Surefire lamps on LiFePO4

[chillinn]

Not much fear underdriving 2xCR123A "6V" lamps like MN03 or P60 on one Li-ion 3.6V or 3.7V. Many times it's ok to drive "9V" lamps on 2x Li-ion.

Everyone seems to use 3.2V LiFePO4 (RCR123A) as a direct replacement for CR123A in LED lights.

But does this translate well to incan bulbs?

I would expect MN01 to flash on one LiFePO4 cell. Maybe it would work a short time overdriven before dying. Expect, but don't know.

I have no experience experimenting with P60, P61, P90, P91 and battery chemistry. But I have a precious few R30 on the way that were very difficult to find and outrageously expensive. I'll probably underdrive one on 2xNiMH without fear. But I'd like to dedicate one to run in a KDLitker E6-21700 (that I don't have yet) on a single Generic IFR21700 3.2V 9A 3000mAh (also don't yet have), and I am very very concerned it'll flash or just won't last.

Compared to CR123A, LiFePO4 give way more current with way less voltage sag, but more importantly, even well rested they have slightly more voltage than a new and unused CR123A. P60 aren't hard to find, so I wouldn't mind experimenting on one with 2x LiFePO4, but R30 will be very difficult to replace.

Does anyone know for certain? Has anyone used LiFePO4 cells on Surefire lamps in the last decade or so? I need some old CPF members with experience.

 

[Megalamuffin]

Surefire specifically says about their lifep04 cells that the initial higher voltage can burn out the lamp. Not worth the risk trying to me since all those old lamps are getting more pricey.

I did some testing with the keeppower 3v output rcr123's and they were giving great results in a p60. That p60 flashed on me recently and I think those 3v cells greatly shortened its life. They drive the bulb at max voltage until the batteries run out, unlike 123's that drop in voltage over time.

 

[chillinn]

These cells? I didn't know they existed. I guess the protection limits the voltage to 3V.

Though I have had success underdriving lamps, some CPF members have insisted that under-driving will reduce a lamp's life and darken it prematurely, something to do with the halogen cycle (redeposits evaporated tungsten on the filament slows at lower voltages because of lower heat, tungsten is left on the inside of the bulb and blocks light, dimming the bulb).

But CR123A voltage will sag even at a P60's low 1.13A current, so the "6V" P60 really isn't a 6V lamp at all, more like a 5.4V or 5.2V lamp. At an actual 6V it is overdriven and may have reduced its life. But since P60 lamps are so common and still sold by Surefire, I'd risk using those cells a few more times and not worry about it, maybe get some used ones to save money. But if none of them lasted... stop. A P61 draws more current, at least 2.28A, and might sag the voltage on those cells to survive awhile, if you can stand 120Lm instead of 65Lm. But P61 are not nearly as common as as P60, but still somewhat available. If P61 doesn't survive, you can underdrive a P90, though it would probably be yellower than than the P60, not quite as bright, but maybe, with slightly less runtime at 1.18A. A P91 draws 2.46A, so maybe it would be a better match to those cells, though might as well run P91 on two IMR for more capacity.

There used to be Chinese P60 Xenon lamps that ran on 3.7V and 7.4V, but they all disappeared a few years ago, seemingly overnight. I only have this single one, but I remember seeing them all the time on eBay.

Grabbed this image from AliExpress, no longer available, but here's what they all looked like

Mark still builds them to order in 4 Series 3.7V, 9 Series 7.4V, and one P60 IMR Series 7.4V.

Those 3V limited KP cells are sort of unicorns for incan. Must be intended for two cell 6V LED lights?

I guess I'm not running a 3V on LiFePO4, tho. CR123A or underdrive on 2xNiMH only. If a Surefire P60 doesn't like 6V, I wouldn't even risk running R30 on two alkaline, now.

Thank you for posting, Megalamuffin. Now I know, or at least can assume, 3.2V LiFePO4 will probably instaflash an R30. I'll just get an HO-4 1.6A, or ask Mark to build an HO-E1R 0.8A into a P60 assembly to run in that E6-21700 on a Vapcell F58 INR21700 3.7V 12.5A 5800mAh and call it a day.

