# new P7 driver 3amps?



## DocD (Jul 6, 2008)

did any of the experts get a look at this http://www.kaidomain.com/WEBUI/ProductDetail.aspx?TranID=5296
is it realy 3 amps thanks DocD


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## spencer (Jul 6, 2008)

Looks nice. I don't know what the bottom thing means about only putting out 1A.


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## 1 what (Jul 6, 2008)

I'm not an expert but I ordered 1 last night.....We'll see what it's up to when it gets delivered.


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## darkzero (Jul 6, 2008)

http://www.cpfmarketplace.com/mp/showthread.php?t=180676


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## spencer (Jul 8, 2008)

I think I'm going to order one. I'll let you know how it goes.


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## climberkid (Jul 8, 2008)

wow i should probably get one of those for sure. but i will wait to see what you guys have to say about it.


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## rizky_p (Jul 9, 2008)

Look nice on the spec but quite expensive for me...I'll wait for someone to test it out.


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## James35 (Jul 9, 2008)

rizky_p said:


> Look nice on the spec but quite expensive for me...I'll wait for someone to test it out.


Really? $12 is expensive in comparison to the the rest of the light? In my opinion, ALL of these driver boards I've found are a steal! Even the best D2DIM is only $20. 

Let's say you were going to make a Mag 3D P7 light:
$20 Mag 3D 
$27 P7
$20 heat sink
$12 driver
$36 batteries
$15 MOP reflector
$6 lens
$5 charging jack
$2 thermal adhesive
$3 bicycle tubing
$5 wire
$20 shipping
Total = $171
This $12 driver is only 7% of the overall parts cost, not to mention your time in building it.


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## marschw (Jul 9, 2008)

Well, it may not be a large percentage of the price of the project, but that's not an excuse for the seller to overprice it...

BTW, my Mag 6D P7 project was:

Mag 6D: $25 (Fry's B&M)
C-bin P7: $23 (DX SKU 12721)
Heat sink: $14 (DHS's)
Driver: $6.50 (KD SKU 4338)
Batteries: $59 (all-batteries.com SKU 835: 4x F-size 14Ah NiMH) :mecry:
Reflector: $5 (DX SKU 12229)

Things like wire and thermal grease and glue I had on hand, and shipping was free on everything. Total=$133... but I'm probably gonna buy the expensive driver anyway just to test it out. :twothumbs


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## James35 (Jul 9, 2008)

More power to you if you can make a driver for less than $12. I can't. Not worth my time.  I'm very appreciative that we have such nice choices out there for such low cost.


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## JustinS (Jul 10, 2008)

James35 said:


> Really? $12 is expensive in comparison to the the rest of the light? In my opinion, ALL of these driver boards I've found are a steal! Even the best D2DIM is only $20.
> 
> Let's say you were going to make a Mag 3D P7 light:
> $20 Mag 3D
> ...


 

Can I ask what the bike tube is for, is it for going over the drivers??
Cheers
Justin


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## rizky_p (Jul 10, 2008)

Well i just dont expect 12 dollar driver came from KD.



James35 said:


> Really? $12 is expensive in comparison to the the rest of the light? In my opinion, ALL of these driver boards I've found are a steal! Even the best D2DIM is only $20.
> 
> Let's say you were going to make a Mag 3D P7 light:
> $20 Mag 3D
> ...


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## James35 (Jul 10, 2008)

JustinS said:


> Can I ask what the bike tube is for, is it for going over the drivers??
> Cheers
> Justin


It's for the outside of the light. This can be helpful for 3 things: extra grip, insulate your hands from the cold light in the winter time, and protect the charging jack from water.


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## marschw (Jul 14, 2008)

I just noticed, the layout of the board looks similar, if not identical, to the unpopulated underside of the driver in the EYJ-XAQ5. It even has that odd little peg for a center contact.


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## DocD (Jul 25, 2008)

Did any one get there hand on this diver? Yet and any of the spec's to see if there right?


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## TorchBoy (Jul 25, 2008)

*Re: New P7 driver 3 amps?*



spencer said:


> I don't know what the bottom thing means about only putting out 1A.


That appears to be the draw on the battery. The whole thing is messy and unclear, but I'm particularly disappointed the spec writer can't make up his mind whether it's 3.0 amps or 2.8 amps.


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## darkzero (Jul 25, 2008)

*Re: New P7 driver 3 amps?*



TorchBoy said:


> That appears to be the draw on the battery. The whole thing is messy and unclear, but I'm particularly disappointed the spec writer can't make up his mind whether it's 3.0 amps or 2.8 amps.


 
Huh, that can't be right if it output is near 3A? :thinking:


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## Beer (Jul 25, 2008)

James35 said:


> It's for the outside of the light. This can be helpful for 3 things: extra grip, insulate your hands from the cold light in the winter time, and protect the _charging jack_ from water.




Tell me of this "charging jack" you speak of!?!? I posted a "wanted" thread in the custom B/S/T forum about a jack to charge cells in a mag and got nothin.

Better yet just PM me so I don't hijack this thread. THANKS!! 

:tinfoil:


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## baterija (Jul 25, 2008)

*Re: New P7 driver 3 amps?*



darkzero said:


> Huh, that can't be right if it output is near 3A? :thinking:



Quick back of the envelope calculation using 4.0 Volts as the Vf, Vin of 13.2, 3.0 Amp to the emmitter, and 90% efficiency gives me 1.01Amps from the battery with KD claiming 1.0 Amps. For a buck circuit their numbers seem to make sense. 

