack on top. e.g. Flashy Mike showed his stacked on one end, and a fine wire link to complete the connection. Fine SMD soldering skills.
However I don’t recognise that dielectric (107Z ?), which might be sub-optimal for stability. But we don’t yet know the minimum that will be a solid mod. It could be a lot less.
Suck it and see is where we are at the moment, I think FM is still the only pioneer yet.
I would give it a go, knowing too much I can anticipate all sorts of esoteric issues that are probably irrelevant. If it isn’t perfect, stack on a second one. For $1.50 you have ten to play with 
A named class 2 dielectric like X5R or X7R would give me more confidence.
Holy simultaneous post
Edit: You could even stack it on one of the un-used LED- pads and wire it over to D3/C2 junction as a test, but that might not be best, depending on how the ground plane is laid out.
I don’t think so. LED- is not connected to ground, it’s switched by FET and 7135.
You are quite correct. Sorry for stupidity. Is there any other large Gnd pad exposed, e.g the ones around the 7135? or is scratching off solder mask essential ?
There is a pad directly at the 7135 which appears to be connected to GND, don’t remember why I haven’t used it.
That’ll do
Ok, I’m not much of a modder but this I think I got.
Springs are bypassed and all screws, apart from the one holding the reflector, has been replaced.
It’s been cleaned up and everything makes much better contact now.
The reflector has been turned like .5 - 1 mm for better centering of the leds.
Have only tested it for a very short time in the back yard and it’s hard to say how much brighter it is, but it sure is getting hotter.
Before mod the light was warm, but not hot, after three minutes when it stepped down.
Now the head was to hot to touch and the body was quite hot too.
The light indicated 60 degrees.
So…
How can I measure the current being drawn?
And what’s the highest temperature before causing any damages?
Once you start modding something as potent as the Q8 you are on your own.
If current draw is of interest, best mod the tail pcb to put in a clamp meter loop. Of course you will need a clamp meter also.
Once it gets too hot to hold, turn it down.
There is no temperature “before causing any damages”, well, until you start melting the solder. The harder you drive the LEDs beyond specification (current and temperature) the faster they will degrade. From 1000s of hours to just a few. Modders realise this, accept the compromise and will replace.
As supplied (particularly no spring bypasses), it should be very reliable, last almost forever, and operate in a safe efficient region where LEDs and cells perform at their efficient best and still put out loads of light.
It is not compulsory to immediately crank up a well balanced torch just because you can.
You have already observed how much hotter your’s runs than standard, that should be a strong clue as to how much additional stress it is getting.
Q8 in double M4 magazine pouch
I know I have another set of loaded lbe here somewhere - one is standard for use with a normal molle pack and the other is ranger style suitable for use with a ‘chute - and I know some had FSNs on them. I bought like 8 of these M4 pouches years ago when I pieced together a near complete molle set with gen IV frame. In some ways ’more than complete’ might be more accurate. Previous generation pack and shoulder straps required mods and fabrication of lashing straps and a bit of ingenuity to make it work.
On my own? That’s what I thought this forum was for. So I wouldn’t be on my own. Therefore the questions.
And I know I don’t have to do anything with this light, but it’s fun and a way for me to learn.
Of course the higher levels of current and temperature eventually will effect the LEDs, and when/if that happens I guess I’ll have to learn how to do a LED swap.
Until then I’ll be happy with this as it is now, and maybe buy me a clamp meter.
Thanks :+1:
I believe the “on your own” comment meant that as you tweak and mod and push the light, you’re dealing with much more power running through the wires, traced and components and that can lead to unexpected results. When it’s in your hand and chugging away with all of those amps, the forum won’t matter much as you won’t be able to quickly get the answers you need as the heat builds up and parts can potentially fail.
Got it. Thanks
Well, it’s not my first mod. But I don’t consider myself a modder, yet.
Sorry if “on your own” came across badly. I meant that once you start increasing LED current etc. seemingly minor things can have major effects, e.g. how well the thermal paste has been applied under the MCPCB, how well the LEDs have been flowed onto it and whether the direct thermal path soldering is perfect, quality of LED wire solder joints, etc.
This is where what works for one person may not work as well for you.
The question of “what’s the highest temperature before causing any damages?” is unanswerable, and anyway depends on where the temperature is measured. If referring to the temp. sensor in the MCU, it is only incidentally related to e.g. LED temperature, and then only under steady conditions.
The first step of bypassing the springs should also be done knowing that you have removed any protection from e.g. accidental reverse fitting of a cell, or poor contact so that e.g. worst case only one cell is actually in contact and taking the full load of a high current modified torch, etc. and safe use is now entirely your responsibility.
No worries.
Got it, and I’m aware that higher current not only brings more light but also could cause unexpected issues.
If it goes FUBAR on me and I can’t fix it I guess I’ll buy a new one and call it a lesson.
I’m rather careful regarding my cells so I hope that won’t be an issue.
I also have a few modified lights, some by me and some by others, and I sure won’t let anyone else use them. Just don’t trust people… :person_facepalming:
Thanks