 

[Megalamuffin]

For an R30 its definitely not worth the risk.

When it comes to rechargeable options for SF lamps a p90 with 2x 17500s is hard to beat. The keeppower ones run nearly an hour solid. You could always use 16340's in a 2 cell light with p90 if you dont mind short runtime. Either way the p90 is pretty awesome.

 

[chillinn]

What I was going for with R30 1.14A was low light and long runtime. But I have seen Mark accommodate others building custom assemblies, and the HO-E1R 0.8A in a reflector assembly would give better runtime anyway with three times the lumens looking twice as bright, and at a higher color temperature. I just happen to prefer 15-25 lumens even at more current, as it's just the right amount of lumens to see and still save dark adapted vision. But I doubt I'd ever find a 15 lumen 3.7V lamp, so I'll have to settle for 50 lumens. Oh, well.

FWIW surefire.jp still has limited stock of R30 for about $40/pc, but I don't think they ship to US, and if they did it would be pretty expensive shipping, and it doesn't help me here anyway, but maybe it will help someone with a 3P that wants to run primaries.

 

[hamhanded]

2x LFP cells will kill an incandescent P60 instantly. Ask me how I know…

I've used a single LFP cell for a P60 and it works just fine. Obviously dimmer than two 123s… and it will probably soot up quicker.

 

[konifans]

I have always been using Lifepo4 with Surefire lamps.

2 x 16340 Lifepo4 with P90
2 x 26650 Lifepo4 with MN15 on a KT1

They work perfectly and the bulb life will last for a super long time.

 

[chillinn]

Thank you, gentlemen, more info is always better. But, as expected, we're not replacing CR123A one for one with LiFePO4. I was hoping to run R30 on one IFR21700 cell, and there's just no way to do it, unless I order a weird cell with a custom protection circuit that only puts out 2.55V or something. I mean, it's entirely possible, just unlikely to only get a couple. I'd need to order 2000 of them. That's no good.

 

[DRoc]

Agreed with the other members on 6v SF lamps. I literally have hundreds. I've tried many times with various configuration.
I tried using lifepo4 cells years ago. Best succès I had was it would turn on and run. But that was luck. Next few times they simply died.
My greatest success with incan lamps is with a p61 and high quality good condition 18650. It's very nice for guilt free lumes incan
I only have about 60 p61'$ left, so I'd best be using them responsibly 🤪

 

[ampdude]

I don't mess with rechargeable batteries when running 6 volt lamps. CR123A's are cheap enough these days. Two lithium ion's run 9 volt lamps just fine. Sometimes you can get three lithium ions to run a 12 volt lamp well depending on the batteries type/size and lamp you are running.

 

[fivemega]

When you study and learn about designed voltage and current draw of each bulb and voltage drop of each battery under certain load, you will find out answer of all your questions.
Example 1- P60 designed to work with pair of primary CR123A and total voltage of batteries will be abut 5 volts under load but if you use same bulb with pair of LiFePO4, your bulb will see about 6.4 volt which means little over driving.
Example 2- P61 designed to work with pair of primary CR123A and total voltage of batteries will be abut 4.4 volts under load but if you use same bulb with single Li-ion, your bulb will see about 3.7 volt which means little under driving.
Example 3- P90 designed to work with three of primary CR123A and total voltage of batteries will be abut 7.5 volts under load but if you use same bulb with pair of Li-ion, your bulb will see about 7.4 volt which means perfect driving.
Example 4- P90 designed to work with three of primary CR123A and total voltage of batteries will be about 7.5 volts under load but if you use same bulb with pair of 26350 your bulb will see about 7.4 volt which means perfect driving.
Example 5- P60 designed to work with pair of primary CR123A and total voltage of batteries will be abut 5 volts under load but if you use same bulb with 4 of NiMH AAs your bulb will see about 5 volt which means perfect driving.

 

[vicv]

These cells? I didn't know they existed. I guess the protection limits the voltage to 3V.

Though I have had success underdriving lamps, some CPF members have insisted that under-driving will reduce a lamp's life and darken it prematurely, something to do with the halogen cycle (redeposits evaporated tungsten on the filament slows at lower voltages because of lower heat, tungsten is left on the inside of the bulb and blocks light, dimming the bulb).