Another way to look at it, that is easier for my brain to wrap around, is in terms of Power.
4V*3A=12 watts to the emitter. 
13.2V*1.01A = 13.3 watts provided.
13.3 Watts *.1= 1.3 watts lost in the 90% efficiency driver 
Power to the emitter plus power lost to inefficiency (heat) should equal the total power supplied.
13.3W supplied -1.3W lost = 12 Watts provided to the LED


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## darkzero (Jul 25, 2008)

*Re: New P7 driver 3 amps?*



baterija said:


> For a buck circuit their numbers seem to make sense.


 
Oops, my mistake, wasn't paying attention. :thumbsup:


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## CM (Jul 25, 2008)

Their 90%-95% efficiency claim is suspicious. I wouldn't believe it until someone measures it and states the condition under which it was tested.


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## CM (Jul 25, 2008)

double tap


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## SUBjohan (Aug 5, 2008)

CM said:


> Their 90%-95% efficiency claim is suspicious. Sounds too good to be true.



Its is to good to be true. :mecry:
But 83,5% is good enough for me 

I have measured the thing and I have to say I like it.
Unlike I have read somewhere else these drivers do have a memory function.
They will start working from 4,7Volts, they will stop working at 4,0Volts than the driver goes into a verry verry low mode (3mA to the led).
I did'nt see any flickering 

Well here are the measurements in a excel file.

All measurements where made with calibrated meters.

Greetz Johan


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## StefanFS (Aug 5, 2008)

SUBjohan said:


> Its is to good to be true. :mecry:
> But 83,5% is good enough for me
> 
> I have measured the thing and I have to say I like it.
> ...


 
How does the memory function work? In the drivers I got it just progresses to the next level every time you turn it on. Turn it off on low and it's on high the next time you turn it on.

Your numbers seem to be good as I get ~2.7 A in the 6-7.5V range on high. ~80% is not bad. You did a lot of work to get that table on input/output, nice.

Stefan
-----------------------------
Edit! 2008-08-08.

One driver was obviously mangled in transit and malfunctioned. I rewired the other drivers and after that they seem to have a memory function when off for 5 sec. or longer. On 6 AA NiMH it will drive an SSC P7 to spec., more or less.


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## SUBjohan (Aug 5, 2008)

StefanFS said:


> How does the memory function work? In the drivers I got it just progresses to the next level every time you turn it on. Turn it off on low and it's on high the next time you turn it on.
> 
> Stefan



Just turn it off in a mode, wait a bit and turn it on again and then its in the same mode as before.

Perhaps there is a difference in drivers, because my driver also came with a sort of rubber protection thingy for the coil wich is not seen on the KD pictures.

Greetz Johan


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## jirik_cz (Aug 5, 2008)

Good work SUBjohan. If you don't mind I've made graphs from your data.


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## SUBjohan (Aug 5, 2008)

jirik_cz said:


> Good work SUBjohan. If you don't mind I've made graphs from your data.



Nice :thumbsup:


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## StefanFS (Aug 5, 2008)

SUBjohan said:


> Just turn it off in a mode, wait a bit and turn it on again and then its in the same mode as before.
> 
> Perhaps there is a difference in drivers, because my driver also came with a sort of rubber protection thingy for the coil wich is not seen on the KD pictures.
> 
> Greetz Johan


 
Incredible! They have different versions in the first batch. I have no form of memory in the ones I received. Turn it off on high, wait, it turns on in the low level next time it's turned on! And they had the rubber protection sponge.


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## SUBjohan (Aug 5, 2008)

StefanFS said:


> Incredible! They have different versions in the first batch. I have no form of memory in the ones I received. Turn it off on high, wait, it turns on in the low level next time it's turned on! And they had the rubber protection sponge.



This is really incredible!!! but not in a good way 
Perhaps Kai could give a anwser to this problem ?

Greetz Johan


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## Bimmerboy (Aug 5, 2008)

SUBjohan said:


> Perhaps Kai could give a anwser to this problem ?



In my experience, when buying cheap, "made in China" stuff, two units of the very same item produced in China will, many times, have similar, but somewhat different components. That the supposedly same driver, received by two different people, works differently should not come as a total surprise.

My suspicion is that you will not get a clear, understandable answer on this one, if any.


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## Meterman (Aug 6, 2008)

SUBjohan said:


> Well here are the measurements in a excel file.
> 
> All measurements where made with calibrated meters.



Hi SUBjohan,

Your excel file is a very good job!

I like precise measurements, in German I say "WER MIT MIST MISST, MISST MIST." It's a pity that in translation the play on words gets lost. 

How do you measure currents? My new AC/DC current clamp (Chauvin Arnoux K1) has a span from 1mA to 4500mA and very small jaws.

Wulf


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## StefanFS (Aug 6, 2008)

Bimmerboy said:


> In my experience, when buying cheap, "made in China" stuff, two units of the very same item produced in China will, many times, have similar, but somewhat different components. That the supposedly same driver, received by two different people, works differently should not come as a total surprise.
> 
> My suspicion is that you will not get a clear, understandable answer on this one, if any.


 

That can be true sometimes. I have been lucky with the stuff from China I have been using so far, but I try to select what seem to be good quality. Buying cheap has different meaning in different parts of the world, I know that it can sometimes mean 'trash' or low quality in the US. Here cheap (billigt) can also mean that you made a bargain. I think there might be different UI versions coexisting and that the seller missed this detail, and the versions are mixed. The driver works well and seem to be very well built, it's the software that differs in the sense that my units have no memory function.
Stefan


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## SUBjohan (Aug 6, 2008)

Meterman said:


> Hi SUBjohan,
> 
> Your excel file is a very good job!
> 
> ...



Yes, in The Netherlands we have the same kind of saying "Meten is weten, maar dan moet je wel weten wat je meet".

I used 4 GossenMetrawatt Metrahit 29S multimeters so could measure everything in the same time. 

