# Mag Switch Resistance Fix.. 1/6th stock!



## andrewwynn (Nov 29, 2005)

Ok.. too busy with a bazillion things to get to this sooner but here goes.. 

The step-by-step pictures are here

some highlights..






new ground wire.. bypassing the sliding contact.. Important note.. the little circular ring.. now i actually make a whole loop back to itself and solder so there are doubled-up wires coming off.. 1/2 the resistance and double the strength.. it is absolutely necessary for that to be soldered back to itself so it does not separate when tightening the screw.. or the wheel will no longer roll. 

I recently measured an old magswitch to have 18 to 100 ohms.. not miliohms.. OHMS!.. and as a testimony to Pro-Gold.. i put in 2 drops and worked it in and got it down to 6 or 8 miliohms in 20 seconds! nonetheless.. since it is the main part that fails.. i shorted it out with a wire!.. i actually cut out the slider so it can't short out with the new insides.

(resistance is now 1.43 miliohm)... typically it is 7 to 15.. not terrible actually... just when it gets dirty it's the biggest problem.





hardwire the switch.. drops about 10-20miliohms. 





solder wick through the spring.

This is by far the biggest improvement.. typically that will measure on the order of 100-120 miliohms.. in-fact.. the 160+miliohm resistance will drop to 80 (half) by ONLY soldering the ends of the spring.. and still using the spring vs the solderwick. 

this solution shown here drops the resistance of the spring to about 3-4miliohm and the whole ckt from the pos. terminal on the PR adapter in this case to about 12 miliohm. 

I made a small change since this picture was taken.. i no longer bother to attach the wire to the bottom.. it comes out a hole on the side at the bottom and is attached to a wire that goes directly to the top contact on the switch. 

Unfortunately i don't have any pictures yet of the battery spring.. but the wire goes through a hole drilled straight through the plastic to the bottom.. a notch is cut in the inner circle and the last 1/2 inch of wire is stripped and the end soldered to the edge of the top of the spring (so that it doesn't interfere with the spring's ability to be pressed all the way down). 

The end result.. the switch i started with measured 500mV drop at 3A.. or 167mohm... after i was done with the modification.. it measured 27.3 mohm.

That puts it in league with the KIU socket kit. most of that resistance is where the spring contact touches the bottom of the PR bulb or adapter.. tough to get around that one.. but even the KIU socket i measured 7mohm between both contacts... this pr adapter to bi-pin i measured 3mohm per contact.. on-par with the KIU.. so since there is probably about 1-2mohm of wire, and 12mohm in the wire and contact.. that means 12-2-3 = 7mohm contact on the bottom of the bulb adapter.. that's as good as the best i've gotten a magswitch with progold (just the contact of the switch).. each contact outside the switch is another full 'contact' which will be about another 7-10mohm typically... and not trustworthy.

So.. the final results.. 

167mohm turns to 28.. 1/6th the resistance!

so a couple examples of 'the difference' using the fixed switch or stock:
1160 on 6V bat.. 5.39 to bulb.. 424/275 L > 5.89V 577/375
1111 on 7.2V bat.. 6.6 to bulb.. 649/722 L > 7.09V 834/542
1331 on 10.8V bat.. 10.46 to bulb.. 720/468 L > 10.74V 790/514
1185 on 10.8V bat.. 10.25 to bulb.. 1026/667 L > 10.7V 1194/776

and my favorite comparison.. a lesson in power transmission.. why does the power company use super high voltage to transmit power.. here is why:

1323 on 14.4V bat.. 14.21V to bulb.. 414/269 L > 14.37V 430/280
(that is 15.6 vs 15.9W)
1183 on 4.8V bat.. 4.19V to bulb.. 274/178 L > 4.68V 406/264
(that is 15.1 vs 18.0). 

so.. barely a difference in output with the high voltage low current solution... but in the low voltage solution... there is a 40% drop in output with the stock switch! 

Well there you have it.. look at the bulb options and see if you are in there.. think about it.. it is CURRENT that causes the voltage drop.. so if you have a bulb with low current you'll be less affected.. this means that the 1060 and the 1185 and the 1183 will be most affected.. 

You may have noticed the omission of the 1166.. it's because it's a sucky solution for direct-drive.. that bulb is underdriven a lot from a 10.8V solution.. enough that there is only a 30 L swing in the output... now that is absolutely a fantastic lamp when pushed properly to 12.5V or so.. 900/600L.. My little 1D FM light is outputting 900/600L for 20 minutes on a charge .. and it takes a cent to charge.. probably not even.. so 3 cents/hr compared to the $8 to $100/hr with the M6.

I hope this helps people.. it is not a terribly difficult mod to undertake.. you just need solderwick, some regular wire (extra flexible type is good.. i used 14ga speaker wire.. and some 18ga wire (which is fine.. 18ga is 1 miliohm per two inches!).. you need a drill, some cutters and of course a 5/64th screw. 

Oh.. very helpful tip.. to solder to the cups.. it's pretty tricky usually.. it can be done with a higher watt solder iron or gun.. but by far the easiest is to hold the cup concave side up... in the likes of the holder shown.. and heat the bottom with a micro blowtorch.. puddle some solder into the cup (careful.. you'll likely start some rosin on fire).. and then touch the solder wick into the puddle of solder.. then put down the flame and use a heat-sink to cool the cup.. else it takes like 10-15 seconds for the solder to solidify. 

if you only solder across the spring and do no other mod.. well .. put some contact cleaner on the slide while it's apart.. you will drop the resistance to about 60mohm.. and that will have this level of result: 

1111 on 7.2V.. 6.6V to bulb 649/422 L > 6.98V 790/514.. comparing to: 7.09V 834/542 if you 'go all the way' 

So.. just fixing the spring will gain you 141L and shorting out all the contacts also will get you 185L gain.. however..that means a 22% vs a 29% gain, so balance how much it's worth in deciding what to fix.

order of importance:

spring spring spring.. over half the resistance
sliding contact... good initial resistance.. TERRIBLE long-term.
outer switch contacts. 

