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Some questions about the Shark driver

kenster

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Nereus, so this 0,10 ohm resistor is not a sense resistor like in Waynes other converters. Otherwise you would have to raise the resistance to achieve a higher current to the LED. Right?

Ken

Notice the , instead of . :grin2:
 

Nereus

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Shark is a bit different story compared to other Shoppe converters. The output current is primarily set by a small potentiometer on the circuit board. However, there is upper limit for the current and that is set by the resistor. And when it comes to setting the upper limit the resistor acts just like any sense resistor. The only difference is the fact that it only kicks in when the current is about to exceed the limit.

For Shark, the formula for the max current is Current=0,1/Rsense. E.g. 0,05 ohm sense resistor puts the upper limit to 2 amps. But if the potentiometer is set to some lower output current value, say 1,5 amps, then that is going to be the output current.

Hope this helps :)

-N
 

DaFABRICATA

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I have 3 SSC P4 emitters wired in series to the shark ......will this work ok without overdriving the LEDs?
I just want to be sure this will work fine before going any further.
 
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kenster

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If you haven`t changed the resistor which you stated in in an earlier post you were not, then even if the trimpot was turned all the way up the most the current be about 1 amp. I think it is actually 980ma but,..... what`s 20ma?!?:grin2: Don`t hook up a series of batteries that is higher in voltage than the total vf of the string of LED`s. I believe two Li-ons would be great. I`m still learning about these drivers but I am 99% sure I know.......... Nothing!:huh2: :ohgeez:


Ken:laughing:
 

65535

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From my rather extensive talks with wayne about using a shark in a tri cree mod, I would say this is about the most versatile board around, great UI and user friendliness.

So for 3 LED's you recommend J1 jumpering it? and using the trim pot (hall sensor) to change output current? And it will limit the voltage to only what is required to drive the LED at such a voltage.
 

wquiles

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Has anyone used the Shark to drive a single 5W LED from a single 18650 LiIon cell? Would this work at, say at about 1Amp drive?

Will
 

DonShock

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I used one to drive a Lux5 off of 3D cells, pretty close to an 18650 in terms of voltage, with no problem.
 

chanamasala

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Is there a positive contact pad on the other side of the circuit board? Are the edges ground?
 

luminari

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Looks like they're back in stock! Mine should be arriving today.
 
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luminari

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dat2zip said:
The primary current sense resistor is a 0.1 ohm resistor which sets the upper end of the current to 1A. Cutting this value to 1/2 would increase the upper current limit to 2A for example. I would solder a 0.05 0603 in place of the current 0.1 ohm sense resistor.
Wayne

Hi Wayne, I'm looking forward to getting my first shark today. I was wondering, will you consider selling Sharks with this sense resistor replaced with a .05 ohm resistor soldered in place from the factory? Also, if properly heatsinked, will the 2 amp board function normally (e.g. within specs) and exhibit a similar lifespan as a 1 amp Shark?

That would be great with new LEDs being released that can handle higher current, and would help "future-proof" our purchases. I'm a bit leery of screwing up when soldering such small resistors as I need this thing to be bulletproof! Thanks for making this product!
 

luminari

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Ok, board is all wired up and ready to go. Except it's still at the 980mA limit.

Could someone tell me which resistor is the sense resistor so I can replace it myself? :) I know Wayne and the Ms. SS are busy people.
Shark_wiring.gif
 

dat2zip

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The sense resistor in the wiring diagram is next to the arrow pointing to LED+. It's to the left of the arrow head and LED+ hole.

The easiest way to make a 0.05 is to solder another 0.1 on top of the existing 0.1 ohm sense resistor.

Removing SMT parts is hard.
 

luminari

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Ok, thanks Wayne.

Will running at 2A output shorten the life of the Shark (assuming I heatsink it properly)?

Also, will you consider selling a shark with this resistor replaced to a .05 ohm and the pot removed or unsoldered? My Paypal is ready! :)
 

dabiscake

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Wayne, could you confirm that computing the resistor values for this Shark board is different from the Badboys/DownBoys? 0.05 Ohm was the sense resistor value for 1A (2x 0.10 Ohm) in those boards, now for the Shark, 2x 0.10 Ohm = 0.05 Ohm is the value for 2A output?
Sorry, I've read your posts above, just wanted to confirm before blowing anything up!
Thanks!
 

ghadlock

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I saw some questions regarding soldering to the Shark and though I'm no expert I have found a method that works, particularly when you want the wires to the LED to exit from the bottom of the Shark board and through a heatsink, meaning that you are soldering the wires on the top of the board in the middle of the circuitry. After some trial and error and having to unshort everything in the general vicinity of the LED+ LED- connections with desoldering wick, I came up with an easy clean method that works well for me.

I've been using solid copper wire (18 or 20AWG), and I first put the Shark into a third hand to hold it, then touch the soldering iron to the BOTTOM of the board where the LED+ or LED+ wire enters. I then insert the solder into the LED+ or LED- hole from the top of the board so that a bit of solder melts (soldering iron is at the bottom of the hole) and partially fills the through-hole. I do this for both holes (LED+ and LED-) so they each have some solder partially filling the hole. I then strip my wires (I strip them just a bit longer than the thickness of the board), push the stripped end of the wire against the bottom of the LED+ / LED- hole on the bottom of the Shark where it is to enter, and then put the tip of the soldering iron against the stripped portion of the wire. In about 2 seconds, the solder in the hole melts, the wire pushes in up to the insulation, and you have a 'perfect' solder on the top of the board without shorting everything out. If too much wire is protruding on the top of the board, I simply trim it a bit. This method is fast, easy, and works every time...cut my Sharking soldering time from about 20 minutes (about 15 minutes of cleaning up potential shorts) to under 5 minutes with better results. Again, I'm not an expert at this but thought I'd share what works for me.
 

luminari

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Cool, thanks for the tips, ghadlock!

I'm mainly a bit concerned about desoldering that tiny potentiometer built onto the circuit board. One slip of the iron and the board is toast.

Does anyone know how many wipes that built-in pot is good for? Maybe I should just leave it alone and drill a hole in the light for occasional adjustments.
 

Nereus

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+1 to the comment above by Duq - IIRC the potentiometer is rated for only few dozens of swipes (say, ~20 swipes). It is designed for one-time permanent setting of the output current and then it should be left untouched.

-N
 
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