Greetz Johan


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## Meterman (Aug 6, 2008)

SUBjohan said:


> I used *4* GossenMetrawatt Metrahit 29S multimeters so could measure everything in the same time.



That's really a bunch to have a lot of precision _at the same time!_

Of this series I employ a Metrahit 27M, specially designed for measuring mainly mΩ and μΩ.

But I'm afraid we go OT. 

Wulf


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## manne (Aug 6, 2008)

Thanks for the usefull measurements SUBjohan, the poor efficiency on med and low looks like they use a improper way to dim, like simply a PIC (12f629 or something similar) that PWM the input voltage per MOSFET oder regulator's enable pin, can you confirm this? So maybe it should be possible to modify it to one mode?


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## TorchBoy (Aug 6, 2008)

manne said:


> ... the poor efficiency on med and low looks like they use a improper way to dim, ...


Add to that, I'm disappointed the medium isn't more logarithmically placed between the other two, but that wouldn't suit everyone either. It would be nice to be able to set them wherever.


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## Galiphrey (Aug 7, 2008)

That drop of efficiency for medium makes it look like the driver is loosing the same amount of power whether in medium or high mode (instead of loss being as a proportion of the mode).


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## spencer (Aug 9, 2008)

Mine has a memory function. Just got this driver and so far I like it.

Excellent work on the measurements SUBjohan


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## DocD (Aug 10, 2008)

So i've been reading the replys and it seem to be a positive towards these driver's but they are not very efficent on med and low ? in the real word does this shorten run time by converting power into heat ? how does it hold up against other drivers ? cheers DocD


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## StefanFS (Aug 10, 2008)

DocD said:


> So i've been reading the replys and it seem to be a positive towards these driver's but they are not very efficent on med and low ? in the real word does this shorten run time by converting power into heat ? how does it hold up against other drivers ? cheers DocD


 

They seem to work well enough. About efficiency on low & med real world runtimes needs to be performed in addition to the calculations made.

Stefan


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## mtnbkr1 (Aug 10, 2008)

Is there a recommended way to deal with the heat for this KD driver?


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## StefanFS (Aug 11, 2008)

~10 hours on low is what I got from six fresh eneloops in an mdocod battery holder in a 2D Mag. Not going to bother with medium, it drained the cells to ~0.9 Volt.


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## nightstalker101 (Aug 11, 2008)

mtnbkr1 said:


> Is there a recommended way to deal with the heat for this KD driver?


 
Ya, I'm not sure either, I ran mine for 15min on high and it was too hot to touch.


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## Galiphrey (Aug 11, 2008)

nightstalker101 said:


> Ya, I'm not sure either, I ran mine for 15min on high and it was too hot to touch.



Which area gets hot (or just the whole thing?) ?


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## nightstalker101 (Aug 11, 2008)

Galiphrey said:


> Which area gets hot (or just the whole thing?) ?


 
I'm not really sure which area heats up, however the whole thing ends up getting hot. I'm not sure if thats a bad thing, however its questionable.


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## Galiphrey (Aug 11, 2008)

>>-Auto-alarm towards high temperature,then switch to low mode automatically

I wonder how hot it has to get before the "auto-alarm" kicks in.


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## SUBjohan (Aug 12, 2008)

Galiphrey said:


> >>-Auto-alarm towards high temperature,then switch to low mode automatically
> 
> I wonder how hot it has to get before the "auto-alarm" kicks in.



I left mine running on high at 10V for 30mins and the auto-alarm did-not kick in. The driver was in free air.

Greetz Johan


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## Galiphrey (Aug 12, 2008)

SUBjohan said:


> I left mine running on high at 10V for 30mins and the auto-alarm did-not kick in. The driver was in free air.
> 
> Greetz Johan



I've received and installed mine now; I potted it to the underbelly of a P7 heatsink. It DOES "auto-alarm" after about 60 seconds of being on high. That is--it switches to the low mode. (I can begin to feel the heat on the outside of the flashlight body.) Then, apparently after cooling off for some seconds, it switches back to high again, and then repeats this later on... It does NOT do any of that after many minutes of medium-level. And if I'm reading your measurements right, the board itself produces the same amount of heat either way (high vs medium), so the difference then is the heat from the LED and through the heatsink, which (I assume) is being detected by the board. Unless I'm off the deep end now, then it seems like potting it to an LED heatsink the way I did doesn't cool the board, but actually heats it up... (?)


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## Packhorse (Aug 13, 2008)

What voltage are you running into it?


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## Galiphrey (Aug 13, 2008)

Packhorse said:


> What voltage are you running into it?



About 11.7 volts. Do you suppose it's more efficient at higher or lower input voltages?

Edit: ((My guess would be higher voltages))


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## SUBjohan (Aug 14, 2008)

Galiphrey said:


> About 11.7 volts. Do you suppose it's more efficient at higher or lower input voltages?
> 
> Edit: ((My guess would be higher voltages))



Nope, the higher the voltage the less efficient it gets.
And over 10V the Watt losses go up verry quick :sick2: 
I think (not measured :mecry that the Watt losses around 12V should be 3,5 Watts wich get turned into heat. 
At 6V the Watt losses are 2,1 Watts (I did measure this ) wich is 40% less heat.

Greetz Johan


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## milkyspit (Aug 14, 2008)

Galiphrey said:


> Unless I'm off the deep end now, then it seems like potting it to an LED heatsink the way I did doesn't cool the board, but actually heats it up... (?)




You're right, that's not a particularly good idea. (I learned the hard way some time back!)

As for heat, just taking a wild guess but one source might be the inductor itself, particularly if the inductor is a little less efficient than it could be. That's a lot of power passing through the inductor and things could easily get pretty toasty. Inductors are a pretty simple component, but the subtleties of forming a good one make their construction kind of a black art. The really good ones are few and far between, and typically cost a heck of a lot more than one would expect given the materials involved. :shrug:

Anyone have an extra piece or two of this board they might be willing to sell? I'll place an order with Kaidomain but would also like to grab a board or two in the near term to play with.


