# Modified Coleman Retro 8D Lantern (1200 Lumens Cree X-ML)



## DaMeatMan (Dec 7, 2012)

Hey Folks,

I thought i would share my most recent mod of an 8D Coleman Retro Lantern. This lantern was rated at 395 Lumens using it's stock CFL bulb. Well although this lantern served me well when i bought it several years ago, it just wasn't cutting it for me anymore. Since it was just collecting dust in my closet for the past couple years, i decided to update it with today's latest LED tech. This lantern is actually a great host for modding, i gutted the internals completely and decided on the following for my mod:

- 2 x Cree XM-L U3 1C Bin LED's
- 1 x Lopped off dome head diffuser from a Philips LED bulb that i sacrificed while investigating it's internals
- 1 x BuckBlock driver running at 1.4amps Max
- 1 x 20k ohm potentiometer for very smooth dimming from 0 - 100% brightness

I got to tell you that I am super impressed with this mod, and it is definately the brightest battery powered lantern i have ever seen. It definately beats out anything currently offered by Coleman and the light quality is super smooth and diffuse with no beam artifacts!

Enough talk, now onto some pics!

Here is a pic of what the 8D Coleman Retro CFL lantern looks like in stock form






Here is a pic of the modified lantern (2 x Cree XM-L U3 with 1.4 amp BuckBlock)





Here is a comparison shot of my modified lantern next to my 8D Coleman Twin LED Lantern (modded with 2 x Cree MC-E, everything else stock)





Here we have a control shot, with a 40 watt incandescent Bulb lighting my bedroom from my night table lamp.





Here we have the 8D Coleman Twin LED Lantern on highest setting for comparison. You can see that the incandescent is still significantly brighter.





And finally here we have my modded 8D Coleman Retro lantern on highest setting running at 1.4 amps and putting out aproximately 1200 Lumens (at the emitter). You can clearly see that it lights up the room brighter then the 40 watt incandescent, and the 8D Coleman Twin on high.





Let me know what you folks think, and feel free to ask questions. I'm sorry i got too excited putting this bad boy together that i forgot to take pics of the build along the way. By the way, in case your wondering, the pics were taken with my Samsung Galaxy with settings set to fixed and not auto.


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## zespectre (Dec 7, 2012)

NICE!
I'm guessing that since the housing was retained it still has the same water/damp resistance and so forth?
Any idea on runtimes?


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## DaMeatMan (Dec 7, 2012)

Same housing was retained, and it should have the same water/dampness resistance as stock if not better. The reason i say it may be better is due to the fact that the original circuit board in the device had it's compenents "open to the air". However with my mod the circuitry in the BuckBlock driver is completely sealed and self contained. It's also low voltage compared to the high voltage step up driver required to light the stock CFL, so i would say it's a bit safer and less susceptible to moisture issues.

With regards to run time, i have yet to test it to see what real world figures will give me. But based on the theoretical numbers i would estimate the following:

Based on 8 D Alkaline batteries at the following current drain. Assuming a D cell alkaline offers 10,000mah (based on a quick google search)
Calculations performed using LED Runtime calculator assuming forward voltage of 2.9v x 2 in series for a total forward voltage of 5.8v.

13 hours on high @ 1.4amps
26.6 Hours on Med @ 700 milliamps
53 hours on lower settings @ 350 milliamps (you can go lower with this driver, not sure what the lowest usable setting would be drawing current wise. I would have to measure to test)

One point i forgot to mention was the addition of a white reflector under the lantern cover. This was simply a cut out from a margarine container lid. The result was a nice diffused amount of light reflected back downwards below you when you hang it on a tree or something without harsh glare blinding you.

If any of my numbers are off, please feel free to correct me folks.

Here is a pic of my margarine reflector... lol


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## DaMeatMan (Dec 7, 2012)

I should also add that i still need to create labeling for the face plate control knob. And i also plan to add a 12 volt line input under the fuel cap. This will be super useful in a camping type situation where you may have a car parked nearby, or great for use as a work light around the car. I say 12v input, but really the buckblock will handle anything up to 32v DC input without any issues. To do this properly without causing battery leakage issues with the D cell alkaline batteries, i plan to add a switch that will switch between internal batteries and the external power input so that they are both isolated.


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## Lynx_Arc (Dec 7, 2012)

DaMeatMan said:


> I should also add that i still need to create labeling for the face plate control knob. And i also plan to add a 12 volt line input under the fuel cap. This will be super useful in a camping type situation where you may have a car parked nearby, or great for use as a work light around the car. I say 12v input, but really the buckblock will handle anything up to 32v DC input without any issues. To do this properly without causing battery leakage issues with the D cell alkaline batteries, i plan to add a switch that will switch between internal batteries and the external power input so that they are both isolated.


Just use a standard DC input jack they have a bypass on them when you plug into them you can have it connected normally running batteries and then bypass them when you plug in a DC power plug.


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## lumen aeternum (Dec 8, 2012)

How many Watts was the stock CFL? Was it turning the batteries into 120v AC ?


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## DaMeatMan (Dec 8, 2012)

The stock bulb is labelled as a 15 watt 6500K CFL. The driver was 12V DC to AC, however i never bothered to measure the output voltage on it. The CFL was a non standard 4 prong plug that was not labelled, so i didn't really want to mess with it much.

I can tell you that my mod runs at only 8.4 watt's on high and it's absolutely murdering the output of the stock lantern at 15w. It's a shame i didn't have the foresight to take a comparison shot of it stock, however i can tell you that the light output was dimmer then my 8D Coleman Twin LED lantern pictured above. I would say it was the equivalent of that lantern at 75% - 80% brightness.


