# PWM Soft-starter design discussion



## JimmyM (May 31, 2007)

I've been posting here and there about an idea I have for a PWM softstarter. So I figured I just consolidate the discussion.

There are plenty of bulbs that can stand higher voltages if the voltage is ramped up instead of just closing a switch. However the choices were pretty limited. You had to buy a regulator that offered soft-starting as a feature. The choices are AWRs Hotdriver and the rare as Hen's teeth PIR by winny. They both have their advantages (actual regulation) and disadvantages (limited power handling and cost).
I really just wanted a way to soft-start a really powreful incan. The hotdriver has ragged edge reliability and the PIR is complex.
So I figured a solution would be a PWM driver that ramps it's duty cycle from 0 to 100% over a period of time. That time needs to be adjustable from almost 0 seconds to about a second. The fact that the MOSFET is either full on or full off, means that the ramp up time isn't limited by the heat dissipation ability of the MOSFET. It will go from fully on to fully off in less than a microsecond.

My design is as follows.
A Micrel MIC1557 oscillator runs at about 1kHz producing a sawtooth wave. The voltage of the sawtooth varies from 1/3 of the operating voltage to 2/3. That signal is sent to a comparator that compares the sawtooth signal to the voltage determined by a voltage divider (2 resistors that go from + to -). If the voltage divider's voltage is 50% of the operating voltage, the comparator will turn on when the sawtooth is below that voltage and off when it's above. if you adjust the voltage divider you can control the percentage of time that the comparator's output is on.
A low voltage at the divider means low duty cycle, high voltage means high duty cycle. Now, remember that whole 1/3-2/3 thing from before? Well, if you adjust the voltage divider so that it's voltage is above 2/3 of the operating voltage, the comparator's output is on all the time.
If you hook that output to a MOSFET you now have a high current/low resistance switch that operates at 1kHz.
A perk of the 1/3-2/3 thing is that if you hook a capacitor to the comparator input, the voltage will ramp up itself when the light is turned on. Well, when you first turn the light in the capacitir starts charging very quickly. That's bad for soft-starting. BUT since the comparator won't even start switching on the MOSFET until the capacitor has charged to 1/3 of the operating voltage, the "ramp up" voltage is less steep, and therefore starts more gently. So instead of ramping up VERY quickly at first and then tapering off almost indefinitely. It's a lot more linear. That is good for soft-starting.

The parts list is as follows.
1 Micrel MIC1557 oscillator (produces the sawtooth wave)
1 Linear Technology LT1716 Comparator (turns sawtooth to square wave)
1 Texas Inst TPS2819 Mosfet driver (ensures the MOSFET switches hard and fast)
1 International Regulator IRLR7843 or IRF1324 MOSFET.
A few resistors and capacitors.

That adds up the ability to control the ramp up time almost indefinitely and cap the duty cycle at something less than 100%. So you can limit the output voltage to a percentage of the input voltage.

Total cost of electronic components is about $10. Believe it or not, the bare etched boards themselves could cost $20 a piece if I were to have them made.

So.... Thoughts?


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## LuxLuthor (May 31, 2007)

As much as I understand about this, and previous posts, it sounds like something very useful. Do you have a prototype of it tested?


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## Action (May 31, 2007)

I love the idea of a softstart, but I'm a bit fuzzy on if this can easily be integrated with a hotdriver or a newer/more reliable high voltage version of a hotdriver. Are you investigating this as an addon to a hotdriver or instead of a hotdriver?

I'm personally in the market for softstart and hotdriver type functionality in the 18-30V range all mounted on a Kiu, with icing too...

Of course if you ever get into a real, adjustable PWM at higher voltages and amperages, I'd be all over that sucker!


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## jimjones3630 (May 31, 2007)

Nice work! My three favorites: Cheap, availabe, and efficient.:thumbsup:


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## Bandgap (May 31, 2007)

You don't need so many components - there are plenty opamp/comparator PWM circuits. 

Like the top one of these. 

www.4qdtec.com/pwmmod.html

The non-linearity in the triangle wave makes no difference to the PWM output and your soft start cap can go on the input with a pot to control speed. 

At 1kHz, IMO, you will not need a gate driver chip as the mosfet will switch plenty fast enough and the slightly slower switching edges will prevent it becoming a radio transmitter. 

Steve


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## bfg9000 (May 31, 2007)

Action said:


> I love the idea of a softstart, but I'm a bit fuzzy on if this can easily be integrated with a hotdriver or a newer/more reliable high voltage version of a hotdriver. Are you investigating this as an addon to a hotdriver or instead of a hotdriver?


The hotdriver already has soft-start. You don't need to go through the trouble of implementing PWM just for soft start, but of course PWM would allow it to function as a regulator too.


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## JimmyM (May 31, 2007)

bfg9000 said:


> The hotdriver already has soft-start. You don't need to go through the trouble of implementing PWM just for soft start, but of course PWM would allow it to function as a regulator too.



Softstarting and regulation have nothing to do with each other. A linear softstart will burn up the MOSFET. A PWM driven MOSFETwon't burnup. PWM versus Linear, it's just a different mode of operation.
It would physically replace the HD, but only do soft-starting. It would have an almost unlimited power handling under 40 volts. The IRLR7843 works up to 30 volts (3.3 mOhm) while the IRF1324 is good to 24V (0.8 mOhm).

How about some of those simpler designs? Where can I find them? I thought 4 SOT-23 packages was pretty simple. The gate driver also has a voltage regulator built into it. It would serve double duty.


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## bfg9000 (Jun 1, 2007)

Was merely explaining to Action why you would not need this circuit with a hotdriver. But here's AWR's PWM-free soft-start only circuit and Burnt Retina's excellent one (too bad the schematic is gone; maybe PM him?). Willie Hunt seems to not believe soft-start actually extends bulb life when used with a regulator.


JimmyM said:


> That adds up the ability to control the ramp up time almost indefinitely and cap the duty cycle at something less than 100%. So you can limit the output voltage to a percentage of the input voltage.


 Sounds like most of the components for regulation are there to me, missing only a mechanism to increase duty cycle as input voltage falls.


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## JimmyM (Jun 1, 2007)

bfg9000 said:


> Was merely explaining to Action why you would not need this circuit with a hotdriver. But here's AWR's PWM-free soft-start only circuit and Burnt Retina's excellent one (too bad the schematic is gone; maybe PM him?). Willie Hunt seems to not believe soft-start actually extends bulb life when used with a regulator.
> Sounds like most of the components for regulation are there to me, missing only a mechanism to increase duty cycle as input voltage falls.


No problem. The PWM free soft-start would incinerate if used to start a powerful incan in more than few milliseconds. Even with regulation it only limits VOLTAGE. Voltage isn't necessary the killer, it's the giant current spike on startup. Now current regulation would be awesome.


The regulation is the tricky part. You have to smooth-out the voltage at the output so the regulator chip sees a smooth input. But you don't want to start hangin inductors and caps off of it just to smooth the few uA to the regulator. I'd have to build a suitable "sample" circuit.
That's step 2.


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## petrev (Jun 2, 2007)

Hi Jimmy 

Posted this elsewhere so re-posting in this more appropriate thread



petrev said:


> Hi Jimmy
> 
> 
> Been watching all these posts on the big bulbs here and in the Most Powerful thread and noting your comments on your PWM softstarter - so these are my thoughts / wishes . . .
> ...




Simple is Good

If the overall dimensions (diameter) can be kept small enough to fit in a C-Tube (C-Kiu diameter is way small) then this would no doubt also be helpful ! may be able to work a design to drop into a C tail ?

Cheers Pete


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## JimmyM (Jun 2, 2007)

My first goal will be to get it to fit under a D-Kiu. BUT, If I could build a double decker, 1 for oscillator/driver and an upper deck for the MOSFET itself. It could fit into the barrel of a C body.
The circuitry is components are super small. Other than the MOSFET, the biggest thing is a SOT-23 package.

I can't wait to get some time to do this. The frequency is pretty low, I shouldn't have ground-plane issues or other circuit trace black magic.


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## unnerv (Jul 12, 2007)

Any updates on this? Sounds interesting for my next hotwire build


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## JimmyM (Jul 12, 2007)

Yes actually. I was hesitant to post because I haven't bought the parts yet.