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## Packhorse (Aug 14, 2008)

OK I just made up a heat sink for my board. Its basicly a 1 inch x 1inch aluminium channel. I drilled a 9mm hole for the inductor to sit in and thermal pasted it in place.
I ran it for 5 minutes off a 12V battery (battery is a little flat and was at 12v) and ran 2 P7s in series off it.


High 1.9amps 22.8watt output 2.6 amps at 6.7v 17.42 watt or 76% efficient (it did drive a single P9 to 2.8amp)
Med .60 amps 7.2watt Output .77amps 3.12v 2.4watt 33% efficient.
Low .21 amps 2.52watt Output.24amps @1.8v .432watt 17% efficient.

Med and Low seem way way inefficent. perhaps I misread. I will remeasure again later. 

But the important thing is that I can run 2 P7s off of it at 12v & it did not go into heat protection mode. It got warm but not hot. :twothumbs


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## DocD (Aug 15, 2008)

So the way i'm understanding this is that the driver, has hope for being able to drive 2 P7's or may more? but as a single driver,ok on high and rubbish on med and low.


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## Phaserburn (Aug 15, 2008)

I know it's not as elegant a solution, but why not direct drive the P7 with three nimh D cells? No circuit losses or circuit heat issues to deal with. The nimh cells will hold voltage easily and provide around 2.8 - 3A to the emitter (with a vf of 3.25 - 3.5V), while giving excellent runtime to boot. I would think that dimming due to voltage drop in this scenario would be hard to detect by eye over the course of a long burn.


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## Packhorse (Aug 15, 2008)

For me, I would rather have full brightness for the whole of the run time. Plus the low volt warning.
The 2 lower power levels and thermal protection are just bonuses.
Not to mention the ability to run it off an existing 12volt battery pack.


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## 1 what (Aug 16, 2008)

Re; What gets hot and how to manage it.
Been following this but just too busy to contribute. Last night I wired up my board and used my calibrated finger to see what got hottest first (an ancient and sensitive measurement often used back in the days of "valves").
Result:





Since this side of the board has components of different heights and this is one of the low profile ones it makes sense to build it up to the top level and heat sink to it. A small piece of 3mm Al plus heatsink epoxy works well:





I then epoxied the "new flat profile" onto a dicast box I'm using for a project I'll publish in the next week or 2 and ran it for 15mins on hi with 8V in. There were no problems and I could still touch the other side of the driver at 15 mins.


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## Aircraft800 (Sep 16, 2008)

I have the newer version of this driver, there is two components where you have the spacer, is the heatsinking the same? Has anyone had any experience with the newer driver?

*Is this where I would need to heatsink?* 





*Is this the correct wiring? I can use either negative batt in?*


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## DocD (Sep 17, 2008)

Aircraft800 said:


> I have the newer version of this driver, there is two components where you have the spacer, is the heatsinking the same? Has anyone had any experience with the newer driver?
> 
> *Is this where I would need to heatsink?*
> 
> ...


do ypu have a link? cheers DocD


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## Aircraft800 (Sep 17, 2008)

DocD said:


> do ypu have a link? cheers DocD


http://www.kaidomain.com/ProductDetails.aspx?ProductId=1866
 
Quote Kaidomain: "Measures 19mm in diameter, and 8mm in height (Note: the diameter changes to 17mm since Aug.28th (shipping day)."

*I got the 17mm board, new design.*


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## mitch79 (Sep 18, 2008)

I'm interested to see if efficiency has improved on low/medium settings with this 17mm revision.
Just ordered one


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## Galiphrey (Sep 19, 2008)

mitch79 said:


> I'm interested to see if efficiency has improved on low/medium settings with this 17mm revision.
> Just ordered one



Let us know what you find!


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## CM (Sep 19, 2008)

SUBjohan said:


> Its is to good to be true. :mecry:
> But 83,5% is good enough for me
> 
> I have measured the thing and I have to say I like it.
> ...



If you look at the amount of power lost due to efficiency (or lack of it) if you look at the high setting, this is what I get from your spreadsheet:

Efficiency	Power loss
83.5%	2.1152
83.0%	2.0808
82.4%	2.1282
83.5%	2.008
81.3%	2.2855
80.8%	2.3628
79.8%	2.4992
79.0%	2.6214
78.7%	2.6901
77.8%	2.8201
76.6%	3.0174

At best efficiency of 83.5%, 2.1W of power is a lot of heat. 

For flashlight use, I think that the thinking has to change for the P7. I'm using a driver with ~92% efficiency and the heat generated due to inefficiency is 33% of that compared to the cheap driver with 83% efficiency. The converter gets very warm dissipating about 830 mW of power but it can be run without a heat sink safely. On the other hand, 2400 mW with the inefficient driver means an early demise for the driver. I think a driver with efficiencies in the low 80's driving a 12W load is a poor design but probably good enough for the masses.


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## mitch79 (Sep 20, 2008)

I agree CW. The problem is I have yet to find any other P7 driver that will fit in a "C" Mag powered by 2x Li-Ion.

I'm using one of Der Wichtel's drivers in my "D" mag but it won't physically fit in the smaller "C" tube.
If there's a better driver out there, the someone tell me please.


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## Der Wichtel (Sep 20, 2008)

I don't know if it works but you can file down the driver a little bit and put it in vertically


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## mitch79 (Sep 20, 2008)

Der Wichtel said:


> I don't know if it works but you can file down the driver a little bit and put it in vertically


There's not enough space between the switch and heatsink unfortunately.


