# Guide to a 2C Mag 5761 w/ SoftStart (pics)



## Timaxe (Jan 5, 2008)

I'm not sure how many light building guides there are other than the ROP guides, so I decided to document the building of my own Mag61 light. There are some people asking for help, so this should help them out a bit. Unfortunately, at the time of this writing, AW is out of stock on his C sized Lithium-Ion cells. Hopefully we will see them again in the near future so people can continue to build this hotwire light.

This hotwire mod uses the Phillips 5761 bulb _[Link to LuxLuthor's Destructive Incan Tests]_ and 2 "C" sized Lithium-Ion rechargeable batteries. This combination produces enough light to show up on LuxLuthor's list of incan lights _[currently at number 9]_, which is a good reference to find usable combinations of batteries and bulbs once you have a feel for what parts/mods are necessary to get those particular combinations to work well together.

This was my first "hotwire" modification, and I enjoyed getting the parts together and using this light.

Mag61 Contents (note: first location entry is where I got parts from, I tried to list another if parts are unavaliable):
1x 2C MagLite [B&M Store]
1x Phillips 5761 Bulb [Bulb Connection]
1x Camless MOP Metal Reflector**1,2* [fivemega]

1x 52.1mm Borofloat Lens**** [lighthound, flashlightlens.com]
2x "C" sized Lithium-Ion Cells**** *[AW - sold out, recommend protected cells]
1x AW V2 Mag C Incan Driver****** [AW]
**1 *The opening for a 5761 bulb needs to be at least 10.5mm or 0.41in. I used a 27/64 sized bit to get a 0.422in hole because when I ordered only 8.38mm opening reflectors were available.
**2 *A camless reflector is used for the AW driver. This is because the height is fixed. If you use a NTC and keep the Mag post that allows height change, you could use a cammed version. But if your NTC build uses a KIU socket to replace the top half of the mag switch you'll need a camless reflector.
*** *A UCL lens allows better light transmission, but might shatter due to thermal expansion along different parts of the lens. I went with Borofloat, but there is a possibility that UCL lenses will work. Also note that technically ours lenses are called windows because by being flat, by definition they don't bend light like a curved lens does.
**** *Please only use lithium-ion cells if you understand how unstable these types of cells are and accept the risks - and then get a well protected cell whenever possible such as those offered by AW. And please invest in a multimeter and learn to measure voltages to ensure that your charger charges correctly/safely. Also note that most protected cells will trip and require multiple "clicks" on the 5761 bulb because it draws more than 5.5A when the filament is cold. See note below on driver/NTC use.
***** *This part handles soft-starting to allow AW's 5.5A protected cells to work with the bulb (the 'cold bulb' current trips the 5.5A protection circuit, but when the bulb is hot there is enough resistance that the protection circuit is not tripped). A NTC thermistor can be used at much less expense (as done by user "Northern Lights"), but you will need to modify the stock mag switch to accept Bi-Pin bulbs. Using AW's driver replaces the entire switch assembly and makes for less headache. If you decide to use a NTC thermistor, you will need to research that topic as I did not go that route. This thread seems to have a couple of links that lead to NTC thermistor posts: https://www.candlepowerforums.com/threads/172095

​Build Steps:
Unscrew tailcap from back, remove batteries (if any).
Remove rubber boot that covers the switch button on the light body
With a small hex tool, unscrew the switch retaining screw located inside the hole on the switch. [see white switch, photo 2]
Drop the switch out the body, it slides down the battery tube
Unscrew light head from the body, and then disassemble the light head by unscrewing the window retaining ring to remove the stock reflector. [see photo 1]
Insert new components (metal reflector and borofloat window) and then reassemble the light head.
Install the new switch thought the back of the mag body similar to how you removed the old one. It should have a screw the hold it in place above the black button near the back, so look for it carefully - ensure the new switch is secure.

Install bulb in the bipin holder. Use rubbing alcohol on a cloth to clean oil/finger prints from the bulb.
Install the mag head with new components on the body tube. Do this slowly and make sure the bulb fits in the hole on the reflector - if it doesn't reposition the bulb or enlarge the hole in the reflector.
You will need to cut down the tail spring to use protected lithium ion cells because of their longer length compared to stock cells. [see photo 3, photo 4]
Install new batteries, then put the modified tail cap on.
Use flashlight. :twothumbs

Now for the photos! 