Design is final and tested. It incorporates a small voltage regulator to keep the control electronics at roughly 12 volts. That allows it to have a battery voltage of up to 24 volts with the IRF1324 MOSFET and up to 38 volts with an IRF2804 MOSFET.
My test set up was a 20A 13V bench supply running an Osram 64623 bulb.
Just tonight I tested it at ~50% duty cycle and let it run for about an hour. The MOSFET, an IRF1324, barely got warm at all. Then I tested it at about 95% duty, for another 30-40 minutes and it cooled off. At 100%, it runs at room temperature indefinitely. It soft starts over the course of about 0.5-0.75 seconds. It can be double or triple tapped. Something that would toast a hot driver. It does not have a low voltage cutout however.
Right now I'm building the PCB layout. A real pain in the A** since I don't have any design software.
The pain here is that I'll be etching the boards myself since I don't want to go to the expense of having them done professionally. I've done this before a few dozen times, it's just time consuming.
My goal is to keep it as "cheap" as possible. I'm hoping for $15-$20 each.
I'll be building all of them without MOSFETs then soldering in the MOSFET of choice of the buyer. 12-22 volts would select the IRF1324, 12-38 volts would selct the IRF2804. The 2804 is about $8 versus the 1324 at $5.
You can even bypass the on board regulator and use it from ~7.2V to 16V for soft-starting a 5761 or Mag85 if you want. However, since the gate of the MOSFET is driven by the exact battery voltage, the lower voltage applications results in a slightly higher MOSFET resistance. It shouldn't be an issue since the heaviest draw application in the 7.2 volt range is the 64275/5761 @ about 6.5-7 amps.
The trim pot on the board allows the maximum duty cycle to be set by the user. This is NOT a regulator, but you can limit the output by turning it down to a percentage of battery voltage.
From it's lowest setting, it will soft-start gently to ~50% duty cycle. As you turn it, you increase the duty cycle to which it gently soft-starts. At about 3/4 of full turn, it will soft-start gently (0.5-0.75 seconds) to 100%. As you turn it further, it just starts quicker. Cheap and simple. You could even mount an external potentiometer to allow external control of dimming.
Once I have a PCB design, I'll order the parts and build a few.




unnerv said:


> Any updates on this? Sounds interesting for my next hotwire build


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## jimjones3630 (Jul 12, 2007)

Excellant Jimmy


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## petrev (Jul 13, 2007)

Hi Jimmy

Sounds great - love the max. trim pot - just what we need to get the best from our Lions.

Anybody got a spare Mag-7C knocking around that they don't need ? 

Count me in . . .

Cheers Pete


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## sysadmn (Jul 13, 2007)

JimmyM said:


> Right now I'm building the PCB layout. A real pain in the A** since I don't have any design software.



No SW? Is this by choice? I know many of the packages have a learning curve, but the thought of using MS Paint....:eeew:

Here's a dated link, but a good starting point.

If the boards get complex, I've heard good things about Sparkfun, but haven't used them myself.


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## JimmyM (Jul 13, 2007)

Thanks for the tips. I got it done with Visio. I've got a multi-layer board layout and I only had to use one jumper. Bit of a pain in the a**, but it's done, including the drill markers for wires and mounting screws. Now I need to get some toner transfer materials. Anyone had any luck using a laser printer, glossy photo paper and an iron?

I just contacted 4pcb.com to get a copy of their software and give this a try the PROPER way.



sysadmn said:


> No SW? Is this by choice? I know many of the packages have a learning curve, but the thought of using MS Paint....:eeew:
> 
> Here's a dated link, but a good starting point.
> 
> If the boards get complex, I've heard good things about Sparkfun, but haven't used them myself.


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## unnerv (Jul 14, 2007)

sounds great! Please put me down for two. I'll be using a 16 cell nimh pack. Paypal Locked and Loaded


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## cnjl3 (Jul 14, 2007)

I'm in for two! Probably one of each Mosfet


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## sysadmn (Jul 17, 2007)

JimmyM said:


> Now I need to get some toner transfer materials. Anyone had any luck using a laser printer, glossy photo paper and an iron?


 
Yes, it actually worked better than I expected. Unfortunately, the "right" paper can be hard to find. I used google to find the most recent articles from people doing it at the time, and still bought 3 kinds of glossy paper before I found one I was happy with (fine lines).

Here's the first and best info I found:
http://www.fullnet.com/~tomg/gooteepc.htm


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## JimmyM (Jul 17, 2007)

Thanks. I'll have a look. It looks like it will be cheap enough to have the boards built. Which means more will be available. However, I want to use the toner transfer method to build a prototype or 2 to confirm functionality on that scale and the board design itself.



sysadmn said:


> Yes, it actually worked better than I expected. Unfortunately, the "right" paper can be hard to find. I used google to find the most recent articles from people doing it at the time, and still bought 3 kinds of glossy paper before I found one I was happy with (fine lines).
> 
> Here's the first and best info I found:
> http://www.fullnet.com/~tomg/gooteepc.htm


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## Bimmerboy (Jul 17, 2007)

JimmyM said:


> Anyone had any luck using a laser printer, glossy photo paper and an iron?



Semi-funny story this reminded me of. About a month ago, I was in Radio Shack for random parts, when walking in comes _the spitting image of AWR_! He went right to where the PCB etching kits were and grabbed one. My imagination immediately went wild, and started thinking Andrew went into hiding in NY, and needed to build more Hotdriver's for cash. So I put on the detective hat :tinfoil: and struck up a conversation directed toward finding out if it was him, without revealing my identity.

Turns out it wasn't him, but man... the resemblence was that close. Anyway, JimmyM, the AWR clone says the iron method works great!

BTW, I'm interested in this project for an 1185, then who knows what after that... so, definitely in for at least one. Good luck with the proto's!


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## JimmyM (Jul 17, 2007)

Too funny.
Glad to hear about the "iron method" maybe I'll get some photo paper tonight. Do I even need photo paper? Or would regular work too?
Hmm let's find out.



Bimmerboy said:


> Semi-funny story this reminded me of. About a month ago, I was in Radio Shack for random parts, when walking in comes _the spitting image of AWR_! ...
> Turns out it wasn't him, but man... the resemblence was that close. Anyway, JimmyM, the AWR clone says the iron method works great!
> 
> BTW, I'm interested in this project for an 1185, then who knows what after that... so, definitely in for at least one. Good luck with the proto's!


 
For the new C cell projects running around that use AWs Cs, I could build a softstarter that doesn't include the onboard voltage regulator (It's just for the PWM circuitry) and use a smaller MOSFET. I had been testing the soft starter using the smaller MOSFET but it got a little warm after running a 64623 at 14v for a while. So I switched to the IRF1324 bad boy. For a C body 5761 or Mag85 it would be perfect. Hmm I'll see what I can design for a C cell diameter.


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## JimmyM (Jul 20, 2007)

OK. I got some paper and did some printing. WOW these come out nice. I've also found good information on the etching process to reduce indercut. So I bought some carbide drill bits and a drill press for my Dremmel. Making boards this way is going to be too easy.
I can't wait to make LOTS of neat stuff.
Now I just need an O-scope.


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## LuxLuthor (Jul 20, 2007)

JimmyM said:


> Making boards this way is going to be too easy.



You are forgetting Murhpy's Law....and you are from BeanTown....home of Murphy's illustrative "Big Dig."


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## JimmyM (Jul 20, 2007)

C'mon now. No one EVER looked at he big dig and said "Sh*t, what could possibly go wrong?"



LuxLuthor said:


> You are forgetting Murhpy's Law....and you are from BeanTown....home of Murphy's illustrative "Big Dig."


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## LuxLuthor (Jul 21, 2007)

JimmyM said:


> C'mon now. No one EVER looked at he big dig and said "Sh*t, what could possibly go wrong?"



 Who would have thought...as you are driving through to meet your family at the airport....I wonder if they used the right glue for those heavy ceiling tiles?


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## JimmyM (Jul 21, 2007)

Do those things serve some other purpose OTHER than being a ceiling tile? I mean they weight like a 4 tons EACH.

Anyway. I digress.
I etched the boards and will be tinning and attaching a few components I do have as a test.


LuxLuthor said:


> Who would have thought...as you are driving through to meet your family at the airport....I wonder if they used the right glue for those heavy ceiling tiles?


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## cnjl3 (Jul 25, 2007)

Any news?


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## JimmyM (Jul 26, 2007)

I tinned the pads on the test boards. I received my carbide drill bits and got a Dremmel drill press. Works perfectly.
The TO-92 case voltage regultaor will juuuuust fit. It's the only through-hole component on the board. I already had some of the capacitors I needed in the right size so I tried soldering them. Worked perfectly. I would like to get some tiny swabs though. Maybe I'll order them when I place the order with Digikey.



cnjl3 said:


> Any news?


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## cnjl3 (Jul 26, 2007)

Great to hear that you are still working on it.
I do have a question about your PWM. 
When you switch it off will it be 'truly' off?
Most PWM's dont really turn off when you hit the kill switch.
The PIR and AW's soft start will drain your battery pack down which defeats the main advantage of Li-ions holding their charge for years.
I suppose a tail cap switch in addition to the regular MAG switch will do but I would prefer just one switch to worry about.


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## jimjones3630 (Jul 26, 2007)

Also glad to hear the work goes on.

I am getting valued experience-read as frustrated beyond belief-learning to solder itty bitty little things. 

Talked with local electronics shop about etching board (5 componates) and adviced to super glue components then solder direct. 

Will look into reference below. Thanks to who provided it.