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## Der Wichtel (Sep 20, 2008)

And what about putting the driver into the batterytube?

Then the driver have to be stablized with epoxy or something similar to handle the pressure made by the tailcapspring

I don't have a C Mag ( only a very old one with wider diameter), so it's just an idea.


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## Aircraft800 (Sep 20, 2008)

mitch79 said:


> I agree CW. The problem is I have yet to find any other P7 driver that will fit in a "C" Mag powered by 2x Li-Ion.
> 
> I'm using one of Der Wichtel's drivers in my "D" mag but it won't physically fit in the smaller "C" tube.
> If there's a better driver out there, the someone tell me please.


 
My problem exactly, I love the Small Form Factor of my 2C M*g, but the cheap 17mm buck driver that I have shuts down after 5min. use. 

I need to try to determine which components are getting hot, and try to heatsink them better, or someone needs to release a more efficient buck driver for the P7. The *Der Wichtel* one looks like the best one out, but I haven't seen anyone able to fit it between the H22A P7 heatsink and the M*g switch.


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## mitch79 (Sep 20, 2008)

Aircraft800 said:


> My problem exactly, I love the Small Form Factor of my 2C M*g, but the cheap 17mm buck driver that I have shuts down after 5min. use.


Oh bugger, that doesn't sound good. You've got the new 17mm type too.
I was hoping for an improvement over the old version. :thumbsdow


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## mitch79 (Sep 20, 2008)

Looking at Aircraft800's previous post, the area marked as getting hot looks like a pair of diodes. Now why would a pair of diodes be getting hot?

Methinks the full 2.8A current is passing through them and their being pushed right to the edge of their current handling ability.

The other question is what are they being used for? Is it just reverse polarity protection? If so I'd be happy to remove them.

Anyone here with more electronics experience than me who can nut out this circuit and tell us what's happening?

EDIT: Googling "SS34" indicates it's a 3A 40V Schottky diode. Hope that helps.

Cheers,

Mitch.


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## Aircraft800 (Sep 20, 2008)

mitch79 said:


> Looking at Aircraft800's previous post, the area marked as getting hot looks like a pair of diodes. Now why would a pair of diodes be getting hot?
> 
> Methinks the full 2.8A current is passing through them and their being pushed right to the edge of their current handling ability.
> 
> ...


 
Mitch,

You know what this means? I heatsinked the wrong components! :mecry:
I used a picture from another post to determine where to put it, no testing. Those diodes probably don't get hot at all, but I was anxious to assemble my light.

Before I disassemble my light, do you have a clew where the heat is generated? The IC? Which is it from those pictures?

Thanks for your help guys!!


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## Tohuwabohu (Sep 21, 2008)

mitch79 said:


> Looking at Aircraft800's previous post, the area marked as getting hot looks like a pair of diodes. Now why would a pair of diodes be getting hot?
> 
> Methinks the full 2.8A current is passing through them and their being pushed right to the edge of their current handling ability.
> 
> ...



The Schottky diode is an essential part of the buck converter.
At 3A the SS34 has a forward voltage of approximately 0.4V.
Approximately 0.4V * 2.5A = 1W of power are dissipated in a very small component, that's why it is getting so hot.
Putting 2 diods in parallel directly side by side doesn't make ich very much better.

Aircraft800,
I think you did heatsink the right components.


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## Northern Lights (Sep 21, 2008)

James35 said:


> Really? $12 is expensive in comparison to the the rest of the light? In my opinion, ALL of these driver boards I've found are a steal! Even the best D2DIM is only $20.
> 
> Let's say you were going to make a Mag 3D P7 light:
> $20 Mag 3D
> ...


 
I could not resist a reply, are you ever so correct!  And you can get good results, almost same discharge graph, with high capacity DD models too. I just built a P7 with a jack, 
1.5 D P7, Modes, Charging Jack, Electronic GID & more ,
and three more are coming that will sell for $225 and more. I own a P7 MTE I made DD with a five minute mod and it is almost as good in total output, very close, cost was < $50.

From a utilitarian point of view, the custom light gets a little more light out and runs longer. :shrug:


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## mitch79 (Sep 21, 2008)

Thanks for the explanation Tohuwabohu .

Having re-read this thread again I no longer believe the diodes are the problem.
1. Aircraft800 heatsinked the diodes and it still shuts down after 5 minutes.
2. A diode can't do that, it's just a semiconductor. 

The only thing I can think of that could cause that effect is a programmable IC with built in temperature monitoring.
Anyone care to guess which one's overheating?


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## kavvika (Sep 21, 2008)

Few questions before I purchase this driver and begin my first P7 mag-mod:

-If I place an order today, will I receive a driver with or without memory mode?If the answer is that all new drivers are shipped with memory mode, how would I acquire a driver *without* memory mode?​-Also, how should I solder the LED and power wires to bypass memory mode? I know it can be done on a few other drivers I have, such as DX #7880. Can the MCU be bypassed on this drive board?


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## mitch79 (Oct 13, 2008)

I received my KD P7 driver a couple of weeks ago. It's the newer 17mm version.
Like others here it overheats and cuts out to low mode after 3 minutes running on high. Power is 2x 18650 Li-Ion.

The diodes where getting way to hot, so tonight I changed them.
I used 2x 1N5822 40V 3A Schottky Diodes in parallel.

In Australia you can get them from DSE or Jaycar.

These axial lead diodes are physically much larger then the originals and will not fit on the PCB but it's not hard to solder them togeather and run a pair of short wires to them.

The result? I ran the light for 30min continuous on high before I turned it off. No problems.
Finally my 2C P7 Mag is a sucess. 