There is a weird thing about how the magswitch is designed.. it is specifically designed to be cheap to assemble and reliable (i'm talking about the electrical switch not the whole assembly).. but at a serious penalty to the electrical resistance.. here is why... 

as anybody that knows ohms law knows.. series resistances add up... 

ANY and EVERY time.. you have a 'contact' you are going to have SOME resistance.. and typically even the very best contacts are between 5 and 10 miliohms.. The problem with the design of the switch is this.. 

Rather than having a hard-wired single SPST switch which could be 5 or 8 miliohms... There are FOUR series switches in a mag switch.. 

(1) contact from + spring pad to switch lower contact
(2) switch lower contact to connecting donut
(3) connecting donut to upper contact
(4) upper contact to PR holder spring contact. 

2 and 3 are exceptionally low resistance.. 4mohm if you treat them.. more like 6 if you don't.. but 1 and 4 are iffy.. 10 to 15mohm is not unlikely.. 
that means.. rather than 5 or 8 mohm.. the mag switch stock is more likely 30mohm to 40 mohm.. easy enough to fix with hard-wiring the troublesome contacts and get it down to 10 or so. 

Hope people can follow and it helps! 

-awr


----------



## IsaacHayes (Nov 29, 2005)

Hehehe good job. I've thought of similar idea, but I don't have incandecents (which your mod would make most sense). All my mags are luxeon, with a wire soldered directly from the switch to the led/driver.

Only points I could improve from what you showed was the battery spring + to switch +, and the switch with that pro-gold.

The C mag has a much different switch too, the D the contact points are much smaller. I would think the C could handle more current and possibly have less resistance? Any thoughts on that?


----------



## andrewwynn (Nov 29, 2005)

I have heard the C switch is better constructed.. haven't taken one apart yet.

I don't have my RT4 switch modified.. it surely drops some power but the regulator is downstream so it only hurts runtime, not output. The battery spring to switch is hard wired... and the switch donut is treated with PG100 of course.. measured a drop from 12 to 8mohm.

-awr


----------



## redbird (Feb 5, 2006)

I have studied the PRSwitchFix on your web site and read and reread this tread over and over to try to get a better idea on how to do this. On your site you dont show the spring cups drilled out. 

Which method is the best to use? What size hole and where does the wire go next?

I ordered a few switches to experiment with so your input would be appreciated.


----------



## andrewwynn (Feb 5, 2006)

the spring cups aren't drilled, just soldered to..






This picture shows how i attached the positive wire to the bottom of the spring. The wire on the right is soldered to the wire near the bottom of the spring. The ground wire is not as important.. by far the most resistance is in the spring and connections.. about 80+mohms.. 

I solder the solder wick inside the cups to the spring top and bottom, and then soldered another wire to the bottom of the spring through the hole that comes out the bottom (black n white wire in the picture) .. that wires goes around to the top of the switch and is hard-wired to the top contact of the switch (it's actually first attached to the switch for easy of assembly)

only soldering the spring and nothing else will HALVE the resistance from like 160 to 80 mohm. additionally fixing the ground will get you near 50 mohm.. going overboard and hard wiring the ground and the positive will get you near 30-40 mohm. 

-awr


----------



## redbird (Feb 6, 2006)

Ok. That is clearer now. I see the hole you drilled on the pics on your web site but it was not clear to me from the notes and pics on your site.

This will help!


----------



## 45/70 (Feb 19, 2006)

Hey, awr,

Is there any way to incorporate your soft start idea into this switch mod? I Have a ROP with the modded switch. It would be really cool if the soft start could just be added into the wiring, retaining the PR base etc. Obviously, I'm not an EE. Soldering, yes. Electronic circuit design, no. 

I have asked elsewhere if a ROP would actually benifit from your Hotdriver. Nobody really said. I'm sure it would but, it seems to me that the best part would be the soft start. It would extend the already, OK, bulb life. The rest of your hotdriver would seem to be overkill on a ROP. Thoughts?

Dave


----------



## 3rd_shift (Feb 19, 2006)

Great post AWR! :goodjob: 
I might also give that one a whirl.
Looks good, especially for hotwire mods at this stage.


----------



## andrewwynn (Feb 20, 2006)

I designed a soft-start circuit that wquiles bench-tested for me.. http://softstart.rouse.com 

It could be made small enough to easily be incorporated into the PR fix.. the combo for many light options (like 1185) would be far less expensive than going the KIU socket and hotdriver solution. 

example of improvement: 

[email protected] host: 471L before, 535 after.
[email protected] host: 662L before 777 after.
[email protected] host: 175L before 258 after. (holy cow! 47% brighter!) just from some wires and solder, no other change!

I want to work out a ludicrously simple regulator that people can build for $5 so they don't have to spend $35 on my hotdriver... the design is already made, i don't have time to build a prototype though. 

-awr


----------



## benighted (Feb 14, 2007)

I know this is an old thread but... I opened up my 6-C ROP to find that the switch style is different now. It looks like [email protected] did away with the double-capped spring and soldered a new style spring directly to the contact. 