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## Altec (Dec 9, 2012)

Who did you purchase the buckblock through? I've been thinking about one for a drop light build, and this build has me sold.


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## DaMeatMan (Dec 9, 2012)

Altec said:


> Who did you purchase the buckblock through? I've been thinking about one for a drop light build, and this build has me sold.



LED Supply has them.
http://www.ledsupply.com/led-drivers.php


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## DaMeatMan (Dec 10, 2012)

Lynx_Arc said:


> Just use a standard DC input jack they have a bypass on them when you plug into them you can have it connected normally running batteries and then bypass them when you plug in a DC power plug.



Thanks for that Lynx! Had no idea this feature was already built into standard DC Jack, found some that will work this way and have them on order now.


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## Lynx_Arc (Dec 10, 2012)

DaMeatMan said:


> Thanks for that Lynx! Had no idea this feature was already built into standard DC Jack, found some that will work this way and have them on order now.


Your Welcome. I have converted a few battery (only) powered devices to use AC power with them via wallwarts. Just remember most DC power jacks/plugs have center pin as positive +, and the cutoff (switching) is done on the ground so you will have to cut the ground power to your batteries and route it through the DC Jack so it can be bypassed when you use the DC input. It sounds like you could even get a 12VDC car cord and/or use external battery power for it also if needed saving your batteries for later.


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## DaMeatMan (Dec 10, 2012)

Lynx_Arc said:


> It sounds like you could even get a 12VDC car cord and/or use external battery power for it also if needed saving your batteries for later.



That was exactly my thought. I always have an emergency power pack/car booster handy with built in AC inverter and DC cigarette lighter socket, one in the home, and one in the car when camping. So a 12v cig lighter jack into this would be an ideal power backup with insanely long run times. Not to mention the power pack could always be recharged quickly and easily in the car.

With the success of this mod, i think the next project will be to convert the 8D Coleman Twin LED lantern to 2 Cree X-ML U3 with a 2100ma buckblock for an aproximate 1500 lumens (at the led). The fact that the LED is mounted up top on this lantern and facing downwards, will give me a better way to manage heat as it can vent through the top mantle, and thus allow me to drive it a bit harder. The ultimate goal when running off of batteries for me is always going to be long run times with reasonable light output, so i would suspect i would run it at med most of the time. However when external power is an option, it is always nice to have the option to pump out more lumens from one single lantern without having to resort to dangerous fuels and combustion in the home.

I'm totally stoked at the fact that with a bit of modding i'm currently running something that will probably take Coleman another year or two to commercialize something with similar light output. And it's also nice to know that my lantern is now on par with most fuel based lanterns in terms of light output and run time!


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## Lynx_Arc (Dec 10, 2012)

I think the problem with most larger lanterns is the alkaline D cell usage. I have a 4D remote fluorescent lantern I was thinking about converting to LED but I couldn't figure out how to bypass the fluorescent circuitry to replace it with a DC based LED driver section. I think it would be cool to have a lantern with a laptop type battery setup with charger running 18650s myself as an 18650 has about twice the power of 3 D cells and under a 2 amp load probably closer to 3-4 time the power such that 3 in series could run a lantern about twice as bright for the same length of time using LEDs. You can put a bunch of 18650s in an 8D lantern when you pull out the battery compartment section.


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## DaMeatMan (Dec 10, 2012)

When it came to modding my lantern i figured i was going to commit to doing it one way or another, so i just yanked that sucker out! I actually broke up part of the circuit board while trying to figure out how to remove it from the lantern. But what i found was that there is tonnes of room inside for my driver and heat sink. The other really cool thing that i found, is that the old driver actually had an aluminum heat sink for one of the components. I removed it and found that it fit perfectly flush with the void from the socket of the old CFL. I now had a flush mounting point for the LED's that looked as if it was manufactured for use this way! I ended up epoxying some heavy metal bolts to the bottom of that aluminum heat sink to give it more mass to absorb heat. I really feel like an idiot now for not taking pics of this part of the build, as it would probably greatly help anyone who has the same style lantern that wanted to attempt this mod. In any event, i know steel bolts is not exactly the ideal heat sink material, however the aluminum block that the LED's are mounted to really did not get that hot when running at 1.4 amps, so the bolts were really just extra mass.

I say if your not entirely attached to your lantern, and your committed to making it better then just go for it! How many mAh hours can you get out of those 18650 cells? I also bought some Soshine 2AA to D cell parallel adapters so i can run the lantern on my Eneloop AA cells which would give me about 4000mAh - 5000mAh. Even in this config i figure i could get about half the run times of the D cell alkaline's with the added advantage of a lighter lantern that can be recharged again and again.


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## Lynx_Arc (Dec 10, 2012)

DaMeatMan said:


> How many mAh hours can you get out of those 18650 cells? I also bought some Soshine 2AA to D cell parallel adapters so i can run the lantern on my Eneloop AA cells which would give me about 4000mAh - 5000mAh. Even in this config i figure i could get about half the run times of the D cell alkaline's with the added advantage of a lighter lantern that can be recharged again and again.


You can get cheap 18650s from laptop battery packs that have 2200mah at 3.7v. Essentially 1 of them is about the same as 3 eneloops in series so 4 would be about 12 eneloops in parallel/series or about 8800mah at 2.1A they should run 4 hours


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