Sorry, no photos yet. I was in a hurry to assemble the light and I wasn't sure it would work in the first place.
I can now assure you it does :twothumbs


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## wquiles (Oct 13, 2008)

CM said:


> If you look at the amount of power lost due to efficiency (or lack of it) if you look at the high setting, this is what I get from your spreadsheet:
> 
> Efficiency	Power loss
> 83.5%	2.1152
> ...



+1. Glad I am not the only one to note that in terms of efficiency and wasted power, most all of these "new" drivers are simply terrible. Of course, the P7 is just bringing the worst out, given the 3Amp goal.

For now, I "still" like the D2DIM: although it is not a "regulated" driver, when using it with good LiIon cells for a nearly flat discharge, it gives me full dimming control at nearly 100% efficiency by using PWM.

Will


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## kevinm (Oct 13, 2008)

So the new one is 17mm...what's the new thickness from the board to the top of the inductor and total thickness? I'm looking for something 6mm or so.

Thanks,
Kevin


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## Packhorse (Oct 17, 2008)

I have 2 of these drivers in use.
The 1st is priving a single P7 from a 6 cell NiMh pack and works great

The second is driving 4 Q5. 2P2S 1400ma each driven off a 8 NiCd pack.
This one causes a lot of interference on my TV and my landlords radio. More so when on the high setting.
Any ideas on how to fix this (apart from replacement). Will a cap on the output help?


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## uhg_ (Oct 19, 2008)

FYI: Tried this driver with 2 resp. 3 P7s in series, using a slightly tired 12V 4A NiHm. 2S driven at the full 2.8A on the LED side; 3S driven at 2.0A with battery Vin dropping to just above 10V. Driver gets warm enough to need cooling but not more, I think, than a bit of alu and/or some potting can keep in check.

Haven't done any extended testing so proceed at your own risk. But this seems like a pretty OK driver, at least for my purposes.


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## herulach (Oct 21, 2008)

Do the new diodes require heatsinking? Does it just move the heating problem elsewhere?


mitch79 said:


> I received my KD P7 driver a couple of weeks ago. It's the newer 17mm version.
> Like others here it overheats and cuts out to low mode after 3 minutes running on high. Power is 2x 18650 Li-Ion.
> 
> The diodes where getting way to hot, so tonight I changed them.
> ...


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## mitch79 (Oct 23, 2008)

herulach said:


> Do the new diodes require heatsinking? Does it just move the heating problem elsewhere?


No, I haven't got any heatsinking on the driver or replacement diodes.
The centre contact of the driver is soldered directly to the positive contact on the Mag "C" switch. The driver sits in free air.
No overheating issues since I replaced the diodes even with 30min+ runs on high.


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## spencer (Oct 23, 2008)

My driver is basically dead. It now only has a high mode and it doesn't last there for long. It stays in high for about a minute then flickers back and forth from high to low. Very annoying.
What are my options for a P7 driver? I'm running it in a 2D Maglite with 2x lithium ions. Should I try and return my old one?


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## mitch79 (Oct 24, 2008)

spencer said:


> What are my options for a P7 driver? I'm running it in a 2D Maglite with 2x lithium ions. Should I try and return my old one?


For a "D" Mag I highly recommend Der Wichtel's P7 buck converter.
I have a couple myself. Well made, don't get hot and just plain work.


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## ambientmind (Nov 10, 2008)

has anyone figured out how to make this a single mode board? I'd like to use der witchel's board, but its just simply too large for my application. or are there any other boards out there this size that will put out at least 1.8A off of 2 li-ions? i've been going crazy looking for something, but i've had no luck. thanks!


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## Hill (Dec 16, 2008)

mitch79 said:


> For a "D" Mag I highly recommend Der Wichtel's P7 buck converter.
> I have a couple myself. Well made, don't get hot and just plain work.



Mitch,

Just saw your post. I am building a P7 in 3D host with DW's driver as well. Did you need to heatsink it? I will be using 9AA w/ NiMh cells = 10.8V

thanks,
Hill


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## Oznog (Dec 17, 2008)

Well at $12 you can't argue with it on a price basis... but...

I have been doing design in a similar field and there's just no way that tiny electrolytic can absorb the ripple at this current level. Capacitance itself is meaningless, its series resistance will be so high it will fail to stiffen the input/output and just heat up (which will give the capacitor an astoundingly short life). Even the tantalum might be in trouble but without measurement it'd be hard to say for sure.

Actually there's some ultra-low ESR ceramics that you could maybe mod it with to bring the ripple way way down. 

PIC16F629 has no ADC on it, so it probably can't do much to regulate its output.

On the Schottky- it may get hot, but that's not necessarily a problem. Oddly enough, they're actually MORE efficient when hot and they're not really prone to heat degradation as long as max junction temp is observed. So heatsinking won't help anything unless the diode is so hot it'll burn up the junction. Parallel diodes will help efficiency a little, but they won't share evenly. I think you're looking at efficiency gains on the order of 1% here, because you can only bring down the diode's Vf a little by doing this. Tohuwabohu hit on this the Vf may be 0.4v, but the LOWEST a huge Schottky could be would bring it down to a 0.3v drop. Which... isn't all that different. There are not really any higher current Schottky diodes in this size package and again it's not going to bring down Vf all that much.

Gotta say that even though there may be some dicey choices in this design (probably to serve you with a $12 driver), there are physical limitations even if we went with the best of components and still fit on a 17mm board.


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## Footleg (Jan 8, 2009)

Ordered 3 of these drivers http://www.kaidomain.com/ProductDetails.aspx?ProductId=1866 just before Christmas and 3 P7 LEDs http://www.dealextreme.com/details.dx/sku.12721 to build my first high power LED lights. My driver boards appear to be the ones with only a single diode. This is covered by a white rubbery block which I assume is heat conducting to allow the diode to be heat sinked as suggested by earlier posters in this thread.