Has anyone else noticed this?


----------



## andrewwynn (Feb 21, 2007)

interesting for sure.. the spring is the most of the resistance though.. when the caps are removed from the equation on a D size mag.. the resistance will go from about 80 miliohms vs 180mohm. 

-awr


----------



## Northern Lights (Feb 21, 2007)

It takes some manipulation but I have been soldering the braid inside the spring to the bottom of socket and taking the braid through the spring and soldering it to the postitive contact so that there is no friction contacts whatsoever. I have burned my fingers a few times doing it. I notch the bottom of the slug or put a small hole into it and solder the ground to it. I notch the bottom of the cam wheel channel to accomodate the ground wire. The rest is pretty much the same. On the Mag Charger the pedistal is all metal so grounding is easier but the process is the same for the slug.


----------



## Northern Lights (Mar 11, 2007)

Well, I just had a failure of the ground wire from the slug and I now have a new method of attaching the ground. I do not like making a small loop to be put under the cam screw, too difficult to make, too fragile.
I had been drilling a small hole below the cam screw next to the rim. I also extend the notch of the pedestal down to the switch to accomodate the ground wire. The mag charger slugs I have done are not steel but are an alloy and will take solder. The PR slug is not steel and does not solder well.
On this PR slug that lost the ground wire I put a small soft alloy screw into the hole and made a rivet out of it, pounded it tight and soldered to it. Then I realized that I can drill the hole partially through and braze a spot of brass to it and solder to the brass. Next one I mod or repair will go this route!
Edit:
OH NO! Don't do this, it is a brass alloy after all and plated. But I removed the plating by torching it then polished the now unplated brass PR slug and put a small hold in the base, this time it soldered well. The plating must have had an adverse effect to taking solder even when penetrated by drilling down to the base metal but adjacent to the solder joint.


----------



## LuxLuthor (May 17, 2007)

I think I have read this thread at least a dozen times, and learn something new every time.

In many ways, I miss the educational posts from AWR.


----------



## vhyper007 (May 17, 2007)

hello,
lemme see if i get this straight. simply changing the switch in a mag in the way you described ups the output by diminishing the resistance???

Since I can't solder, this is purely moot since I can't perform this mod but am I on target?

If so, why doesn't someone offer the service where they (for $$) will make this mod and sell it to dufuses who can then drop it into their mags which are now reinvigorated mags. 

Call them ViMagras coz they get the output way up for just a little pill of solder.

Seriously,
vhyper007


----------



## mudman cj (May 17, 2007)

You got it - lower resistance means more voltage at the bulb for brighter and whiter light. This is more effective when running bulbs that draw higher current, and I wouldn't bother for a stock Mag bulb. 

If you ask nicely in the custom/modified forum, I'll bet someone would be willing to mod your switch for you and send it back free of charge or maybe if you cover shipping.


----------



## vhyper007 (May 18, 2007)

thanks very much, mudman. Actually I have several I would like to do so if I asked REALLY NICELY, what do you think?

Regards,
vhyper


----------



## eyeeatingfish (Aug 5, 2007)

I dont really understand where all the wires are going from and too. I understand the wire that went inside the one spring though. About that though, why is there so much wire (why not shorter?) and why did it have to be counterclockwise?

As for the rest of the wires, i guess ill have to take that piece of my mag out so i can get a better understanding of the system than jsut pictures can provide.


----------



## LuxLuthor (Aug 5, 2007)

eyeeatingfish said:


> I dont really understand where all the wires are going from and too. I understand the wire that went inside the one spring though. About that though, why is there so much wire (why not shorter?) and why did it have to be counterclockwise?
> 
> As for the rest of the wires, i guess ill have to take that piece of my mag out so i can get a better understanding of the system than jsut pictures can provide.



Check additional pictures here.


----------



## eyeeatingfish (Aug 5, 2007)

I saw the pictures, i think i will just need to see the actual piece in 3D myself to unaderstand it better. 
Why is the wire in the spring coiled, and why does it have to go counter clockwise?


----------



## fivemega (Aug 5, 2007)

eyeeatingfish said:


> Why is the wire in the spring coiled?


*To reduce resistant of spring while it can compressed with spring.*



eyeeatingfish said:


> and why does it have to go counter clockwise?


*Spring is clockwise and coiled wire must be counter clockwise to stay inside spring without interference.*


----------



## jimjones3630 (Aug 5, 2007)

Someone, think Lasercrazy told me using 10 ga unsoldered wire just wrapped around both ends touching the tailcap when spring snapped in and touching the bat. neg when tail cap screwed in. works as well as soldered.

I've tried it,unsolder, on several and works.

Jim


----------



## Northern Lights (Aug 5, 2007)

I use a piece of braid, snapped in both ends


----------



## Raoul_Duke (Aug 6, 2007)

jimjones3630 said:


> Someone, think Lasercrazy told me using 10 ga unsoldered wire just wrapped around both ends touching the tailcap when spring snapped in and touching the bat. neg when tail cap screwed in. works as well as soldered.
> 
> I've tried it,unsolder, on several and works.
> 
> Jim



Thats what I did in a C tailcap

At the base of the spring, I wrapped wire around in a loop, slid it round to near where the end of the spring finnishes. This is a pinch point and holds the wire firmly in place.
Put the spring in the tailcap, and it is held fast.