1. stock mag reflector vs fivemega MOP reflector, and stock mag bulb vs phillips 5761 bulb.






2. stock mag switch w/ bulb vs aw v2 switch w/ 5761 bulb





3. size difference between regular C cells and lithium protected C cells





4. modified tailcap spring - it may need to be a bit shorter than what is pictured here. be sure to bend the cut top towards the center of the spring a bit and to sand it down so the tip isn't too sharp.





Goodluck on your builds!


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## bxstylez (Jan 5, 2008)

this should be sticky!

nice tutorial!

.


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## littlejohnle (Jan 5, 2008)

Great job with nice pics.

Any plans for other tutorials?


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## jimjones3630 (Jan 5, 2008)

Nice tutorial and easy to follow.

here is one source for the NTC used with 5761.

http://www.newark.com/72J6730/passives/product.us0?sku=AMETHERM-SL12-1R010&_requestid=243717

Here is a thread about protected cells and use with 5761.

https://www.candlepowerforums.com/threads/177344


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## Northern Lights (Jan 6, 2008)

Here are some variations to add to it. 
Smooth reflectors produce longer throw, Frosting the bulb up just past the filament for 35 minutes with Armour Etch produces a bright smooth beam.
The NTC can be put in the tail cap.
https://www.candlepowerforums.com/threads/170972
https://www.candlepowerforums.com/threads/177344
MY IMAGE SHACK ACCOUNT WAS HACKED AND THE IMAGE IS GONE! I WILL REPLACE IT!




An altrenative solution to the tail cap so the standard cap without a spacer can be used with AW cells and 2C light, NTC works in this too.
https://www.candlepowerforums.com/threads/162767
Using AW cell, Emoli or A123 a charging jack can be added and the batteries safely charged in series. Emoli and A123 use a 3C host and the AW cells do nicely in a 2C with AW spacer for the jack mod.


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## ElectronGuru (Jan 6, 2008)

Another tailcap option:


https://www.candlepowerforums.com/threads/159659


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## ElectronGuru (Jun 14, 2008)

Another tailcap option:

https://www.candlepowerforums.com/threads/160004


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## Timaxe (Apr 3, 2009)

It has been a long time since posting this topic, but for completeness I'm posting photos of the KIU socket mod which I did this week. Unlike the soft-start regulator this thing is instantly on at full brightness.










This is a nice change from the soft-start turn-on time, but does increase the chances of burning out the bulb filament upon starting. If your battery has current limiting safey circuitry built-in, there is also a chance that you'll need to perform multiple clicks to get started with this.

If it works for you, this is a great solution. Otherwise you may need to look into various soft-start ideas such as the power NTC thermistor (gets very hot, may not be good around heat sensitive parts such as plastics or batteries)


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## Per Arne (Apr 14, 2009)

How do you get the switch module out of the maglite barrel (pictures please) :thinking:

Thanks,
PA


ps: I have tried, but how long do I have to screw the mentioned switch and how much force do I have to use to push the module out? I am little bit worried to damaged the module...


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## 737mech (Apr 19, 2009)

Timaxe said:


> .


 
Why is this tailspring wrapped with copper wire like that? If you shorten the spring for the AW c cells is this necessary?


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## Outdoors Fanatic (Apr 20, 2009)

737mech said:


> Why is this tailspring wrapped with copper wire like that? If you shorten the spring for the AW c cells is this necessary?


That looks hella ghetto.


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## supasizefries (Apr 20, 2009)

I believe it's to lower the resistance of the tail cap.


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## 737mech (Apr 28, 2009)

Just built this light and it works great and is very very bright. I came up with one problem though. I have the Fivemega reflector and put all the shims in the switch but it still has a huge doughnut. The bulb needs to be adjusted higher but there is no more adjustment. Any tips? Also will this work with 2 18650's?

This light works with my AW C cells but for some reason not my 2 Tenergy 18650 cells????


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## S.E.G (Apr 29, 2009)

I've been running a couple of Custom HAIII 2C Mag 5761 with an AW soft start since 2007 and its a great combination of light weight and awesome throw, but I've have to list one of them in the CPF market place to fund the purchase of a Surefire M4.


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## Juggernaut (Sep 13, 2009)

737mech said:


> This light works with my AW C cells but for some reason not my 2 Tenergy 18650 cells????


 
That’s because there is no way a 18650 cell “except fro IMRs” can handle 5.5 amps.


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