"Here's the first and best info I found:"
http://www.fullnet.com/~tomg/gooteepc.htm


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## JimmyM (Jul 26, 2007)

It will be truly off. The mag switch controls the ONLY positive connection to the battery by ANY of the electronics. The PWM circuitry is completely dead.
The only current it will consume will be that caused by the leakage current of the OFF state of the MOSFET.
20 uA max at 25 deg C. That's 0.02 mA max. Anything with a MOSFET will leak current when off. That's the name of the game.



cnjl3 said:


> Great to hear that you are still working on it.
> I do have a question about your PWM.
> When you switch it off will it be 'truly' off?
> Most PWM's dont really turn off when you hit the kill switch.
> ...


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## unnerv (Aug 8, 2007)

Any updates?


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## JimmyM (Aug 8, 2007)

Not really. I just need to scrape together the money to buy parts. I got a letter from the IRS about 2 weeks go. Let's just say things are a little tight.
Left to do:
Buy parts, assemble prototype boards, test, etch a few dozen boards, assemble, sell.
I was going to have the boards made, but I'm kind-of rethinking it. We'll see.
The design works.
I've also got great progress on a true PWM regulator with softstart and adjustable voltage. Again, parts list is pretty reasonable, cost-wise.



unnerv said:


> Any updates?


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## unnerv (Aug 8, 2007)

I got some paypal funds waiting for an excuse to make their way too you.  I am building a 16 cell light soon and this would make the switching design much easier.


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## petrev (Aug 9, 2007)

Hi Jimmy,

Make mine a PWM-Regulator please. The softstarter with trim is a great start but the regulator sounds like Top-Banana - thanks for the update.

Can't wait . . .

Cheers Pete


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## Raoul_Duke (Aug 9, 2007)

petrev said:


> Hi Jimmy,
> 
> Make mine a PWM-Regulator please. The softstarter with trim is a great start but the regulator sounds like Top-Banana - thanks for the update.
> 
> ...




That sound pretty damn good to me.

I'd be up for a few of these aswell.

I know you probably dont want to do pre pay but I dont mind as it offsets the parts you need.


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## cnjl3 (Aug 9, 2007)

Nah! Pre-pay has such a bad ring to it.
How bout a 'deposit' or 'downpayment'?


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## sysadmn (Aug 11, 2007)

JimmyM said:


> The only current it will consume will be that caused by the leakage current of the OFF state of the MOSFET.
> 20 uA max at 25 deg C. That's 0.02 mA max. Anything with a MOSFET will leak current when off. That's the name of the game.



Cool. Some of the small embedded processors have extremely low current in sleep state - AVR's 1.8v parts advertise 100 nA leakage current and 650 nA sleep current (including oscillator and brownout detector).


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## JimmyM (Oct 1, 2007)

I just placed an order for parts.


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## JetskiMark (Oct 1, 2007)

JimmyM said:


> I just placed an order for parts.



Good news. I am hoping to be able to purchase 3 or 4 from you ASAP.

Regards,
Mark


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## Raoul_Duke (Oct 2, 2007)

Cool. I will be Up for a few of these aswell.


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## JimmyM (Oct 2, 2007)

Raoul_Duke said:


> Cool. I will be Up for a few of these aswell.


There are basically 2 options.
1) The IRF2804 MOSFET: if you EVER plan on having a battery voltage that exceeds 24V you need this option. It's good to 40V. It has 1.6 mOhms of resistance. At 10 amps, you'll drop 16 mV. Perfect for the hard driven 64458 or the 64655.
2) The IRF1324 MOSFET, If you NEVER plan on exceeding 24V, this is the MOSFET for you. It only has 0.8 mOhms of resistance. At 10 amps, you'll drop 8mV. The better choice for ragged edge 64623s at 16V
In either case, continuous load of 20A is no problem. Honestly though, you'll have more than 8mV drop in the physical contact from the battery to the positive switch connection.
The IRF2804 would just add $4 to the cost, which is yet to be determined.
$15-$20 is still my goal.
If you've got a L14K, let me know. I can build a unit just for that light with the proper amount of "overkill" on the MOSFET.


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## JetskiMark (Oct 2, 2007)

I have a LarryK14 that I run on 8S LiPos that I would like one for. I also have a LightForce 240 Blitz that I run on 10S LiPos with a 64663. Would it be possible to build a unit for this application? The cells hold about 40.4V under the 12.9A load.

Regards,
Mark


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## Raoul_Duke (Oct 2, 2007)

Well I have:

1 x 13 cell 2D 64623. Its pretty tight with the 13th cell in the tailcap, so not much room, but prehaps under the kiu heatsink. at the minute I have ceramic fiber in there, but would the components fit in there. Maybee just remove the switch alltogether.

3 x 6 C's with 4 emolis, and 64623 (and lower watt lamps)
Had my first instaflash on the 64623 a few days back, but thats because all the cells were close to 4.2V ( lots of room in this set up. 4 emoli is 280mm, and 6C cells are 300mm, the stock tailspring doesnt reach the cells, so I use the PR bulb hoder from the stock bulb hoder ontop of the spring to make up the difference in length at the moment , with a wire for resistance.)

1 x 7C ( with two more 7C's on the way) ready for 5 emoli's and 64458. Havent tried this yet still requires some modding. No room in here. have to take a few of the threads of the tailcap to get the tailcap to screw all the way down.

And a 6D that I also plan for 5 emoli and the 64458. Loads of space in there.

A low volt cut out would be nice for the emolis, as they dont like going under 3V and they dont dim noticably till they are at 3V ( resting voltage reading, unsure what that is under load) but not essential.

So none of them going above 24V, But you recomend the IRF2804 for the 64458? I thought 21V was bleeding edge for that?

I'm using stock switches with just the kiu socket, so the resistance of the switch is probably saving me instaflashes.

The D switches keep melting the contacts though. The C switches hold up better, but require a clean every now and then.

Oh, and I'm assuming that backing of the tailcap will stop any current leakage from the cells as long as the anodising holds up.
( "The only current it will consume will be that caused by the leakage current of the OFF state of the MOSFET.
20 uA max at 25 deg C. That's 0.02 mA max. Anything with a MOSFET will leak current when off. That's the name of the game")


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## MatajumotorS (Oct 2, 2007)

I did make one prototype too HERE 
and my controller have 
minimum parts, 
has no "leakage currents" because of controlling it via power supply
and has various modes of brightness and effects possible  not only slow start.
I will post some videos of my prototype in Maglite soon in this thread.


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## JimmyM (Oct 2, 2007)

Raoul_Duke said:


> 1 x 13 cell 2D 64623. Its pretty tight with the 13th cell in the tailcap, so not much room, but prehaps under the kiu heatsink. at the minute I have ceramic fiber in there, but would the components fit in there.


Yup. It'll fit under the KIU. Sounds like you've got a lot in the works.
softstarting the 64623 on 16.8V is right on the ragged edge, but it should hold if softstarted.
re: low volt cut-off. I know. I'd love to have one in there perhaps in rev2 when I build using a microcontroller.
The IRF1324 is good up to 24V absolutely no more. Batteries fresh off the charger may exceed that when running the '458 right on the edge.
The Mag switch, when properly modded, can deal with about 10A but still gets warm.
This curcuit bypasses the mag switch for all the high current stuff. The mag switch will only have to carry a few mA to turn the circuit on and off.


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## JimmyM (Oct 2, 2007)

JetskiMark said:


> I have a LarryK14 that I run on 8S LiPos that I would like one for. I also have a LightForce 240 Blitz that I run on 10S LiPos with a 64663. Would it be possible to build a unit for this application? The cells hold about 40.4V under the 12.9A load.
> 
> Regards,
> Mark


The circuit has a built in voltage regulator to power it's internal electronics. That regulator is good up to 80 volts. It would just be a matter of finding the proper MOSFET like the IRF3805 (55V, 2.6 mOhm). It costs about the same as the IRF2804. For the L14K, I would prefer using a different board layout to allow for better wiring to the MOSFET.
Your on-off switch would then just have to carry a few mA to control the circuitry. You could even have an exteranl potentiometer to allow for a full range of adjustment. A "brightness knob" if you will.


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## cnjl3 (Oct 2, 2007)

Well, I am definitely in for the IRF2804 MOSFET Softstart since i got a couple of the 64458 bulbs and I have been waiting for your Softstart so I can fire it up



JimmyM said:


> 1) The IRF2804 MOSFET: if you EVER plan on having a battery voltage that exceeds 24V you need this option. It's good to 40V. It has 1.6 mOhms of resistance. At 10 amps, you'll drop 16 mV. Perfect for the hard driven 64458 or the 64655.