I needed to make up a little space in my mag mod as the cells I was using came up a little short, so I used the "crown" or bit that you see at the top of the switch in the first picture in this thread, that screws on and holds the lamp into the holder, ( I used a kiu so I didn't need this bit) and pushed it on the top of the battery touching end of the spring. I then looped the other end of the wire, that I'd attached to the base of the spring around the top, and the fact that it snapped on the top of the spring held it in place very well. 

I'm guessing it works as well as soldering it to the spring, why wouldent it.
The only thing better would be to solder direct to the tailcap, and bottom cell but that wouldnt work for removing the cells easily.


----------



## Northern Lights (Aug 6, 2007)

https://www.candlepowerforums.com/threads/143345

Try this for low tail cap resistance and gives more room in the tail, you set that by making the washer thin or use a rubber tube, like automotive hose.


----------



## jimjones3630 (Aug 6, 2007)

The ways to manage space in mods is amazing.

The rubber hose could be any length even longer than OEM tail spring if have short bat. pak. I have solder 2 OEM springs together in the past but I like the hose idea.

Jim


----------



## bimemrboy318 (Dec 31, 2007)

I've read this a bunch of times and wouldn't it be even better if we did away with the solder wick inside the spring. Instead just solder directly from the upper spring cap to the upper contact. Then you'd avoid transferring power through the solder wick all together... right?


----------



## 3rd_shift (Dec 31, 2007)

Thank you. 
I was just looking for this thread for a 6D hotwire I'm working on. :thumbsup:



bimemrboy318 said:


> I've read this a bunch of times and wouldn't it be even better if we did away with the solder wick inside the spring. Instead just solder directly from the upper spring cap to the upper contact. Then you'd avoid transferring power through the solder wick all together... right?




I was just thinking about that too.
I think I'll give it a shot and see.

It appears that getting rid of as many of the "loose" contacts as possible seems to do the trick.

Half a volt drop at 3 amps is about 1.5 watts of wasted power and heat that might heat something up. oo:

Yeah, I think I'll get to work on the D Maglite switch resistance fixes described here.


----------



## jimjones3630 (Dec 31, 2007)

when wiring bipin adaptors I solder a 18g wire from the bipin pos. to the upper switch contact. I use only non cam reflectors so it's not an issue.


----------



## lasercrazy (Jan 1, 2008)

jimjones3630 said:


> Someone, think Lasercrazy told me using 10 ga unsoldered wire just wrapped around both ends touching the tailcap when spring snapped in and touching the bat. neg when tail cap screwed in. works as well as soldered.
> 
> I've tried it,unsolder, on several and works.
> 
> Jim



Yep that was me.  Speaking of ultra low resistence check this out. Solid 8Gauge ground wire springs. This wire doesn't like to flex too much, so I had to carefully measured it beforehand. Once I bent it into shape I adjusted the height so too much preasure wasn't put on the batts.


----------



## jimjones3630 (Jan 2, 2008)

Nice, that looks tough to get into that wrapped shape, bet it cost less than copper braid and probably as effective. I found a piece of old auto battery copper braided ground cable. It's about 3/4 inch wide and thick use it with Northern Lights tailcap mod. 



lasercrazy said:


> Yep that was me.  Speaking of ultra low resistence check this out. Solid 8Gauge ground wire springs. This wire doesn't like to flex too much, so I had to carefully measured it beforehand. Once I bent it into shape I adjusted the height so too much preasure wasn't put on the batts.


----------



## Germ (Jan 22, 2008)

I tried soldering some Radio Shack solder wick to the spring cups and could never get the solder to wet. What did I do wrong? I even used a Bernomatic torch and couldn't get the solder to wet, the solder would just ball up. The solder was Oatey 95% tin %5 antimony electrical solder.


----------



## Northern Lights (Jan 22, 2008)

I have used common electronic type solders. I usually burnish the spring edge with some sand paper. Take solder off a 30 watt iron.


----------



## LuxLuthor (Jan 22, 2008)

Germ said:


> I tried soldering some Radio Shack solder wick to the spring cups and could never get the solder to wet. What did I do wrong? I even used a Bernomatic torch and couldn't get the solder to wet, the solder would just ball up. The solder was Oatey 95% tin %5 antimony electrical solder.



Yeah as NL said, clean off the old solder, rough up the surface...then I use 60/40 (tin/lead) rosin core after also applying some flux. Check this other recent topic for many others experience.


----------



## Germ (Jan 27, 2008)

I got some lead, 60/40, .050 diameter, rosin core solder from Radio Shack. Using just this (no added flux) and a cheapo soldering iron it was pretty easy to wet the inside of the caps. No lead free ever again. I had some flat braided Radio Shack solder wick.

For my fist try I only soldered the wick to the caps. I cut the wick about 1/2 inch longer than the spring and put little 90 degree bends on the ends. I soldered one end of the wick into the middle of the big cap. Then I put the spring over the wick and into the big cap. Then I soldered the other end of the wick into the middle of the small cap. The wick then collapses inside the spring when the small cap is put back on the spring.

I couldn't really think of a good way to actually solder the spring to the caps. How do you get a soldering iron down in there through the spring?


----------



## Northern Lights (Jan 27, 2008)

Germ said:


> I got some lead, 60/40, .050 diameter, rosin core solder from Radio Shack. Using just this (no added flux) and a cheapo soldering iron it was pretty easy to wet the inside of the caps. No lead free ever again. I had some flat braided Radio Shack solder wick.
> 
> For my fist try I only soldered the wick to the caps. I cut the wick about 1/2 inch longer than the spring and put little 90 degree bends on the ends. I soldered one end of the wick into the middle of the big cap. Then I put the spring over the wick and into the big cap. Then I soldered the other end of the wick into the middle of the small cap. The wick then collapses inside the spring when the small cap is put back on the spring.
> 
> I couldn't really think of a good way to actually solder the spring to the caps. How do you get a soldering iron down in there through the spring?


