What to do, what to do... (4D Maglite

So, I'm thinking about trying my own mod for the first time, and lo and behold, I find an old 4D Maglite while digging around in my closet. I already have a couple of "close work" lights, and I'd really, really like a good thrower. Is this a good base to start a build with? How much light could I reasonably expect to be able to throw with this thing? I'd like to be able to stick with alkalines, but might be convinced to buy some LiIon's if it'll get me a huge number of lumens. Help a noob modder out here!

I posted a thread not long ago that has some suggestions from others in it:
https://www.candlepowerforums.com/threads/268911

I still haven't gotten around to doing anything. It looks like a substantial project and I need to finish a few other things first.

GreatDane said:

So, I'm thinking about trying my own mod for the first time, and lo and behold, I find an old 4D Maglite while digging around in my closet. I already have a couple of "close work" lights, and I'd really, really like a good thrower. Is this a good base to start a build with? How much light could I reasonably expect to be able to throw with this thing? I'd like to be able to stick with alkalines, but might be convinced to buy some LiIon's if it'll get me a huge number of lumens. Help a noob modder out here!

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If you want to run on alkalines (and I assume in full regulation), then you probably shouldn't load the cells with more than 1A draw.

That probably suggests building a Seoul P4 or Cree XP-G Mag mod. With a 4D Mag, you could use a cheap buck driver like a DX26110 or KD1640.

If you want a lot of lumens, you can use an 8xAMC7135 based driver and 4xAccuPower NiMH cells to power a Seoul P7. Four NiMH is a little excessive in terms of Vbatt, and thus driver efficiency. So you'll burn up some extra wattage as waste heat. But it'll definitely work, it's cheap, and it'll have long run time. The build procedure is well-documented in StefanFS's P7 Mag mod guide.

If you really want lumens from a 4D Mag, see this.

Go with 5 IMR 26500's and a Osram 64458, this will produce insane output especially with a Fivemega throwmaster or FM3-X. Great thing about this setup is you can also use a 64440 or 64447 for longer runtimes but still retaining a lot of output.

mrartillery said:

Go with 5 IMR 26500's and a Osram 64458, this will produce insane output especially with a Fivemega throwmaster or FM3-X. Great thing about this setup is you can also use a 64440 or 64447 for longer runtimes but still retaining a lot of output.

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Sorry a bit off topic but I just checked out your 64458 spreadsheet; in there its saying that a 12V Osram driven at 18 volts puts out 313% of the lumens?

On a couple bike lights I've made recently I've been running 12 Volt MR 11/16's off of my 18 volt Li ion drill batteries. I knew they made the lights much brighter than when run off the intended 12 volts but I was assuming it would only be 50% brighter as there are 50% more volts.
But comparing a 50 Watt, 12 volt MR16 run on 12 volts side by side with a 35 Watt, 12 volt MR16 but run on 18 volts it did seem to me that the 35 watt bulb was 2X as bright as the 50 watt bulb... Can anyone explain why that works that way?

That's because light output vs voltage isn't linear. It's a power function, with exponent ~3.4. Thus, light output ~ V^3.4. If you go from 12V to 18V, you increase light output roughly by 1.5^3.4, or about 4X (~300%).

rickypanecatyl said:

Sorry a bit off topic but I just checked out your 64458 spreadsheet; in there its saying that a 12V Osram driven at 18 volts puts out 313% of the lumens?

On a couple bike lights I've made recently I've been running 12 Volt MR 11/16's off of my 18 volt Li ion drill batteries. I knew they made the lights much brighter than when run off the intended 12 volts but I was assuming it would only be 50% brighter as there are 50% more volts.
But comparing a 50 Watt, 12 volt MR16 run on 12 volts side by side with a 35 Watt, 12 volt MR16 but run on 18 volts it did seem to me that the 35 watt bulb was 2X as bright as the 50 watt bulb... Can anyone explain why that works that way?

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Make yourself a bike light with a 458! I'd like to see that actually, although I don't know how effective it would be having to turn it on and off every 15-30 seconds. :laughing: It makes some massive heat lol.

mrartillery said:

Make yourself a bike light with a 458! I'd like to see that actually, although I don't know how effective it would be having to turn it on and off every 15-30 seconds. :laughing: It makes some massive heat lol.

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I did notice that about the heat Is how long your battery lasts proportional to the lumens as well? IE if a 12 volt, 50 watt bulb lasts 1 hour on a 12 volt, 3.0 amp/hour battery I suppose that the same bulb being driven by a 18 volt battery wouldn't really be 50 watts but would it be 156 watts? (313% X 50). And then the 18 volt 3 amp hour battery would have 50 % more capacity than a 12 volt, 3 amp hour battery BUT drawing 313% as much and so it would last aproximately 29 minutes by comparison? Did I do my math right?

rickypanecatyl said:

I did notice that about the heat Is how long your battery lasts proportional to the lumens as well? IE if a 12 volt, 50 watt bulb lasts 1 hour on a 12 volt, 3.0 amp/hour battery I suppose that the same bulb being driven by a 18 volt battery wouldn't really be 50 watts but would it be 156 watts? (313% X 50). And then the 18 volt 3 amp hour battery would have 50 % more capacity than a 12 volt, 3 amp hour battery BUT drawing 313% as much and so it would last aproximately 29 minutes by comparison? Did I do my math right?

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Use the CPF search. The answers are already there.

No, power consumption vs voltage obeys a different power law than lumens vs voltage.

See this for example.

Go here to download some Excel files on re-rating hotwires.

Justin Case said:

Go here to download some Excel files on re-rating hotwires.

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+1, great info here! A hotwirer's best friend.