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## JimmyM (Oct 13, 2007)

I received the electronics supply regulators. Nice little 80V units. I've decided that all soft starters will use the IRF2804s unless special ordered by the customer.
Ready to start etching once the other parts arrive.
Looking forward to a couple of beta units to be beat to hell by a couple of members I have in the que. Ideally, Lux or petrev will fail to find a combination under 40V that will cause this thing to bite the dust.
Theoretically, they should be able to throw 70A under any conditions under 40V at this thing.
Perhaps a 25-30V supply feeding 4 or 5 64458s in parallel using ~70% duty.
These are really torture type conditions, but hopefully we'll find a tested limit. The "danger zone" is about 75-80% duty cycle. Running a 64623 on 12V at that setting causes the MOSFET to get warmer than any other duty cyle setting. Anyway. Progress is being made.


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## JimmyM (Oct 13, 2007)

I also notice that there's not a lot of activity in here since I don't already have anyone's money. :thinking:


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## JetskiMark (Oct 13, 2007)

I'm glad to hear that progress is being made. I am definitely in for two for my LarryK14 and two for my 10S LiPo powered 64663. I also want at least two more for other projects.

Regards,
Mark


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## LuxLuthor (Oct 13, 2007)

JimmyM said:


> There are basically 2 options.
> 1) The *IRF2804 MOSFET*: if you EVER plan on having a battery voltage that exceeds 24V you need this option. It's good to 40V. It has 1.6 mOhms of resistance. At 10 amps, you'll drop 16 mV. Perfect for the hard driven 64458 or the 64655.
> 2) The IRF1324 MOSFET, If you NEVER plan on exceeding 24V, this is the MOSFET for you. It only has 0.8 mOhms of resistance. At 10 amps, you'll drop 8mV. The better choice for ragged edge 64623s at 16V
> In either case, continuous load of 20A is no problem. Honestly though, you'll have more than 8mV drop in the physical contact from the battery to the positive switch connection.
> ...



Jimmy, I think some of the lack of activity is because this is a pretty old topic, and it has not yet sounded like you had *everything *ready to go....and I was expecting you to start a *Custom Sales thread* about it. Two other things that may be affecting this is the AW D Driver project, with Regulated version coming soon....and it not being clear to me what this setup looks like in terms of size, where to install, when you are actually ready to go.

I can definitely say I would like to have at least 5 of these...maybe more. I don't see that the 0.8 milliOhm higher IRF2804 MOSFET or minor extra cost is any reason to go with the lower 1324.

I know I would put one in my Larry14K, another in my 21s x 1700mAh Elite AA's Elephant HyperBlaster 64655, another in 64458 DeathBlaster. Another in a code name: "Vaporizer" project I'm doing. :naughty:

Are you actually looking for payment now, or just commitments to buy? Can you give some of the size & physical appearance so we know best place to install?

Thank you sir!


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## jimjones3630 (Oct 14, 2007)

Would like to see this develope. It's hard for me to post here not having enough knowledge of how this works. For above discussion know more about the how it works. I know can work Winne did one as well as others. With adjustable voltage You build it and they will come.

looking forward to sending funds when you like.

Jim


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## JimmyM (Oct 14, 2007)

Really just kidding about the lack of activity. You're right, it is a rather old topic.
It looks almost exactly like AWRs Hotdriver. It installs exactly where the Hotdriver goes (under the base of a KIU D socket). I don't have pictures yet.
I'm not looking for commitments or payments ahead of time.
When I start a sales thread, I'll already have them built and I think I'll list them #1 through #20 (for example) and just let the buying begin. I think demand will far exceed supply initially because I want to keep the price down.

Also, for the Larry14K, I have a different unit in mind. :devil:
Dual 55V MOSFETs, A Max Duty Cycle trim pot, and an external pot to allow a "brightness knob" on outside of the lantern body.
I know some folks will point out that I don't need 2 MOSFETs, but my goal has always been absolute minimum resistance and heat.
Pics to come.


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## jimjones3630 (Oct 14, 2007)

Hope you make a few of the dual MOSFET heavy duty.

Some folks have gone beyond 24v running 250w. For myself the 4458 90w run at 18.2vbulb, is very satisfing and the form factor is as large as would want. Think you calculated at 21vbulb would get 233w so that's my goal. At 18.2vbulb now. Your PWM would make it so much easier with adjustable voltage.

Your design may share some simularities in application but it is not the samething. Yours is unique because you made it. I've looked under the hood of your work and it like looing at the working of a fine watch or some detailed piece of machinery.


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## LuxLuthor (Oct 14, 2007)

Sounds really exciting, Jimmy!


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## JimmyM (Oct 15, 2007)

jimjones3630 said:


> Hope you make a few of the dual MOSFET heavy duty.
> 
> Some folks have gone beyond 24v running 250w. For myself the 4458 90w run at 18.2vbulb, is very satisfing and the form factor is as large as would want. Think you calculated at 21vbulb would get 233w so that's my goal. At 18.2vbulb now. Your PWM would make it so much easier with adjustable voltage.
> 
> Your design may share some simularities in application but it is not the samething. Yours is unique because you made it. I've looked under the hood of your work and it like looing at the working of a fine watch or some detailed piece of machinery.


The Dual MOSFET will not fit into the Mag body. For pretty much ANYTHING you can put into a mag body, the single MOSFET will be more than enough. It should shrug off 15A like it's not there! The dual MOSFET unit is for 20+ amp, 600+W monsters. Each of these MOSFETs is rated for 150A continuous when properly heatsinked. The key there is "properly heatsinked". The MOSFET in the softstarter is hardly "properly heatsinked". So my gauge is... If I can hold it in my fingers after 15-20 minutes of running, it's good.


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## jimjones3630 (Oct 15, 2007)

The single MOSFET will work for me, every now and then think about Lantern size lights. Then take out the 64458 90w even with only 18.2vbulb and start grinning.


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## JimmyM (Oct 27, 2007)

I just received my oscilloscope and some of the parts.
After a few measurements made on the prototype circuit, I made an adjustment to one of the resistor values. I can now use a smaller MOSFET and it runs nice and cool.
Still waiting on the shipment of back ordered parts.


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## Raoul_Duke (Oct 27, 2007)

When you say smaller, smaller in what way, less power capability or size wize?

Going to be watching you like a hawk untill you put the goods up for sale :naughty:


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## JimmyM (Oct 27, 2007)

Smaller in size and capability. It's still good for 30V and 30+ amps. I was tesing it with 12V into a 64623 bulb. Starting and varying power up and down produced no discernable temperature increase. I'm going to make a 30+ minute run this morning to see what kind of heat I can make it produce. I'll run it at about 90+% so I combine the heat produced by ON resistance as well as that caused by ON/OFF transitions.

OK. That thing doesn't make any real heat. I just had it running for about 25-30 minutes and I could still touch it. In fact, it was hard to tell if it was warm at all.
This is going to make things a lot easier and slightly cheaper. Too bad I just bought 20 of the 40V/45A MOSFETs.
In any case, what ever MOSFET goes on the board can handle more power than you'll be able to fit into a Mag body.
64623, IRC65, 64458 no problem. The 64655 might over shoot 30V on a fresh pack (20*1.5V=30V), but the the first batch will have the 40V MOSFET anyway.


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## jimjones3630 (Oct 27, 2007)

Another innovation. Sounds like more progress and will take whatever time it takes. In fact, many improvements have developed. Bet, will not be massive returns for bug fix.


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## JimmyM (Oct 27, 2007)

jimjones3630 said:


> Another innovation. Sounds like more progress and will take whatever time it takes. In fact, many improvements have developed. Bet, will not be massive returns for bug fix.


Let's hope not!
The one's I release first will be the BIG MOSFET (IRF2804) because those are the one's I bought. The basic design works even better now. The next version, which will be add-on regulator compatible, I hope, will probably use the smaller MOSFET for space saving reasons. But we'll see. I don't want to start making a 24V version, a 40V version, then a 55V version, etc. All V1 softstarters will use the 40V mosfets.
Version 2 vision is a basic softstarter, but as an option, a piggy back regulator module could be added. So far just vision. I want to get version 1 out the door before I spend time on v2.


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## JetskiMark (Oct 27, 2007)

I am eagerly awaiting these. I hope the first batch does not sell out before I am able to purchase a few.

Regards,
Mark


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## Northern Lights (Oct 27, 2007)

JimmyM, I just went over an old PM about our soft start discussions, and I understand you idea better, as I said I can follow a lot about electronic design, I certainly cannot lead! I am waiting on your release too, I do not know if your design is what I am waiting for :thinking: but I know myself well enough that once you bring it out I will probably build something that needs it to work. I am having some problems right now with insta-flashing genuine Osram 64430  while some Tungsram and Chinese copies work ok with the same pack. That bulb with a 10.8 NiMh pack calculates to punch out over 2200 torch lumens in a 2D light! In that light with that pack, Vbulb at 10.6 blow the Osram bulbs but they hold at 10.4 Vbulb in the light. Currently I must charge the battery full then run the high-tech charger to discharge the pack to 10.35 Volts, all this bother over two tenths of a volt just to insure it works. Here is a perfect example of needing an adjustable driver. I am at the absolute edge of functionality here. 
I know from old posts of AWR that a 2D with Vbulb at 11.1 is supposed to be the stellar M85, (WA01185). These two examples of builds need a driver with adjustable output. 
I will be a person that always impractically runs my lights for max output and I will be tweaking any adjustments that I can get my hands on; whether it is needed or not.
Hey, its fun.:nana:


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## JimmyM (Oct 28, 2007)

Northern Lights said:


> I am waiting on your release too, I do not know if your design is what I am waiting for :thinking: but I know myself well enough that once you bring it out I will probably build something that needs it to work.