Fired the first one up last night, with the LED (mounted on a metal disk) stuck onto an old Intel Celeron CPU heatsink. Damn bright, and the whole heat sink got too hot to touch after a couple of minutes.

So my questions: How do you manage the heat in your maglight conversions? Surely a maglight body is not such a good heat sink as a CPU heat sink? So how hot do they get? Do they keep your hands warm without needing gloves on cold Winter nights outside?

How hot is it safe to operate these LEDs at? Despite holding the driver foam block on the heat sink, the entire driver board quickly got too hot to touch as well!


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## Aircraft800 (Jan 8, 2009)

Footleg said:


> Ordered 3 of these drivers http://www.kaidomain.com/ProductDetails.aspx?ProductId=1866 just before Christmas and 3 P7 LEDs http://www.dealextreme.com/details.dx/sku.12721 to build my first high power LED lights. My driver boards appear to be the ones with only a single diode. This is covered by a white rubbery block which I assume is heat conducting to allow the diode to be heat sinked as suggested by earlier posters in this thread.
> 
> Fired the first one up last night, with the LED (mounted on a metal disk) stuck onto an old Intel Celeron CPU heatsink. Damn bright, and the whole heat sink got too hot to touch after a couple of minutes.
> 
> ...


 
I believe that piece of foam or rubber substance is just for shipping safety, preventing the top of the board from getting smashed in the mail sorter unless something has changed since my order. That piece wasn't even attached, just poked threw with the wires. Do you have a picture? It may help identify it.

The Maglite body will get hot, the only way I see to manage it, keep it turned down to mid-level unless needed.


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## Footleg (Jan 9, 2009)

Aircraft800 said:


> I believe that piece of foam or rubber substance is just for shipping safety, preventing the top of the board from getting smashed in the mail sorter unless something has changed since my order. That piece wasn't even attached, just poked threw with the wires. Do you have a picture? It may help identify it.



Sounds exactly like mine. It was a white rubbery block threaded onto one of the wires. I did think it seemed slow to transmit the heat from the board to my finger, although it did get hot eventually, so it is not completely insulating. I've started work on heat sinking the board with some RAM cooler heat sinks which I am cutting up to fit. I'll post pictures when I have got some. I chose these as they were cheap and included some heat sink thermal transfer permanent bonding strips in the pack. Cheaper than buying these separately from my local Maplin store anyway. I'm building into a box with a fair bit of free space, so size of the board is not a critical issue for me.


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## KnightRule (Apr 5, 2009)

I got the KD P7 Driver in March and it seem it's a new design from ones in September. There's no more thermal shutdown now. I ran it for 2 hours continuously, numerous times with no dimming in a Maglite 2c with no heatsink. It automatically shutoff when the voltage is too low (after 20 min of blinking). Although it get hot it work fine. I put a heatsink on it now though. I had an ealier version that runs on high for only 90 sec and then switch to medium (without heatsink).




[URL="http://www.postimage.org/image.php?v=gxFeyUS"]

[/URL]

It's available in 2 version: a 3 modes (high, med, low), and a 5 modes (low, med, high, strobe, sos). Both version looks exactly the same.


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## kevinm (Apr 6, 2009)

Mind posting a link to the new version driver board?

Thanks,
Kevin


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## KnightRule (Apr 7, 2009)

It's the same driver, just redesigned. Kaidomain didn't make a new page for the 5-mode. You don't which modes they will send you, so you might have to contact them directly and specifically state that you want the 3-modes or the 5 modes.


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## Ogg Vorbis (May 5, 2009)

I ordered a driver on 9-3-09, it's now sat happily in a 2C Mag. I checked the current in series with the LED and got 2.8A. I did find the board got very hot were the wopping great transistor was... so this is my solution!


















+ Arctic Alumina...

It was powering a MC-E 'till i broke it (long story) but is now feeding a DSWOI P7 and i haven't had any troubles yet...

Just thought i'd share...

Dan


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## Aircraft800 (May 5, 2009)

Wow Dan! That is an *exceptiona*l heatsink! Great design and clean work!

(Is that the 3 mode? If it holds up, I'll need one to replace the old one I have)


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## wquiles (May 5, 2009)

Aircraft800 said:


> Wow Dan! That is an *exceptiona*l heatsink! Great design and clean work!
> 
> (Is that the 3 mode? If it holds up, I'll need one to replace the old one I have)



+1. Really nice work 

Will


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## Ogg Vorbis (May 5, 2009)

Thanks guys :thumbsup:

You may notice there are two holes and a little bit that i had to file out from the hole for the inductor, simply put i miss guessed the position of one of the LED wires 

And yeah it's the 3-mode driver, works great. I know it's not the most efficient one out there, but it works on 2x18650 (what i wanted for the 2C), and fits in the 2C mag, oh and it doesn't break the bank! (quick note as well, the sample i recieved has memory and turns on at the last used level)

I though i'd run it a little while today, i left it for 10 min on high with no contact, got quite warm but seemed stable. Now i can't wait for my Eagletac M2 to arrive 

Dan


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## bstrickler (Jul 16, 2009)

Okay, I have one of these and installed it in my WF-1000L, but I have a problem

It's only single mode. It won't leave high mode (which is brighter than the original driver, which I fried, lol)
Also, it shuts off after only 30-60 seconds.

~Brian


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## phantom23 (Jul 16, 2009)

KnightRule said:


> I got the KD P7 Driver in March and it seem it's a new design from ones in September. There's no more thermal shutdown now. I ran it for 2 hours continuously, numerous times with no dimming in a Maglite 2c with no heatsink.





bstrickler said:


> Also, it shuts off after only 30-60 seconds.


Next change - thermal protection onboard again! And triggers even earlier...