Good job, I use wick. I also sometimes drill a hole in the cap to bring a wire directly to the pr to bipin sockets I use. 
To solder to the + terminal on C switches the tower dissasembles off, easy access. To D switches I pull the switch assembly out and fish the wire from the spring down into the switch chamber, replace the switch sub assebly and solder to it. I usually have removed the ground bracket to do that.


----------



## LukeA (Jan 27, 2008)

Germ said:


> I couldn't really think of a good way to actually solder the spring to the caps. How do you get a soldering iron down in there through the spring?



You can't solder to aluminum anyway.


----------



## Northern Lights (Jan 27, 2008)

LukeA said:


> You can't solder to aluminum anyway.


" The wick then collapses inside the spring when the small cap is put back on the spring."

This is the switch thread, I think he is refering to the caps on the socket spring. Those are non-aluminum and take solder quite well.
I use 1.5mm soldering wick works very well.
post #1


----------



## Germ (Jan 27, 2008)

Northern Lights said:


> Good job, I use wick. I also sometimes drill a hole in the cap to bring a wire directly to the pr to bipin sockets I use.


 
Thanks Northern Lights. So does everyone just solder the wick to the cups? I was under the impression that everyone soldered the spring to the cups too, I just couldn't figure out how. I've searched for detailed instructions on doing the switch spring mod, but never found any. If anyone solders the spring too, please tell how it is done.

Now I wish I had a decent mult-tester to check if I actually lowered the resistance.

Where do you get the rope type solder wick? All I could find was the flat braided type at Radio Shack.

LukeA, thanks, I didn't know you couldn't solder aluminum. I think everyone naturally thinks "tailcap" whenever you say anything about modding a Mag spring.


----------



## Northern Lights (Jan 27, 2008)

No need to solder the spring to the cups. The path of the circuit is cups through the braid not the sping. If you remove the friction contacts and solder from the switch to the + terminal of a pr to bipin socket the better. If you are using a potted bulb or just wish to drop in a bipin to pr socket then soldering the cups to the braid is the minimum you need. Springs are not good conductors. What you did is adequate for most builds, if you like to squeak ever last lumen out of it you can go further but this takes care of the bulk of the resistance.
Here is a good post of the conductivity:
Electrical conductivity of metals


----------



## fivemega (Mar 28, 2008)

> Please give me a price for a complete setup for this 2D stock mag using your 6AA battery setup. I would like everything needed, including info on fixing the switch.
> 
> Thanks,



*Please see post #1*


----------



## vestureofblood (Aug 28, 2008)

I realize this is kindof an old thread, but its contents were new to me, and here is what I have found.

I used flat braded copper wire (the radio shack kind) and did the spring mod only. And now my M*g74 doesnt come on. Excellent
Here is why.... I am running it on a 2x 32500 li-ion pack from KD. This light has always been dependable, and would turn on almost without fail on the first click. By now several of us have tried useing philps 5761 and had the experience of nothing happening. But this from my 1274? My theory is that this mod lowerd the resistance enough to have a real world effect on my lights. By lowering the resistance the 1274 now trips the PCB circut on my KD cells. If I give it several clicks, or warm up the bulb with my AW C cells first it still works. I also did this mod to my M*g61 and the result seems to be whiter light? At least thats what it looked like to me.

Just wanted to say thanks again for the helpful info.
If anyone is interested here is a fix for the KD D cell 2 pack problem.


----------



## Northern Lights (Aug 28, 2008)

Yes, you are tripping the D pcbs. They are not performing as rated. I am in the process of fixing a 5761 lion D MagCharger. I removed the protection and purchased PCBs from Batteryspace.com and rebuilt the protection. I recieved them in the mail today along with the smart charger that will be hooked to the MC cradle. By lowering resistance you raise Vbulb and get more torch lumens. The NTC is supposed to raise the resistance then back off and give back the Voltage but the new NTCs from Ametherm in the SL12 1R010 have not been reaching a steady state with a low resistance as they were originally rated.

The NTC will raise initial resistance and get by the OEM PCB, that is not trip it, but recently those NTCs have had a steady state resistance higher than they did when I first discovered them and I found that they are dropping the Vbulb to a much lower voltage than anticipated. In and emolie powered light the batteries delivered 7.5 Vbulb but the NTC was dropping in steady state the Vbulb to 6.9 Volts! This barely overdrives the 5761, bright but still can get much more lumens out of it if you can get the voltage to 7.3 Vbulb. I have not had much luck in keeping the bulbs from flashing at a higher voltage. I think 7.1 is very safe after soft start.

I believe for the emolie light I have a problem with I will run a resistor to bring the initial voltage to 7.3 Vbulb from 7.5 and use an AW soft start driver to get it up and running. I have about given up on the new NTCs. 

By replacing the PCB I can keep the Vbulb up at 7.0 to 7.1 and get 80 or so lumens more out of the bulb than with the new NTCs that I have on hand.

I am experimenting with a handful of new part numbers in NTCs, Ametherm did assist me somewhat and suggested a few substitutes but so far I cannot get the Vbulb that I first stumbled on.