The soft-starter will have an adjustment to limit the percentage of Vbat that makes it to the lamp. That percentage is set by a potentiometer. For example: Your pack voltage is 10.8v. If you set the soft-starter to 90%, the effective voltage that the bulb will see is (10.8v *0.9) 9.72v. As the pack voltage decreases during use, the 90% figure doesn't change. So as Vbat falls to 9.6V, the effective voltage at the bulb drops to (9.6v*0.9) 8.64V.
Also, 9-10V is about as low as thing thing will work. I'm not using a MOSFET gate driver that boosts voltage to the MOSFET gate. I'll need to test lower run voltages to see what happens.

Now I just have to name these things. There's the HotDriver, the PIR. Some thing easy to search for and easy to use while posting so posts regarding it are easily found. Maybe JPSS. Jimmys PWM Soft-Starter.


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## JimmyM (Nov 5, 2007)

OK. A quick update.
I received the bulk of the parts I need to start building and prototyped the design using the new surface mount components. It works better than the full size part prototype. The previous design used about 7mA (max). The smaller components use 2.8mA (max) and ~0.7 mA at 100% duty. I need some slightly different resistor values and have ordered them. I'll start etching boards on Wednesday or Thursday of this week.
I should have enough parts to build 22 units.
Specifications:
Max voltage using included IRF2804 MOSFET: 40V
Max voltage using special ordered MOSFET: 80V
Maximum continuous current: 20A (Limiting factor is board traces. Special wiring during install can extend this to 40A)
Duty cycle range: ~50% to 100%
Switching frequency: 150-200Hz
Price: $20 plus shipping.
A special Larry14K version is coming.


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## petrev (Nov 5, 2007)

:twothumbs

Thanks for the update

How about *JM-SST* ( Trim )

then next gen. *JM-SSR* ( Regulated )

? :shrug:

Cheers Pete


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## JimmyM (Nov 5, 2007)

petrev said:


> :twothumbs
> 
> Thanks for the update
> 
> ...


I like it. I think I'll use it, if you don't mind.
Also, I was speaking with a friend that does electronics design for military applications. He had some good input for the PWM regulator.
3 chips + MOSFET, 20kHz, fully regulated goodness where Vbat = 8 to 80V.


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## Raoul_Duke (Nov 5, 2007)

JimmyM said:


> I like it. I think I'll use it, if you don't mind.
> Also, I was speaking with a friend that does electronics design for military applications. He had some good input for the PWM regulator.
> 3 chips + MOSFET, 20kHz, fully regulated goodness where Vbat = 8 to 80V.



Sweet.


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## petrev (Nov 5, 2007)

JimmyM said:


> I like it. I think I'll use it, if you don't mind.
> Also, I was speaking with a friend that does electronics design for military applications. He had some good input for the PWM regulator.
> 3 chips + MOSFET, 20kHz, fully regulated goodness where Vbat = 8 to 80V.



Hi

Use At Will.

Ditto - Sweet

Cheers Pete


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## jimjones3630 (Nov 5, 2007)

Way to go JimmyM!! I could have used a soft starter last week end. 

Have a wonderful mystery bulb labled 6v 30w small G4 pin. Hooked to kiu at bench and DMM to pins took it to 12.25vbat. I got so excited back it down to 6v took couple deep breaths, belt and braces Jimmy all the way to 14.3vbat and held few seconds and next increase blew.

The last little gem put in with 3xemoli 12.5vhot charged, very bright before it gave up the ghost. Should have waited couple of hours. 

Don't recall if you mentioned is this in [email protected] D, C, both? So, great job Jimmy.

Jim


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## JimmyM (Nov 5, 2007)

jimjones3630 said:


> Don't recall if you mentioned is this in [email protected] D, C, both? So, great job Jimmy.
> 
> Jim


It's a ~30mm board that fits under the D-KIU base.


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## mzzj (Nov 5, 2007)

JimmyM said:


> I've been posting here and there about an idea I have for a PWM softstarter. So I figured I just consolidate the discussion.
> 
> 
> 
> ...


Bit late probably but...

I would go for microcontroller instead of osc+comparator, cheaper and less parts. For example ATTINY45V in tssop-8 has 4 AD-converters, internal oscillator and more than enough memory for all the bells and whistles. Real regulation for example would be nice I guess. 

Boards: check out for example olimex.com ,you should be able to fit 15 boards to one eurocard so one board cost 33/15= 2,2usd


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## JimmyM (Nov 5, 2007)

mzzj said:


> Bit late probably but...
> 
> I would go for microcontroller instead of osc+comparator, cheaper and less parts. For example ATTINY45V in tssop-8 has 4 AD-converters, internal oscillator and more than enough memory for all the bells and whistles. Real regulation for example would be nice I guess.
> 
> Boards: check out for example olimex.com ,you should be able to fit 15 boards to one eurocard so one board cost 33/15= 2,2usd


Thanks, I appreciate the input. I simply have no experience what so ever with microcontrollers.
Perhaps I'll learn some day. Probably should.


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## LuxLuthor (Nov 6, 2007)

:thumbsup: Save me some!


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## JimmyM (Nov 8, 2007)

I just started some assembly work.
I masked a board and etched it. A little messed up. But mostly OK. I started soldering the components. I'll get more done tomorrow.


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## Bimmerboy (Nov 10, 2007)

Since this thread began, I've been here, lurking in the shadows... primarily because my Mag85 isn't built yet.  

Definitely looking forward to these!


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## JimmyM (Nov 10, 2007)

Received the final parts last night. The first beta unit is almost finished. A little snafu while etching, but I know what went wrong there. 2oz copper takes a while to etch. I put the etching bowl on the stove for a while to heat things up. Things progressed nicely after that. Today I have a wedding to go to out of town so today is shot. Soldering is becoming much easier now, even with 0603 packages. Flux is the key! 570 deg F on the soldering iron and just touch the component and pretinned pad. 1-2 seconds and all is done. Soldering the big MOSFET was a cinch with a different tip on the iron. 3-4 seconds.
I'm working from home next week, so I'll be able to etch several boards at once and hopefilly knock out several boards after testing the beta.


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## jimjones3630 (Nov 10, 2007)

Appreciate sharing the soldering techniques, you make it sound so easy and maybe with enough practice.




JimmyM said:


> Received the final parts last night. The first beta unit is almost finished. A little snafu while etching, but I know what went wrong there. 2oz copper takes a while to etch. I put the etching bowl on the stove for a while to heat things up. Things progressed nicely after that. Today I have a wedding to go to out of town so today is shot. Soldering is becoming much easier now, even with 0603 packages. Flux is the key! 570 deg F on the soldering iron and just touch the component and pretinned pad. 1-2 seconds and all is done. Soldering the big MOSFET was a cinch with a different tip on the iron. 3-4 seconds.
> I'm working from home next week, so I'll be able to etch several boards at once and hopefilly knock out several boards after testing the beta.


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## LuxLuthor (Nov 11, 2007)

I gave Jimmy all my tips that I have learned from soldering so far...right down to surface cleaning/prep/grinding, to the type of liquid flux, type of solder, having a small fan blow smoke away from you, larger magnifying lens with light, having selection of tips and soldering station with adequate heat, keeping tips clean, and I don't remember what else! LOL!


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## jimjones3630 (Nov 11, 2007)

I've seen Jimmy's soldering work in hand and he sure learned well from you lux

My metcal was such a good deal off ebay. wand and unit around $50-60, then got a handful of used tips for $10. just need practice.
jim



LuxLuthor said:


> I gave Jimmy all my tips that I have learned from soldering so far...right down to surface cleaning/prep/grinding, to the type of liquid flux, type of solder, having a small fan blow smoke away from you, larger magnifying lens with light, having selection of tips and soldering station with adequate heat, keeping tips clean, and I don't remember what else! LOL!


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## JimmyM (Nov 12, 2007)

I've soldered plenty in my pre-CPF life (gosh, how long ago that seems). Just nothing that darned small! The flux and marker worked perfectly.
OK An update.
I just completed a "beta" unit. It works EXACTLY as designed.
Lux, I'll be sending it to you to brutalize. The pot is smooth and runs a range of ~45% to 100% no sweat. The 'scope shows a real sharp turn on and off, so linear range heat is minimal. It runs at 155Hz.
Tomorrow I'll see about etching a full board worth of soft-starters.
LABOR INTENSIVE to build. Lemme tell ya.


