Building a ROP

KevinL

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One of the failings of my Roar of the Pelican (ROP) project is that it has not been well documented. I've decided that it's high time something be done about it!

In a nutshell, the ROP is a hotwire incandescent light capable of delivering 1150 lumens at the bulb before optical losses. Of course, this amount of light tends to be quite pleasing except when you are on the receiving end /ubbthreads/images/graemlins/crackup.gif

Part of the attraction is that it is easy to build, it requires no special bipin holders or extensive modifications to the light. If you can change batteries and bulbs, you can build this light!

You also have a choice of two lamp assembles for high and low output. "Low" produces something in the range of 550 bulb lumens, so its name is only relative!

Runtime on 3600mAH Sanyo high current Sub-Cs is in the region of 50 minutes on high, 2 hours on low. If you use the alternative recipe (detailed below) and CBP1650s, expect 20+ minutes on high and 40+ minutes on low.

You will need :
1. Maglite. See below for sizing
2. Borofloat glass from flashlightlens.com, 52.1mm for Mag D
3. Carley RF1940 METAL reflector, or equivalent from folks such as modamag
4A. Batteries and battery holders depending on your configuration. If you are following mine, get a straight stick of six Sub-C cells built for you and nicely shrinkwrapped, like I did. Stick should produce 7.2 volts nominal voltage and be able to handle at least 5 amps discharge. I recommend GP or Sanyo Sub-C high current cells. My first choice was GP, but the Sanyo has performed extremely well and I can't say I'm disappointed. Highly recommended. You MUST use the 4D Mag for this config. You must also have a charger capable of charging six cells in series (pack charger) such as the Maha C777Plus2 or Triton.

4B. If you want a smaller light or if you do not have the equipment to charge sticks, you can build the ROP into a 2D Mag if you use Elektrolumens' excellent 3AA-to-D holders. You need two holders, and six CBP1650 AA cells from cheapbatterypacks.com (CBP). These AA cells are special NiMH cells that can tolerate up to 10 amps. As a bonus, they can be unloaded from their 3toD holders and charged in normal AA NiMH chargers. DO NOT put the holders in a D-cell NiMH charger. Unload the cells first and charge them individually.

CBP also builds the above Sub-C sticks if you need them.

5. Last but not least, the bulb. The ROP uses a bulb by Pelican, originally intended for their Big D spotlight. You can obtain these bulbs as replacement part number #3854 . Please pay particular attention to the part number as there is an equivalent replacement kit intended for the alkaline-powered Big D, with 8 watt bulbs. This is not what you want. #3854 provides an 11W (low output) and 24W (high output) bulb.

These are the bulbs:
rop1.jpg



Now, on with the build instructions.

If building configuration 4A, you will need to obtain the spring from the Mag 4D, and cut the spring down to size. The idea is to make the spring fit further back in the center of the tailcap.
rop2.jpg


You must remove the anodizing from the tailcap. Here I am shown scratching it off with a screwdriver and 200-grit sandpaper. A more efficient method, if you are comfortable with handling caustics, is to pour lye in. As I don't have lye and would prefer not to work with toxic chemicals, I took the other approach.
rop3.jpg


As shown in the battery pack picture, I have wrapped mine in 5 layers of plain white paper and taped the paper, in order to make it fit the larger diameter of the Mag. You can use PVC or heater hose or other suitable materials.

The spring will then fit and make contact with the silver surface of the tailcap. Make sure the base of your spring touches the silver metal of the tailcap.

If you are building configuration 4B with the six AA cells, simply put them into the holder following instructions on the side, put the holders into the 2D Mag the normal way you would load D cells. No springs or anything needed.


Next, get your bulb:
rop4.jpg


The 24W high output bulb can be distinguished by its pointy tip, as opposed to the rounded lens tip of the 11W low output bulb. I highly recommend NOT touching the bulb with your fingers. If you accidentally touch it, wipe it off with isopropyl alcohol and leave it to dry.


Remove the bezel of the Maglite:
rop5.jpg


Remove the existing plastic lens and substitute the Borofloat glass lens. Remove the existing reflector, and substitute the metal reflector. If you leave the original components in there, be prepared for a very messy plastic meltdown as the plastic cannot take this level of heat.

Close the head back up.

Install the bulb as you would any ordinary Maglite bulb, and screw the head back onto the Maglite. Point away from your face and light it up. If you have done everything right, you should be rewarded with a huge blast of light. Enjoy!!


Edit: Credit must be given as to where credit is due and I have found the original thread with all others who have taken this idea from "I'm thinking of a .." to finally enjoying the finished product. THANKS GUYS!! /ubbthreads/images/graemlins/happy14.gif
 

js

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Aug 2, 2003
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Kevin,

Thanks so much for taking the time and effort to document the ROP! A definite service to the hotwire community.
 

jdriller

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Feb 9, 2003
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New York
I have also followed Kevin with the ROP mod, but I used a different battery configuration.

I used Wilkey's high cap. 4Ah 5 1/2 D cell + one extra 1/2 D.

True, you have to have the cells, but boy is it bright!

Thanks for the easy hot wire mod Kevin. /ubbthreads/images/graemlins/bowdown.gif
 

Phaserburn

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For those interested in the output of this mod but not the work, get yourself a Pelican Big D Nicad version. It will overdrive the above bulb in the same fashion, using 6 D Nicad 5Ah cells. An out of the box 1100+ lumen monster!
 

KevinL

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jdriller: nice cells!! /ubbthreads/images/graemlins/happy14.gif You're most welcome, just sharing what I've discovered. I believe the original idea of using the Pelican bulb was suggested by someone else. I went Sub-Cs for lower weight after hearing the GP's could do 30 amps and Ginseng said he loved those.

But the 1/2 Ds are legendary in their own right!


Phaserburn: yeah, that definitely works - it has to, seeing as to where the bulb came from /ubbthreads/images/graemlins/grin.gif Does it have a charge-in-place system?

D NiCads.. wow.
 

Phaserburn

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KevinL, yes, it has a charge in place base that the whole light snaps into. It can also be wall mounted, etc. Yeah, I thought D Nicads were a curiousity also, BUT... they are lighter weight than nimh (which, for 6 D cells, is worth noting), forgiving of being trickle charged, and totally willing to effortlessly cough up the 4+ amps required when overdriving. With a capacity of 5Ah relating to a good hour's runtime, I just haven't seen the need to go with a nimh pack that is sure to run over $50. If I need to go with long runtime, I guess I'd just slip into the "low" bulb, which as you know, is no slouch. They can also drive the 200 lumen (before calculating the overdrive, which likely puts it into the 325+ lumen range)alkaline version bulb for 4+ hours; not many lights can produce that kind of light with that much runtime. Using nimh would just double the fun...

This setup, BTW, smoked a Mag85 in side by side comparison at Photonfest4 at Milkyspit's house in NJ; output and definitely throw, due to the larger Big D reflector.

I repeat: this light is a CPF sleeper. I can only guess that most have an aversion to the lantern-esque handle/styling of the Big D, preferring the Mag 3D instead. Personally, I also like the nice carry strap it comes with; it's good quality. Considering that the Big D is an out of the box powerhouse while a Mag85 takes a bit of doing, I'm surprised that it's not a more popular choice. Maybe folks don't like yellow!
 
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