I am quite disappointed in the false rating of the protected D cells. They are tripping on 4-5 amps for the ones I have.

Because NTCs change resistance with temperature by putting them in parallel often you get higher resistance and not lower as would be expected by ohms law. You must experiment. Missionaryman did get them to work in a parallel situation also.

YouR success has inspired me to give it another shot and work up some unlikely mixtures of the NTCs I have on hand.

Nice job on the set up.

I like to fuse my NTC set ups too:


----------



## 2xTrinity (Aug 29, 2008)

I recently bypassed the switch on my 2C Mag 5761 with a mosfet, admittedly with no soft-start. 

Before: stock switch. Kiu socket. Resistance-modded tailcap
After: MOSFET handle the current, stock switch drives gate. All else equal.

The mag was as white and bright at <3.9V/cell (open-circuit) as it was before on 4.2V/cell, and required double-clicking, which was never the case before, even with fully charged AW cells. Not surprisingly, it instaflashed at 4.0V/cell.

Based on that, I estimate I was losing about 0.5V at least to the stock switch, which given the 5A draw of the 5761 means the stock C-switch was contributing roughly 100mOhm.

I was quite surprised to see how mcuh difference resistance really made in this case. I was hoping that I would still have enough sag from the batteries themselves to get away with driving the 5761 without building a soft-starter.


----------



## vestureofblood (Aug 29, 2008)

So if I am reading this info correctly, the next time I put fully charged AW cells in my M*g61, with this new resistance fix I can expect a?

My Mag74 not coming on sounded like a good thing, but flashed bulbs are bad.

Thanks Northerlights for posting the new NTC info... let me know if you find some good ones.

Also NL, if you would be so kind as to give a link or a description of the new pcb you orderd, I think that may help me as well. With the new circut will I have you use a smart charger to keep the batteries from overcharging or will the new pcb quit at 4.2v?


----------



## Northern Lights (Aug 29, 2008)

vestureofblood said:


> So if I am reading this info correctly, the next time I put fully charged AW cells in my M*g61, with this new resistance fix I can expect a?
> 
> My Mag74 not coming on sounded like a good thing, but flashed bulbs are bad.
> 
> ...


 
No, the AW cells sag. No poof but it might shut down the protection unless you have a soft start provision, NTC or driver.

Notice the sag:
Discharge data for Phillips 5761 on AW's new C Li-ion cells 

A 2 C-cell light with the AW spacer or an O-ring giving space on the tail cap threads with my snubber
2C Mag Tail Cap mod for AW's "C" cells 
and AW cells is a very good handy light, at one point it was the brightest for the smallest. Yes, you do not get all the potential from the 5761 but until we started using A123 and emolie cells it was top dog. Enjoy it.

I am posting tonight on the new PCB mod I did, it is from batteryspace.com. I will PM you, I have a spare.
http://www.batteryspace.com/index.asp?PageAction=VIEWCATS&Category=711

http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=2774


----------



## vestureofblood (Aug 29, 2008)

UPDATE: So after draining a bit of the overvoltage from my AW cells (down to about 4.09) I slipped the cells ito M*g61 and.... :mecry: there goes a 5761. I am realy not sure what to even do now. I am not liking the idea of having to undercharge the cells each time I use them but removing my new resistance fix sounds like a bummer too. Suggestions any one?

NL thanks. My PM board awaits your message.


----------



## Northern Lights (Aug 29, 2008)

vestureofblood said:


> UPDATE: So after draining a bit of the overvoltage from my AW cells (down to about 4.09) I slipped the cells ito M*g61 and.... :mecry: there goes a 5761. I am realy not sure what to even do now. I am not liking the idea of having to undercharge the cells each time I use them but removing my new resistance fix sounds like a bummer too. Suggestions any one?
> 
> NL thanks. My PM board awaits your message.


 
You need to soft start this mod. Spend the money, its a hobby after all, and get the AW driver and you will have a favorite light!

The only reason I fooled around with AWR, notice the R, drivers and NTCs was to have a plain off and on light. Those lights were used in law enforcement and in real life or death tatics you want the light off and not make a mistake and just dim it of flash it, just on and off, think about it and it is obvious why, otherwise I would put the AW driver in all my incadescents. High, Medium, low and strobe. AW is the best and he is a great friend too.

Using the AW driver/switch combo does away with all the needs this thread addresses. Go for it, you will not regret it.


----------



## m1ruf (Dec 20, 2008)

Sorry to bring this old thread up again but I have a question: :shrug:

is there a similar switch resistance fix you can do on a C-mag switch?

The switch in my 2C mag only has one spring cup (towards the bulb end), is this normal?

Does the C switch have as much internal resitance as the D switch, or less?

thanks for any answers!


----------



## Northern Lights (Dec 20, 2008)

m1ruf said:


> Sorry to bring this old thread up again but I have a question: :shrug:
> 
> is there a similar switch resistance fix you can do on a C-mag switch?
> 
> ...


You can do it pretty much the same way and yes, by the design I would say the resistanc is similar because it comes from the friction fit parts and those are the same.
Usually I drill a small hole in the bottom of the slug becow the cam. Open the plastic slot up to the bottom to accomodate some braid in that position and run the braid back around to the ground screw and solder to the plate. If I am using a Pr to bipin socket, I no longer use the factory cam action as it is useless when compared to premium reflectors, I solder the ground to the ground of the Pr to bi pin socket and solder the positive to the positive terminal coming out of the switch. You must be sure to insulate the appropriate wires.