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## LuxLuthor (Nov 12, 2007)

JimmyM said:


> I've soldered plenty in my pre-CPF life (gosh, how long ago that seems). Just nothing that darned small! The flux and marker worked perfectly.
> OK An update.
> I just completed a "beta" unit. It works EXACTLY as designed.
> Lux, I'll be sending it to you to brutalize. The pot is smooth and runs a range of ~45% to 100% no sweat. The 'scope shows a real sharp turn on and off, so linear range heat is minimal. It runs at 155Hz.




:thumbsup:



JimmyM said:


> Tomorrow I'll see about etching a full board worth of soft-starters. LABOR INTENSIVE to build. Lemme tell ya.



I can imagine after talking to AWR about what he uses for doing very small component soldering on those infamous Nano and BAM projects. After working on those, he considers his D Hotdriver as a walk in the park soldering.  I was freaking out fixing the current limiting setting on one of his HD's I got from someone.

Anyway, think how much you are learning...and deep down how you are letting your 'inner geek' shine brightly!


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## JimmyM (Nov 13, 2007)

LuxLuthor said:


> :thumbsup:
> 
> Anyway, think how much you are learning...and deep down how you are letting your 'inner geek' shine brightly!


Indeed.
Please PM me your mailing address.


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## JimmyM (Nov 19, 2007)

OK. The "beta" is off to LuxLuthor for testing. He and I have agreed on a testing regimen that should exceed pretty much any Mag bodied mod. I've etched and tinned 20 units and have about 1/2 of the vias soldered in. Once that's done, I'll begin soldering in the components.
I've run tests using a fixed 12V power supply, but Lux has a variable supply for better testing. Plus, I think "3rd party" testing carries more weight.


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## Action (Nov 19, 2007)

Oh baby! I can't wait to get my hands on one of these...


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## jimjones3630 (Nov 28, 2007)

Kind of like watching water boil, anxious anticipation.


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## Raoul_Duke (Nov 28, 2007)

jimjones3630 said:


> Kind of like watching water boil, anxious anticipation.



Your not wrong 

My heart nearly skipped a beat thinking I had misses the scrum when I saw a new post on this thread


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## JimmyM (Nov 28, 2007)

I know, I know. I'm the guilty party. Sorry. I didn't have time to do much work during the holidays. But over the last night or 2 I did a lot of soldering. These things are tedious to build. Solder a component on each board on a strip of 4 boards, then test each one, then move to the next strip of 4 boards. Oy vey. I should be able to finish them this weekend.

Don't worry, I'll post here with the location of the sales thread. Once things are all tested and ready to go. I have to get in touch with Sasha. I need to find out where I can post the sales thread. I had some conflicting interpretations of the rules that I needed her to clear up for me.


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## jimjones3630 (Nov 28, 2007)

Having tried my hand at micro surface mount soldering I do appreciate your hard work.

jim



JimmyM said:


> I know, I know. I'm the guilty party. Sorry. I didn't have time to do much work during the holidays. But over the last night or 2 I did a lot of soldering. These things are tedious to build. Solder a component on each board on a strip of 4 boards, then test each one, then move to the next strip of 4 boards. Oy vey. I should be able to finish them this weekend.
> 
> Don't worry, I'll post here with the location of the sales thread.


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## LuxLuthor (Nov 28, 2007)

JimmyM said:


> I know, I know. I'm the guilty party. Sorry. I didn't have time to do much work during the holidays. But over the last night or 2 I did a lot of soldering. These things are tedious to build. Solder a component on each board on a strip of 4 boards, then test each one, then move to the next strip of 4 boards. Oy vey. I should be able to finish them this weekend.
> 
> Don't worry, I'll post here with the location of the sales thread. Once things are all tested and ready to go. I have to get in touch with Sasha. I need to find out where I can post the sales thread. I had some conflicting interpretations of the rules that I needed her to clear up for me.



Jimmy, I updated you by PM on my testing. I asked Sasha about where to put my custom battery thread, and I don't have much question that yours should go in the same Custom B/S/T section.


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## JimmyM (Nov 28, 2007)

LuxLuthor said:


> Jimmy, I updated you by PM on my testing. I asked Sasha about where to put my custom battery thread, and I don't have much question that yours should go in the same Custom B/S/T section.


Thanks, Lux.


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## LuxLuthor (Nov 30, 2007)

All tests done that Jimmy wanted, and despite my best efforts to "break" his invention, it just kept working. 

Sending the results to him by email as requested first. It was a long night getting this all setup and doing series of tests at various settings...and I think my retinas are fried. Used two 64623 bulbs in parallel to crank some serious amps through this baby.

Here was my deluxe test bed, including Fluke temp readings on the 'Fet.


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## JimmyM (Nov 30, 2007)

To save Lux some effort (he's already done enough!) I'm posting his results here.
--------Lux---------
This worked great. I posted pix in the old CPF thread of my test bed setup. Soldered all connections & used 14 AWG to reduce resistance. I got bored with single bulb testing, so went with parallel 64623's which even with sunglasses still roasted my retinas. I'm sending you these details before crashing, as it was a long night doing this and a couple other things. I really tried to break it, but no problems or sign of anything not working. Only issue on the 2 bulb, higher settings was the increase heat...hard to know how much was being transferred from wires, and ambient heat radiation, even though I did shield bulbs from PCB when looking for peak temp. After longer run times, I did confirm by touching top and bottom of FET & wires going to bulb that it was getting hot (vs. hot air from bulbs heating up probe). 

I put each setting through more like 20-25 stop/starts using the switch. When on 2/3 max, I did another 10 on/off's as fast as I could push button after about 2 sec to reach peak...then off...then immediately back on. Never any problem. That 14G wire to the mofset is not touching the FET even though it may look like it. The Fluke thermister probe is touching the top of FET. There was no difference in estimated startup time, temp, amps, voltage beyond the 2/3 setting (full gave same results). The heat is a gradual increase, and my peak reading of 183°F was at the end of the last test of running for 15 mins straight. I had my Mastech 30V 20A dials on maximum, so these readings were what showed on its display. I have confirmed (with Fluke &/or Shunt) with my destructive bulb tests that these readings on Mastech are spot on with Fluke readings. 

All results are for the 2 parallel 64623 bulbs.

*Lowest Setting *


Time to maximum output - 3.5sec (approximate)
Voltage - 14.9V
Amps - 9.4A
Maximum Temp on FET - 123°F
*
1/3 Setting*


Time to maximum output - 3sec (approximate)
Voltage - 15.2V
Amps - 12.5A
Maximum Temp on FET - 135°F
*
2/3 & Full Settings
*

Time to maximum output - 2sec (approximate)
Voltage - 16.3V
Amps - 21A
Maximum Temp on FET - 153°F @ 5 mins; 171°F @ 9 mins; 183°F @ 11-15 mins
Let me know if there is anything else you have questions about, or if other tests....but I think this was a serious stress. That last test was using 342 Watts!!! 
--------END-------

I'm quite impressed actually. Impressed with how hot that MOSFET got. Normally this won't ever be an issue. The only bulb that draws over 20A is the one in an L14K. "Normally" a DeathBlaster level light draws ~12 amps.
I'll be doing a lot of work to finish and test the rest of the drivers this weekend.


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## JetskiMark (Nov 30, 2007)

Thank you JimmyM for all of the work designing and building this.

Thank you LuxLuthor for the comprehensive torture testing.

I am looking forward to buying a few and for the L14K version.

Regards,
Mark


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## JimmyM (Nov 30, 2007)

I'm talking to another CPFer about a 400W+ unit that uses 2 MOSFETs. This will be the L14K unit. In reality it should shug off 40 amps like it's nothing and work up to 55V. I need to do a little tweaking on the schematic.


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## JetskiMark (Dec 1, 2007)

JimmyM said:


> I'm talking to another CPFer about a 400W+ unit that uses 2 MOSFETs. This will be the L14K unit. In reality it should shug off 40 amps like it's nothing and work up to 55V. I need to do a little tweaking on the schematic.



Good news on this at up to 55V. My 8S LiPo L14K draws 600 watts according to my Astro Flight Super Whatt Meter and my 10S LiPo 64663 Blitz pulls over 500 watts.

You previously mentioned being able to have an external pot for dimming. This will be great. Will there just be holes in the PCB to solder wires to? If you could figure out how to make this unit regulated and adjustable, I would be willing to pay a premium price and I'm sure that many others would too.

Regards,
Mark


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## JimmyM (Dec 1, 2007)

JetskiMark said:


> Good news on this at up to 55V. My 8S LiPo L14K draws 600 watts according to my Astro Flight Super Whatt Meter and my 10S LiPo 64663 Blitz pulls over 500 watts.
> 
> You previously mentioned being able to have an external pot for dimming. This will be great. Will there just be holes in the PCB to solder wires to? If you could figure out how to make this unit regulated and adjustable, I would be willing to pay a premium price and I'm sure that many others would too.
> 
> ...


