P60 sized led drop-ins (part 3)

twl

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Not sure if this the right place to ask but;
Going to pick up a Malkoff MD2 w/ a M61w to use for a duty light. In the past I've always used primaries but I'm contemplating a single 18650 simply because the MD2 fits it. The pros of this are longer runtimes vs CR123 x2 and lower cost over time. The cons are the initial cost (battery & charger) and improper charging/discharging hazards. Brightness/output should be the same. Do I have it right or no?

The M61 will not remain in regulation for very long on 1 x 18650. It will start out regulated, but after a short time, it will drop off regulation and begin a very long slow taper of brightness reduction, sort of like the old unregulated lights which slowly got dimmer over hours and hours of time.
Other than that, there's no problem with doing it. You just have to be comfortable with the majority of the use being below the regulation limit, and in direct drive.
 

P_A_S_1

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Hmm, OK. Thought it would be similar, the full out put runtime (2hrs.). Thanks.
 

Hondo

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I'm going to disagree with twl's answer here. The older M60 had a higher low voltage at which it dropped out of regulation. We are talking about the current M61 which is rated down to 3.4 volts before losing regulation. That is one dead 18650, needs changing anyway. But you will not be left in the dark, it will still give diminishing light for a long time.

I would say, not that I have run my M61 down to the bone, I charge fairly often, that your expectation is pretty much spot on.
 

P_A_S_1

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OK, so let me ask this. If the M61w and M61lw both have the same voltage range 3.4 - 9 and the difference is the amount of energy they draw (650ma vs 300ma) then choosing one over the other wouldn't matter in this regards because the voltage rating is the same. One just depletes the battery quicker. Is that correct?
 

Hondo

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Correct, just a runtime vs brightness tradeoff. One could make an argument that at higher currents there is more voltage sag, and therefore you will drop out of regulation sooner. But at these drive levels, I don't think you'll find that significant.

BTW, those currents are given at 6 volts. With an 18650, it will draw more amps to get the same power to the LED.
 
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P_A_S_1

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OK, Thanks. Have a MD2 w/M61w on the way and will eventually pick up 18650s and a charger after some more reading. Appreciate the help.
 

tam17

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Are there any lumen and candela measurements of Solarforce proprietary "LC-1" (XR-E Q4) and "LC-XML" (XM-L T6) single-mode drop-ins when powered by 1x18650? Official Solarforce info is "for reference only":thumbsdow

Cheers
 

P_A_S_1

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In regards to the M61w and 18650's, I have the light and the batteries but am still waiting on a charger/volt meter from Cotonpickers so I've yet to do any real testing. I'm not sure the condition the batteries come in from the factory (partial charge, full charge) but just putting them in the MD2 to test I see no difference in high output in comparison to two cr123s. Low on the other hand is dimmer but I've read that's normal. I like the set up with the MD2 and 18650s and I'm looking forward to doing a few tests on runtimes and output.
 

Sam Z

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I have an old Surefire 9P gen 1 or 2, it is 3 CR123A size. I purchased the Solarforce 3.7v-8.4v CREE XML 3 Mode drop in as well as the Solarforce L2-S5 tailcap and the Solarforce A001 Type III HA Head. The voltage on the drop in will be able to handle 3 CR123A correct?
 

fgials

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What P60 pills are yall using in the Solarforce L2M or Vital Gear FB1 single cell bodies but can still be run if you wanted to use in a 18650 body or 2 primaries?
 

Hondo

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"I have an old Surefire 9P gen 1 or 2, it is 3 CR123A size. I purchased the Solarforce 3.7v-8.4v CREE XML 3 Mode drop in as well as the Solarforce L2-S5 tailcap and the Solarforce A001 Type III HA Head. The voltage on the drop in will be able to handle 3 CR123A correct? "

That voltage range is for one or two Li-Ion or two CR123A. Three CR123A's is 9 Volts, and beyond the design range. From a practical point, it may not cook the electronics when you first turn it on, it is not WAY over the design limit, but I would not expect it to handle it well for any length of time. You want a module with a voltage range of at least 9 volts for the upper limit for 3 CR123A's.

On the other hand, two 17500's would be just right for that module, and give rechargable economy. They fit in the same space as three CR123's, but can be a bit snug on diameter depending on the light, some people will end up taking the label off of the cells to get them to fit. If you have never used Lithium Ion cells, read up and use good common sense and equipment if you decide to go this way. Much cheaper in the long run, and allows you to start any given task with a full charge without generating a bunch of partially discharged cells.
 

Sam Z

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Hondo thank you for your reply!

I will definetly look into the 17500s, that is the exact type of answer I was hoping for Thank you again!

I am new to this whole drop in thing, I was ready to write my 9P off.

I will also keep an eye out for higher voltage drop ins.
 

Sam Z

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On the other hand, two 17500's would be just right for that module, and give rechargable economy. They fit in the same space as three CR123's, but can be a bit snug on diameter depending on the light, some people will end up taking the label off of the cells to get them to fit. If you have never used Lithium Ion cells, read up and use good common sense and equipment if you decide to go this way. Much cheaper in the long run, and allows you to start any given task with a full charge without generating a bunch of partially discharged cells.

Hondo few more questions: voltage wise on the 17500, 2 x 3.7v =7.4v would this give me the full power or full potential of the LED itself? (max. lumens)

will the 0.6v difference on regular CR123a reduce the life of the unit drastically?

does a rechargable battery effect the mode settings in a drop in? (I bought the 3 mode)

Thank you!
 

RandomFlyer

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"I am new to this whole drop in thing, I was ready to write my 9P off."
"I will also keep an eye out for higher voltage drop ins."


Sam,
Check out the Malkoff Devices M91 series drop-ins. I upgraded a Surefire Z3 (also a 3 cell light) with the warm tint version and it works great.
 

Hondo

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Hondo few more questions: voltage wise on the 17500, 2 x 3.7v =7.4v would this give me the full power or full potential of the LED itself? (max. lumens)

will the 0.6v difference on regular CR123a reduce the life of the unit drastically?

does a rechargable battery effect the mode settings in a drop in? (I bought the 3 mode)

Thank you!

The module is rated for cells at full charge, which is 4.2 volts, so 8.4 for a pair. You should expect full brightness and normal mode operation on that module, since you will always be running near the high end of it's input range. I can't say what will happen if you exceed that range, but common sense says that if it can still work fine at that voltage, the manufacturer would have rated it for the wider voltage range.
 

Sam Z

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RandomFlyer, thanks for the suggestion, but a $70 price difference is hard to fathom for a new guy...

Hondo, common sense prevailed and I obtained a couple 17500s and am happy with the results. Thank you for leading me in the right direction. Your advice and info have been invaluable.
 

robert.o

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lighthound still has them for sale

I've been told that Solarforce have discontinued the red drop-ins. They also have disappeared off their website. But the blue and green ones are still available. Can anyone confirm or deny?
 

AutoTech

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I was really pleased with my solarforce XML drop in. It's got a great smooth beam, much better than a lot of smooth reflector flashlights I have used. Can't go wrong for the money.
 
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