----------



## vestureofblood (Dec 21, 2008)

m1ruf said:


> Sorry to bring this old thread up again but I have a question: :shrug:
> 
> is there a similar switch resistance fix you can do on a C-mag switch?
> 
> ...


 

Hello m1ruf,

A C mag is what I did this mod to. Mine had only one cup at the end of the spring if I remember right. I took the cup and roughed up the inside and cleaned it with rubbing alcohol, then put a bit of soldering paste in there and heated it with a propane torch and put the desoldering braid in (after tinning the wire and cup),then just soldered the other end to the switch contact where the spring was touching at the other end. I also treated all the other meal to metal contacts with progold. By doing this I got a huge jump in voltage off my 2x AW C cells. Before the mod I could put fully charged 4.2v cells in and had only one instance where the bulb flashed. After the mod 3.9v was about as hot as I could go without a . I have since overcome this as well using a fix similar to the one NortherLights shows with an NTC to soft start the bulb.


----------



## m1ruf (Dec 21, 2008)

thank you for all the answers!:twothumbs

I plan on building a ROP with the following parts:

- new 2c black mag
- download mag c-tower 
- download mac c-ring 
- 2x aw lithium c-cells
- fivemega 8.38mm hybrid mop reflector
- pelican ROP high bulbs

I've ordered two litemania chargers for the aw cells wich automatically shut off completly at 4.2 Volt. 
I already have progold and deoxid. 
I've also got some thermal grease (compound, non-adhesive) for use between the c-tower and the inner walls of the mag bodytube as well as in between the inner walls of the mag head (bezel) and the outside of the reflector. On both paces there is almost no gab existent without the thermal grease (a fraction of a millimeter) as the parts (reflector and c-tower) have been designed to dissipate as much heat as possible to the flashlight body (away from the plastic parts of the stock switch assembly). With the thermal grease inbetween heat transfear should be quite good, I hope.

I already orderd all the parts.

If I do any of the resistance fixes you mentioned will there be a much greater risk of insta flashing the ROP high bulb?
The light should run as reliably as possible (also for longer periods of time) as I plan on using this as a high power duty light (leo). Primary duty light is a SF 6P with Solarforce Q5 single mode Cree dropin, but sometimes I just need even more light (in rural area, city ambient lighting etc).

I think I'll have to balance the lumen gain I'll get from any resistance fixes (switch, tailcap spring) with the reliability of the light...
I also know a ROP is an experimental light and cannot be as reliable as most production lights but this is just a secondary light so I think I should be fine!

Any thoughts/comments on my project are most welcome!:laughing:

Cheers,

m1ruf


----------



## cy (Dec 21, 2008)

Just to clarify names... OP is by AWR (andrewwynn) who ripped off CPF'ers to the tune of $15k+, most still have not gotten their $$$ back. http://www.cpfmarketplace.com/mp/showthread.php?t=163465

AW is a super reputable dealer located overseas, who is responsible for some of the finest batteries/products anywhere.


----------



## EvilPaul2112 (Dec 21, 2008)

m1ruf said:


> thank you for all the answers!:twothumbs
> 
> I plan on building a ROP with the following parts:
> 
> ...


 

Hello m1ruf,

Im a LEO in Milwaukee and use 2C ROP HOLA lights for my main high power lights. The parts list you have is almost exactly as I have. I LOVE downloads C-Tower as it helps keep my light running cool even at long runtimes. I also prefer using potted lamps as I feel they are more rugged and remain centered during rough use. Dont forget to pick-up a good glass lens. I use UCL and have not had any problems. 

As far as the resistance fixes are concerned, I have performed all of them including running a new ground wire. I have NEVER instaflashed a ROP lamp. I run AW "C" cells and charge them with a either a modified WF-139 and or higher quality single LI-ion charger. My ROPs are VERY reliable and have NEVER suffered a failure. Always be sure to clean the lamp with rubbing alcohol after handling. I actually clean mine every time I remove the bezel or about once a month. 

Once you have modified a few switches, you will become more confident in your work. All together I have built about 15 ROPs and the vast majority of them going to other Cops. 

I carry a 2C ROP HOLA on my duty belt. In my duty bag I have another 2C ROP and a 3C [email protected] for back-ups. I use ONLY AW"C" cell Li-ion batteries. All of my lights are equipped with a modamag magclickie tail-switch. This switch is made for AW's "C" cells and does not require an extension to accomodate the extra lengeth. (I persoanlly prefer tail-switches on all of my duty lights). At the beginning of the shift I turn the stock mag switch on and activate the light via the tail-switch. 

Sometimes I will carry the 3C [email protected] for duty but prefer the shorter length of the 2C. The [email protected] throws quite a bit more light than the ROP with almost an hour of runtime. A 3C [email protected] may interest you after you build a ROP or two. 

Good Luck,
PAUL
Milwaukee, WI


----------



## vestureofblood (Dec 21, 2008)

+1 for what EvilPaul said. I too have the FM new gen reflector with the C tower heat sink, and the AW cells. However even with the 5761 bulb which I believe is a bit hotter than an ROP, I only use the thermal grease between the tower sink and the body. Its your light and you do what makes you happy, but it seems to me that the thermal grease anywhere else will be unneeded and will just be a mess, it seems it would also increase the chance of getting it on a nice reflector (cleaning can damage the finish) or the bulb. I don't know how familiar you are with hotwire so, I will again reaffirm what EP said about cleaning the bulb with alcohol and a cue tip or toilet paper. If you get oil from your fingers or thermal grease on it the oil will heat up so hot it can explode the bulb, ( i had a wa1185 blow up and gash the reflector, its somthing i'll not let happen twice). Any way good luck.