My current design has a provision for an external pot for dimming as well as a trim pot on the board for setting max duty cycle.
I'm working with a friend on a regulator design. The problem will be packaging it into a KIU socket. I just need to get these soft-starters out first. The Larry14K soft-start units will be next to build. I still have a couple of ideas to work out first before putting a prototype regulator together.


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## LuxLuthor (Dec 1, 2007)

JetskiMark said:


> Good news on this at up to 55V. My 8S LiPo L14K draws 600 watts according to my Astro Flight Super Whatt Meter and my 10S LiPo *64663 Blitz pulls over 500 watts*.



 Holy Cannoli !


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## JimmyM (Dec 2, 2007)

I wanna see beamshot comparisons with a big HID. Fog must actually evaporate in front of this light!


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## JetskiMark (Dec 2, 2007)

The only HID I have is a Power On Board 35W. My L14K absolutely blows it away. The 64663 running 39.4Vbulb in the 9" reflector of the Light Force 240 Blitz easily out-throws the Q4559X in the L14K.

I witnessed a L14K dominating a Barn Burner at the 3/17/07 LA Flashapalooza. It was the first time I had seen either of these lights in person and they are impressive. I started planning my L14K build that night.

I am looking forward to running a MOSFET in these lights and being able to use the stock switches again. A regulated soft-starter with an adjustable low voltage cutoff for LiPos (hint, hint) would be the ultimate.

Regards,
Mark


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## JimmyM (Dec 2, 2007)

JetskiMark said:


> I am looking forward to running a MOSFET in these lights and being able to use the stock switches again. A regulated soft-starter with an adjustable low voltage cutoff for LiPos (hint, hint) would be the ultimate.
> 
> Regards,
> Mark


I know. I know. Regulation with low-volt cut-off. The problem with a low-volt cut-off is that it takes proper calibration before application of full voltage. AWR's low-volt shut down is built into the chip he uses. It shuts down when the feedback voltage drops 8% below it's built in reference. He then uses the "power OK" output pin to shutdown the regulator. That's a problem when using PWM because the input voltage can be more than 2 times the output. For example, if you have a 20V pack running a 10V bulb, the pack voltage can drop dangerously low way before the feedback voltage drops at all. That would only happen when the pack voltage drops below 10V. You have to monitor the pack voltage itself. If you have a 10S LiPo pack, it has a peak voltage of 42 volts, 37V nominal, and a shut off of 30V. You can easily use a 24V bulb, but want it to shut down based on pack voltage not output voltage sag. The real problem is having a wide range PWM regulator with low-volt shut off. If you said build me an adjustable PWM regulator with low-voltage shut down for my 10S L14K, I'd say "sure let me put a schematic together". The L14K has some physical room to work with. But if you want to have it work over a voltage range of 10-80V and fit under a KIU socket, I'd have to say "let me work on that".
All is not lost. I have a few potential designs that do include low-volt shutdown. You can adjust the cut-off and cut-in voltages but component count increases. A PIC would be best for that, but I have exactly zero PIC knowledge. If the KIU base were just taller, I'd be in great shape.


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## twosouls2gether (Dec 3, 2007)

JimmyM said:


> I know. I know. Regulation with low-volt cut-off. The problem with a low-volt cut-off is that it takes proper calibration before application of full voltage. AWR's low-volt shut down is built into the chip he uses. It shuts down when the feedback voltage drops 8% below it's built in reference. He then uses the "power OK" output pin to shutdown the regulator. That's a problem when using PWM because the input voltage can be more than 2 times the output. For example, if you have a 20V pack running a 10V bulb, the pack voltage can drop dangerously low way before the feedback voltage drops at all. That would only happen when the pack voltage drops below 10V. You have to monitor the pack voltage itself. If you have a 10S LiPo pack, it has a peak voltage of 42 volts, 37V nominal, and a shut off of 30V. You can easily use a 24V bulb, but want it to shut down based on pack voltage not output voltage sag. The real problem is having a wide range PWM regulator with low-volt shut off. If you said build me an adjustable PWM regulator with low-voltage shut down for my 10S L14K, I'd say "sure let me put a schematic together". The L14K has some physical room to work with. But if you want to have it work over a voltage range of 10-80V and fit under a KIU socket, I'd have to say "let me work on that".
> All is not lost. I have a few potential designs that do include low-volt shutdown. You can adjust the cut-off and cut-in voltages but component count increases. A PIC would be best for that, but I have exactly zero PIC knowledge. If the KIU base were just taller, I'd be in great shape.



You know right from the start of this, and other threads I kind of always was wondering why not use a PIC or AVR (I only have experiance with PIC's, though nothing besides tinkering) instead. You would most likely need a small regulator (or high voltage PIC, I know they make them but no experiance), mosfet and of course the PIC. Program whatever you like into them, and they can do PWM via software or hardware. Could do something like a low voltage cutoff with a resistor voltage divider and on board comparator/AD sampling, maybe even one resistor a trim pot to adjust the cutoff within a range. You could even get those irritating SOS functions and whatever else you want into it in code. Now, I admit I haven't built any incand. yet, but I certainly want to, just no money right now... and the roommate's are moving out so rent is doubling, and Christmas... ugh. Am I way off here on this matter? Not knocking the work done here, I usually half finish a project and then it goes on the back burner so I give a :thumbsup: for getting it this far.

Oh yeah, btw I originally was going to post to say in regards to the time consuming soldering, maybe try reflow soldering. You can do it with a toaster oven (even a griddle I guess, the link was dead though). Do a little work with some solder paste, throw a whole batch (probably quite a few) in, and wait. VOLIA! Here's a couple links I found searching for reflow soldering.

http://www.instructables.com/id/Toaster-Oven-Reflow-Soldering-BGA/
http://www.seattlerobotics.org/encoder/200006/oven_art.htm

I found these surfing long ago, but never tried it. Looks easy enough, just wonder if the components can take it?

Rob

EDIT: I was curious, looks like on the high voltage parts from Microchip you can have ANY voltage you want and simply limit the current with an external resistor. So now the parts count would be PIC, resistor, MOSFET, and probably want the all important bypass capacitor (I ALWAYS forget those). PIC'S are $0.71 in bulk, or about a $1 in low low quantities, and looking at the PIC12's are only 8pin in whatever size you want.


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## Raoul_Duke (Dec 3, 2007)

JimmyM said:


> If the KIU base were just taller, I'd be in great shape.



Well, We will have to get some longer kiu bases made then, can't be harder than designing these cuircuits. Or cut away at the switch internals.

I'd be just as happy to loose the whole mag switch, and just put a different, smaller, switch in place, if it meant we could have all the bits required.

The switch housing is only a way of retaining the socket, I'm sure we could have an empty pipe that has a base to attach a kiu socket on, and a hole for a switch and grub screw, made easy enough, and then just fill it with components.

Probably enough room for some ceramic insulation, and reflective top to attach the kiu to would be good for IR aswell, to try to protect the cuircuits and cells a bit.


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## JimmyM (Dec 3, 2007)

Raoul_Duke said:


> Well, We will have to get some longer kiu bases made then, can't be harder than designing these cuircuits. Or cut away at the switch internals.
> 
> I'd be just as happy to loose the whole mag switch, and just put a different, smaller, switch in place, if it meant we could have all the bits required.
> 
> ...


 
If the KIU were just made deeper. There's a pedestal in the middle. If the entire thing were as high as the pedestal, that would be a lot better. I could then use a "sandwhich" style. There is already an entire switch replacement that does PWM dimming (AW's) and soon he'll have the regulator. My goal was to do PWM cheaper and simpler. I really don't want to start building new switch bodies. I have neither the time nor facilities for that kind of thing. To get everything on one board for a regulator I'll probably have to switch to a smaller MOSFET which will redude power handling, however the revised design would use a high side MOSFET driver which switches faster thus increasing power handling. Only experimentation will prove the results. So I'll finish the soft-starters that I have components for and then start on a regulator design.


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## JimmyM (Dec 3, 2007)

Update:
I've got 9 JM-SSTs built and tested. 8 regular ones and a custom. 2 of those are spoken for. I expected my order of POTs to be delivered already but they're on back order at mouser.com, so I found a comparable replacement and ordered them from Digikey. They should arrive this week.
Due to the cost and time involved in making these (it takes a LOT of etchant to etch a 6"x9" 2oz copper board on both sides) I'm going to have to raise the price to $25 each. Sorry for this. I was hoping to hit the $20 mark. Maybe if I can get the boards mass produced.


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## JimmyM (Dec 3, 2007)

The first 7 are up for sale.

https://www.candlepowerforums.com/threads/181866


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## petrev (Dec 3, 2007)

JimmyM said:


> Update:
> I've got 9 JM-SSTs built and tested. 8 regular ones and a custom. 2 of those are spoken for. I expected my order of POTs to be delivered already but they're on back order at mouser.com, so I found a comparable replacement and ordered them from Digikey. They should arrive this week.
> Due to the cost and time involved in making these (it takes a LOT of etchant to etch a 6"x9" 2oz copper board on both sides) I'm going to have to raise the price to $25 each. Sorry for this. I was hoping to hit the $20 mark. Maybe if I can get the boards mass produced.