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## bstrickler (Jul 16, 2009)

I bought the driver ~September-November of last year, when I was gonna make a P7 mag, but ran out of money before I could, so now its in the 1000L.

I hate the thermal protection circuit, because it cuts out so soon. What they need to do is just slap a heatsink plug on the driver like Ogg's heatsink, and charge like $1-2 more, so people don't have to worry about the damn heatsinking. Or just have it as an option, for the people who don't want it, because they're using it for something else.

Ogg, any chance you'll be willing to make more of those heatsinks? Just curious.

~Brian


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## xiejol (Jul 17, 2009)

> Ogg, any chance you'll be willing to make more of those heatsinks? Just curious.



Let me 2nd that.


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## bstrickler (Aug 4, 2009)

My need for it went out the window last week, when the driver blew. I wasn't even overdriving it! It was in my WF-1000L with 2 18650's, and the whole flashlight got hot as hell. I checked it out when I got back home, and sure as heck, several components were blown. 

List of blown parts:

3 SMD Resistors(?) marked R20 (looks like they literally blew the ends out. Board is semi-charred near them. WTF happened?)
2 Small diodes
+ a few other small components starting to bubble.

Other than that, it still works, but only for like 5 minutes before the thermal protection kicks in (idk if the LED is being DD with 8.4 volts or not, since I decided to rip the driver out. LED was happy at w/e power it was getting, though)

I would steer away from the 3-mode KD 5-15 volt driver. At $12, I would expect better quality. 

I'm going to replace the driver with ShiningBeams 17mm 8x7135 3-mode driver. The flashlight doesn't heat up at all when ghetto-rigging the flashlight to run off my Mag (3 Alkaline D's hooked to driver, and the driver hooked to the head and body of the WF-1000L. Hey, it works, though it's not pretty)

~Brian


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## Ogg Vorbis (Aug 4, 2009)

Sorry, not much chance of making any more heatsinks... as with most of the stuff i do it's a one off. Would love to be able to make more but i've change departments making it even harder to get on a machine :thumbsdow

But on a positive note my driver's still going strong :thumbsup:

Dan


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## dyannantuonojr (Sep 4, 2009)

Ogg Vorbis said:


> I ordered a driver on 9-3-09, it's now sat happily in a 2C Mag. I checked the current in series with the LED and got 2.8A. I did find the board got very hot were the wopping great transistor was... so this is my solution!
> 
> 
> 
> ...


My name is Daniel
I am new to the flash light modding genre and I have a question. Where do I solder my negative wire to the driver you have pictured above? Have you ever tried using 3 p7's in one flashlight using elliptical optics?
Thanks for your expertise.


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## gav6280 (Nov 26, 2009)

Has anyone figured out yet exactly which components are kicking out all the heat in the latest batch?


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## SmurfTacular (Apr 18, 2010)

Is there a way to remove the Med and Lo functions?
Or am I forced to cycle through each time I turn it on?


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## rufusbduck (Apr 23, 2010)

gav6280 said:


> Has anyone figured out yet exactly which components are kicking out all the heat in the latest batch?


 I've found that a good way to sink these boards is to pot them in heatsink paste (the setting kind) from either dx or kd and them make a sandwich of copper sheet that fits into a piece of copper pipe ~ 1/2" long then AA the slug to the flashlight body. I use these to drive 3 q5's in parallel(I know this is supposed to be a bad idea but it's been working for over a year now) in old vistalite bike light heads with additional copper added to the outside and copper nails drilled through and soldered as vias to aid in heat transfer. The lights never dim while riding and only heat up when I stop which is when I dim the light anyway. The stock switch in the lamp head works both as a momentary (normally closed) switch to change modes and full click to power on/off. I have the newer ones which do have memory. The power fet and the inductor on one side and the two ic's on the other should all be AAed to the heatsink. If you remove the positive contact you can solder a new vin+ to the other side and have all your wires on one side. This helps immensely for my purposes. If you have just a little more room, Georges Maxflex driver from Taskled works GREAT at pushing 4 epg r5's at 1.3 A and is about the size of a quarter. If you ran your mce/p7 2s2p it would be only slightly underdriven and mulltiple leds would be even more efficient.


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## TorchBoy (Apr 23, 2010)

rufusbduck said:


> The lights never dim while riding and only heat up when I stop which is when I dim the light anyway.


I just had the possibly crazy idea of using one of those fan-powered LED lights to control the dimming of a bike light. I wonder if that would work...


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## rufusbduck (Sep 19, 2010)

Does anyone know what the difference is between the 8566 kd driver and the 5296 kd driver besides $2.00? They seem to use the same info page. 
Thanks


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## Packhorse (May 7, 2011)

Has anyone tried running 3 (XML's) LED's in series off a 12v NuMh pack yet?

I have had very good results running a 7.4v load from one but the 10vf off 3 XMLs??????


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## djipe (May 17, 2012)

Hy !

2 years ago, I baught this driver (3 Amps for MCE) from KD :





Since 2 years, I supply it with 2 18650 (7,2 V)
And Now, I'm interested to supply it with 3 18650 (10,8 V). The specifications are not any more available on KD website 

Do anybody know the max voltage that we can supply this driver ?

In advance thanks


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## jpou (May 17, 2012)

are there any parts on back side? It might be risky to drive it with 10,8V because electrolytic 100uF cap is rated for 10V.


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## djipe (May 17, 2012)

Yes, theire is small componants (CMS) back side.

My driver seems to be the same than one of theses :
http://kaidomain.com/product/details.S007542
[URL="http://kaidomain.com/product/details.S006130"]http://kaidomain.com/product/details.S006130

So[/URL], I will try... And if it burn... I will know...
Next buy, I'd better save basics specifications


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