----------



## Northern Lights (Dec 21, 2008)

I never used thermal grease in any of the 5761's I have built and they see some run time as I use them in the hot desert, LEO also. 
The latest two 5761 I have gotten right up to the flash point finally. They run as hot as they will ever get.

The ROPs I never flashed, it is a stout bulb. If you look here:
http://i61.photobucket.com/albums/h75/pike444/bulbs/3854-HROP.jpg 
From
They take up to 8.5 volts, we are under driving them as discused in the thread:
Destructive Incan Bulb Tests - Updated 6/22/08 (Info Added) 

The 5761 is also pretty stout and runs a long life aslong as you stay under the flash point.


----------



## vestureofblood (Dec 21, 2008)

Edit: nvm


----------



## m1ruf (Dec 23, 2008)

Hey all, thanks for all the useuful info an advice!:goodjob:

Great to see some other people in the same profession using a similar setup.
In my last post i forgot to mention that I of course ordered some Borofloat lenses, too!
Thanks for reminding me not to touch the hotwire bulbs and to clean them with isopropyl etc. I always take care with my other lights and never touch the bulb or inside of the reflector, batterie contacts etc.
But with these high power incan bulbs you've got to be extra careful!

Good that you mentioned maybe not to use the thermal grease between the reflector and the inner bezel walls, I'll follow this advice for now, as I already made a mess when putting the thermal greased C-tower-switch back into the light ( I used too much grease and the excess grease smeared all over the inner body tube; took me half an hour to clean it out again; I can only imagine what it would do to the inside of the reflector, or even the bulb!)

Anyway this will be my first hotwire build. So far I've done the c-tower installation + the switch resistance mod. Now I'm anxioussly waiting for the rest of the parts to arrive (lens, bulbs, batteries, chargers) so I can fire my first ROP up!:devil:


----------



## Jarski (Dec 27, 2009)

Sorry for bumping this old thread. I tried to do that spring mod, but I failed to do it. I tried with my 30w soldering iron, but it didn't fit in the cup and I didn't anything to attach them to keep them in place. So, does this mod make noticeable difference with ROP?


----------



## vestureofblood (Dec 28, 2009)

Jarski said:


> Sorry for bumping this old thread. I tried to do that spring mod, but I failed to do it. I tried with my 30w soldering iron, but it didn't fit in the cup and I didn't anything to attach them to keep them in place. So, does this mod make noticeable difference with ROP?


 
Hi Jarski,

When I did this mod I added the piece of braided copper wire to the center of the spring, but to do it rather than the soldering iron I used a pencil torch. I roughed up the inside of the cap a bit and put a little flux in there and held it with some pliers. Then I cut a small piece of solder and dropped in. I held the cap over the torch until it melted and stuck the braid in and let it cool (touched the bottom to a piece of ice). IMHO this by itself made a noticeable difference for my M*g5761 project. With this and some progold on a 5761 bulb it raised the VF to the point I had to make a soft start to keep from ing the bulb. With an ROP I dont think blowing the bulb will be an issue (if you are using 2x li-ion or 6x nimh) since the flash point is higher for this bulb.

If you don't have a torch, you could probly use a stove burner, I think either a propane or even setting it on an electric would probly do the trick.


----------



## Northern Lights (Dec 28, 2009)

Using de-soldering braid I ran a piece from the bottom to the top of the spring. I roughened the inside of the cap and made sure the cap threads were clean for good contact.

The braid I wrapped around the spring wire and soldered the braid closed. The braid is soldered to its self and captures the spring wire. The braid makes contact to the cap and to the bottom of the battery. The spring holds it in place is all.

You must heat it too hot to solder it to the spring in most cases which changes the spring temper.

Over the years I believe I have showns with the many experiments, mods and posts the 5761 puts out a bigger and beam and more lumens than the ROP and teh ol' '85 at only 7.2V!! Your ROP will benefit with the mod.

I found this modification and a modification to the switch to be very beneficial in providing more power to the bulb.

Have fun and look forward to building more and brighter!
As an after thought, a picture. The bottom connection shows the wrap. It is turned around for the photo. The top is isolated because the circuit has a fuse. The second photo shows an alternative to the spring. link: *2C Mag Tail Cap mod for AW's "C" cells* and link:
*Tail Cap Spring Substitution Solution!*









NL


----------



## fivemega (Dec 29, 2009)

http://homepage.mac.com/rouses/circuits/PhotoAlbum373.html


----------



## Jarski (Dec 29, 2009)

vestureofblood said:


> Hi Jarski,
> 
> When I did this mod I added the piece of braided copper wire to the center of the spring, but to do it rather than the soldering iron I used a pencil torch. I roughed up the inside of the cap a bit and put a little flux in there and held it with some pliers. Then I cut a small piece of solder and dropped in. I held the cap over the torch until it melted and stuck the braid in and let it cool (touched the bottom to a piece of ice). IMHO this by itself made a noticeable difference for my M*g5761 project. With this and some progold on a 5761 bulb it raised the VF to the point I had to make a soft start to keep from ing the bulb. With an ROP I dont think blowing the bulb will be an issue (if you are using 2x li-ion or 6x nimh) since the flash point is higher for this bulb.
> 
> If you don't have a torch, you could probly use a stove burner, I think either a propane or even setting it on an electric would probly do the trick.



I'll try this. Thanks!


----------