 
Hi Jimmy,

Kiu did actually change the design slightly once already - he deepened the internal space so that AWR's HD would fit (more easily). If the top were machined to the pillar height and internal space expanded to match, then the socket mounting posts would need to have the screw threads shortened (by ~3.3mm) to avoid intrusion and the long mounting screws would need to be lengthened similarly.

Not a massively difficult exercise that maybe Kiu would consider ! ! !

Or (Kludge) you can cut off the pillar with a hacksaw and shorten the mounting posts ! and fit a small spacer ring or such like with the afore mentioned longer screws for mounting ! ! !

Great work on JM-SST and the future . . .

Thanks
Pete


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## R11GS (Dec 3, 2007)

I've been giving lots of thoughts to some PWM designs for both incandescent and LED's. I've given a lot of thought to both digital and analog approaches. I've got some really good ideas for some converters that do a good job of working at similar input and output voltages instead of just plain buck or boost. Be cautious going down the pure digital approach with low cost micros. They can run into some speed limitations particularly if they are handling the feedback compensation. Although for lights, you can just do a very slow loop and insure it doesn't overdrive or go into low speed oscillations with code.

For me, a purely analog approach is just plain easier. I don't need any development tools I don't already have and even though I can write code, I don't do it as a practice and so it's easier for me to develop [even complex] analog designs than to write code. Then a digikey order and I've got a proto. When I finally take the PCB step, we have suppliers that do proto PCB's (no mask or silkscreen) for cheap.

But there are pros and cons to both pure digital and pure analog approaches and I see the value in using a micro. I've got some thoughts about a mixed approach too that might really be a great way to go.


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## JimmyM (Dec 11, 2007)

More JM-SSTs are ready to here...
https://www.candlepowerforums.com/posts/2249552#post2249552


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## JimmyM (Dec 11, 2007)

Oops. wrong thread.


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## Jenova (Dec 11, 2007)

do we have any offical pictures of the model apart from lux's test rig ?


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## JimmyM (Dec 12, 2007)

Jenova said:


> do we have any offical pictures of the model apart from lux's test rig ?


 
I just updated the sales thread with a picture.


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## Action (Dec 12, 2007)

Thanks for the pics. Just a few quick questions.

I'm assuming that the trim pot is the very small square item shown on the upper right hand side of the connection diagram?

Would you happen to have any pics of it on a Kiu? Not having installed anything under a Kiu, I'm having some difficulty figuring out how to adjust the pot after installation...

Is the trim pot detented for 1/3, 2/3, and full or does it offer slight changes across its entire range?

Would there possibly be any way to get this preinstalled on a Kiu?


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## JimmyM (Dec 12, 2007)

Action said:


> Thanks for the pics. Just a few quick questions.
> 
> I'm assuming that the trim pot is the very small square item shown on the upper right hand side of the connection diagram?
> 
> ...


 
You are correct. That's the adjustment pot. There are no dentents. I installed one for another CPFer just a few days ago. I KNEW I should have taken pictures. Before final installation, I drilled a hole in the top of the KIU base for adjustment after installation.
I suppose I could install one for you. You'd have to ship me your switch and KIU first. The post office might charge more for shipping the bulkier item though.


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## JimmyM (Dec 12, 2007)

I've had a schematic for a Larry14K driver for some time now. Last night I bread boarded it to see if it will work. A few changes later. it works great. The main difference between this and the JM-SST is that there will be 2 60V MOSFETs and a MOSFET gate driver. These big MOSFETs have appreciable gate capacitance that causes them to turn on slower using just a pullup resistor. The MOSFET driver I used applies full voltage (11.5V internally) to the gate to turn it on. I actually had to add resistance to keep it from pulling too large a current spike from the onboard electronics. Now the 2 MOSFETs turn on almost instantaneously. The slightly slower turn on in the JM-SST is responsible for most of the heat that Lux Luthor measured. This L14K version will make less heat. It should easily be capable of 60+ Amps at 60V. I'm working on the PCB schematic now. It will have an onboard POT as well as a place to wire in a second POT for external brightness control. Brightness will be continuously variable over the entire adjustment range.

I need some help, however. I need someone with a Larry14K to open up their light and tell me where this thing will be mounted and how large it can be. Pictures would be helpful. Thickness is fixed by component height and will be about 7-8mm thick.


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## JetskiMark (Dec 13, 2007)

Good news on the design progress. Size should not be much of a concern. The area under the battery compartment is 58mm wide, about 30mm high and about 90mm between the posts.

I took this picture when I initially built it. Those measurements are what I could get without taking it apart. The 58mm width is exact. The other two are approximate but there is plenty of room.

I would like to add a digital panel meter to this light.

I have not yet decided on the exact model. Most of them require a 5V power supply. Would that be possible to incorporate into the design?

Regards,
Mark


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## JimmyM (Dec 13, 2007)

Thanks for the pix. That helps alot.
You mean you'd want a 5V output?
What's the open circuit voltage on a fresh pack?


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## JetskiMark (Dec 13, 2007)

Yes, a 5V output. Open circuit on this light is 33.6V (8S LiPo). 42V on my LightForce Blitz (10S LiPo).

Regards,
Mark


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## Action (Dec 13, 2007)

JimmyM said:


> You are correct. That's the adjustment pot. There are no dentents. I installed one for another CPFer just a few days ago. I KNEW I should have taken pictures. Before final installation, I drilled a hole in the top of the KIU base for adjustment after installation.
> I suppose I could install one for you. You'd have to ship me your switch and KIU first. The post office might charge more for shipping the bulkier item though.



Can I just send you a couple of Kiu'ed switches for install and then you could let me know about the extra that I would owe you?


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## cnjl3 (Dec 14, 2007)

I was reading your remark below about a deeper KIU alumn base and I have always wondered why not just use the bulb posts or pedestals underneath the KIU base for some additional height (they could even be trimmed/stacked to whatever height you needed) and yeah i know that bulb height would dictate how much height you could get away with. Hell, you could even file the center pedestal off and mount the KIU upside down with longer 3mm bolts and the sky is the limit. Either method would give you additional room for your circuit "sandwhich" Softstart, regulator, low voltage cutoff, fuel guage? or whatever else you can dream up.



JimmyM said:


> If the KIU were just made deeper. There's a pedestal in the middle. If the entire thing were as high as the pedestal, that would be a lot better. I could then use a "sandwhich" style. There is already an entire switch replacement that does PWM dimming (AW's) and soon he'll have the regulator. My goal was to do PWM cheaper and simpler. I really don't want to start building new switch bodies. I have neither the time nor facilities for that kind of thing. To get everything on one board for a regulator I'll probably have to switch to a smaller MOSFET which will redude power handling, however the revised design would use a high side MOSFET driver which switches faster thus increasing power handling. Only experimentation will prove the results. So I'll finish the soft-starters that I have components for and then start on a regulator design.


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## JimmyM (Dec 14, 2007)

I don't know whay I didn't think of that. Hell, I could just cut off the lower cylinder part of the base, leaving the pedestal and disc part. That would give me a few more millimeters of diameter as well. It would just be more difficult for the everyday modder to do. It would require some use of a hacksaw and file. The "spacers" could be small bore aluminum tube that come with the board when purchased.
Carlos, well played, sir. Well played.



cnjl3 said:


> I was reading your remark below about a deeper KIU alumn base and I have always wondered why not just use the bulb posts or pedestals underneath the KIU base for some additional height (they could even be trimmed/stacked to whatever height you needed) and yeah i know that bulb height would dictate how much height you could get away with. Hell, you could even file the center pedestal off and mount the KIU upside down with longer 3mm bolts and the sky is the limit. Either method would give you additional room for your circuit "sandwhich" Softstart, regulator, low voltage cutoff, fuel guage? or whatever else you can dream up.


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## JimmyM (Dec 14, 2007)

Sure, why not. I'm away all next week. So I couldn't get to it until the week between X-mas and new year's, but sure.


Action said:


> Can I just send you a couple of Kiu'ed switches for install and then you could let me know about the extra that I would owe you?


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## JimmyM (Dec 14, 2007)

JetskiMark said:


> Yes, a 5V output. Open circuit on this light is 33.6V (8S LiPo). 42V on my LightForce Blitz (10S LiPo).
> 
> Regards,
> Mark


The electronics that I've selected for the "internals" of the soft starter are good up to 80V, the MOSFETs are good to 60V. I looked at a couple of panel meters, they require about 50mA @ 5V. The 80V regulator I use can only do 20 mA. I could just build the board accomodate the 5V regulated output (LM7805) that can work with up to 40V and leave it off the board for the higher voltage units. It should only cost an additional few bucks.
I like it. After my latest experimental changes I have to change the PCB design anyway.
OK, then. I'll incorporate the traces for an onboard 5V regulator and leave it as an option to include the regulator chip if you run the unit under 40V.
Sound like a plan?


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