Sipik sk98; XML-U3; 4.2Amps

After Grainde got me thinking abt a super cheap useful flashlight I decided to pimp my flashlight also. (http://laserpointerforums.com/f42/pics-added-sipik-98-4-amp-flashlight-mod-82310.html)

---Driver---
I started with the AMC driver at 3040mA and bought a extra set of AMC7135 chips bined @ 380mA ea. So I stacked 3 of those bad boys and went to ~4.2Amps!

Went with a driver to avoid the woeful super sag; when direct drived lights get exponentially dim as the voltage drops. Not to mention the perks like protection below 2.6V and 3 Hi/Med/Low ( I use low a lot already)
---Emitter---
To go all out I got a XML-U3 (couldn't find a cheap L2-U3 )
I also successfully de-domed the old T6 with gas. It only took like ~4Hr in the hot sun and just fell of (keep it upside down though), but left the dome on the U3. Maybe some other time..
---Host---
Since my other light gets really hot I decided to put loads of copper in this one. It works quite well since this one a whole Amp higher it gets much hotter, but it runs for a long time before it burns my hand :eg:

I just added more to make the spring longer, and the chips were easy to solder since I upgraded my old beast of an iron to the fancy Weller. Other than that Just slapped some thermal epoxy and compound to the star and copper.
PICS PICS PICS



Ready to drop in!


The beam is still visible with a full moon, and the battery was only @ 3.6V; Its even better now @ 4.1V

Really nice build Bacon! +1

Just curious though are you sure its running at 4.2 A the whole time? I ask because those drivers are linear and that means it cant boost the voltage. Im by no means an expert in drivers, but as far as I knew the linear will drop out of regulation if the voltage isnt enough. So when the battery voltage reaches the LED Vf the driver can only supply the vf from the battery at the corresponding current on the IV curve, which will be less. I have neglected the drop out of the linear regulator as I think the AMCs dont have the standard 1.25 V drop out of eg Moh linears? Unfortunately the AMC drivers can only take one battery, as 4.5 V is the max input voltage.

I could be wrong but perhaps you could run the light linked to a DMM directly at the LED (slightly more accurate) and watch the current supplied to the LED as the battery potential drops?

Anyway great job and enjoy! :beer:

your killing it like a boss

grainde said:

Really nice build Bacon! +1

Just curious though are you sure its running at 4.2 A the whole time? I ask because those drivers are linear and that means it cant boost the voltage. Im by no means an expert in drivers, but as far as I knew the linear will drop out of regulation if the voltage isnt enough. So when the battery voltage reaches the LED Vf the driver can only supply the vf from the battery at the corresponding current on the IV curve, which will be less. I have neglected the drop out of the linear regulator as I think the AMCs dont have the standard 1.25 V drop out of eg Moh linears? Unfortunately the AMC drivers can only take one battery, as 4.5 V is the max input voltage.

I could be wrong but perhaps you could run the light linked to a DMM directly at the LED (slightly more accurate) and watch the current supplied to the LED as the battery potential drops?

Anyway great job and enjoy! :beer:

Click to expand...

Yes I have actually thought about this.. I'm just calling it an optimistic "4.2A" (quotes) even though it is probably not; after all it is only one battery with all of that overhead before it can even be turned into light. The original driver had a flaw so when I got this one the chips were cheap so I went crazy with it

When I get another flashlight (of a different brand perhaps) it will be a two battery flashlight so it can push more goodness to the led. (Maybe even the skyray king)

Crazy question: What multi-meters do yall use? (Mine doesn't read amps)

I bought the cheapest digital multimeter I could find on the internets. Works fine for what I need it for. Does 250mA current readings and <10A readings. Has numbers I can read.

What numbers can't you read?

Can you read - 34564354.2435267658e-4 ?

Hey Bacon maybe post a pic of your DMM? I have never heard of one that doesnt read amps. Normally you have to change to the dedicated amps plug for readings in the amp range and it will be marked "10A" in text next to the red jack. The Amps readings are marked in a second set of outer numbers skirting the voltage settings. :beer:

grainde said:

Hey Bacon maybe post a pic of your DMM? I have never heard of one that doesnt read amps.

Click to expand...

the one provided to us at work doesn't have any.

Wow even the cheapest of the cheap ebay and amazon ones have that function... Sounds like yours are some special ones especially considering the price....

@ Bacon how do you know what your current is if you couldn't measure it? The current you set with the number of chips and the current you'll get, are two different things...:beer:

My DMMs at home do have the amps function but I don't use them. I made a dedicated ammeter using a DPM, current shunt, dc-dc converter and cellphone battery built into a project box.

I avoid using the built in meter's amp range if possible because one time I blew the probe tips when I forgot the probes were connected to the 10A jacks and stuck the probe to measure 220V mains. Poof.

Yeah I did something similar on a 140 Ahr 12 V battery once...Lots of sparks and I actually saw 105 A on the display for a fraction of a second. Gave me a bit of a start, but surprisingly the DMM still worked fine! :beer:

Sorry for the delay (been workin overtime) :can:

I needed anything to test some wires in the house and the $5 meter (which is freaking analog) seemed cheaper than the fancy ones on the shelf. It strictly only has like this:
10,50,250,500 DC and AC side

I like analog things for the cool factor. However analog multimeters are not fun. Once I had it on the wrong voltage for ac and upon plugging it in the needle jumped so fast it smacked the other side like a rocket. I now find that those proximity testers are easier for a quick (will it zap me?) are better than a $5 multimeter...
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Grainde said:

Yeah I did something similar on a 140 Ahr 12 V battery once...

Click to expand...

*Offtopic Ever heard of those super capacitors to start a car?