But CR123A voltage will sag even at a P60's low 1.13A current, so the "6V" P60 really isn't a 6V lamp at all, more like a 5.4V or 5.2V lamp. At an actual 6V it is overdriven and may have reduced its life. But since P60 lamps are so common and still sold by Surefire, I'd risk using those cells a few more times and not worry about it, maybe get some used ones to save money. But if none of them lasted... stop. A P61 draws more current, at least 2.28A, and might sag the voltage on those cells to survive awhile, if you can stand 120Lm instead of 65Lm. But P61 are not nearly as common as as P60, but still somewhat available. If P61 doesn't survive, you can underdrive a P90, though it would probably be yellower than than the P60, not quite as bright, but maybe, with slightly less runtime at 1.18A. A P91 draws 2.46A, so maybe it would be a better match to those cells, though might as well run P91 on two IMR for more capacity.

There used to be Chinese P60 Xenon lamps that ran on 3.7V and 7.4V, but they all disappeared a few years ago, seemingly overnight. I only have this single one, but I remember seeing them all the time on eBay.

Grabbed this image from AliExpress, no longer available, but here's what they all looked like

Mark still builds them to order in 4 Series 3.7V, 9 Series 7.4V, and one P60 IMR Series 7.4V.

Those 3V limited KP cells are sort of unicorns for incan. Must be intended for two cell 6V LED lights?

I guess I'm not running a 3V on LiFePO4, tho. CR123A or underdrive on 2xNiMH only. If a Surefire P60 doesn't like 6V, I wouldn't even risk running R30 on two alkaline, now.

Thank you for posting, Megalamuffin. Now I know, or at least can assume, 3.2V LiFePO4 will probably instaflash an R30. I'll just get an HO-4 1.6A, or ask Mark to build an HO-E1R 0.8A into a P60 assembly to run in that E6-21700 on a Vapcell F58 INR21700 3.7V 12.5A 5800mAh and call it a day.

Kaidomain has them still. I just bought 4 of them 6 months ago. They're like $3 each and last forever

 

[chillinn]

Kaidomain has them still. I just bought 4 of them 6 months ago. They're like $3 each and last forever

fivemega inadvertently turned me on to them about a month ago. I'll be making a large Kaidomain order that includes some of those and other things too when finances loosen up a bit. I overextended myself a couple months ago, but it gets better every month. I'll be out of the layaway by summer with a few amazing incans.

Right now, I'm still dreaming of a firm that designs, provides and installs custom battery circuits so I can ask for a circuit with only LVP and voltage limiting to 3V (more like 2.55V, where one CR123A sags on 1A), like these, without the built-in charger, for something like Vapcell F58 INR21700 5800mAh, so I can run an R30 in this for 5 hours (probably a lot more than 5 hours considering the voltage limiting), and not worry about flashing the lamp or damaging the cell from overdischarge. Maybe a place like this could fulfill, but I'd need something with no minimum order, as I'd probably never need more than 4-8 cells for two lights. Occurs to me if there were such a thing as NiMH 21350 cells (like a 1/2 B cell?), that would get me there, or nearly, also.

 

[chillinn]

Almost mildly interesting, there is a primary 3V cell called a duplex, or 2R10 (IEC) with a diameter of 21.8mm and a length of 74.6mm, close enough to 21700. Here is an example. It is really two 1.5V cells in series, thus the name "duplex." They are hard to find, really expensive, don't have a lot of capacity (somewhat less than an AAA primary), and there are 2R10 to CR123A adapters that exist, which is pretty smart if anyone that requires a 2R10 cell, as CR123A won't leak like alkaline or duty cells, and they have considerably more capacity than duplex cells.

Anyway, my wonder is just what the heck size cells duplex are constructed out of.

But this is all pretty silly, as even if I could find that size cell in NiMH, and two fit in the E6-21700 host, they would have no capacity, and I'd be far, far better off ordering a standard high capacity 21700 cell with a custom 3V limiting circuit, if I could find an outfit that could provide such a thing.

 

[M@elstrom]

CR123A's are cheap enough these days.

These cost around $10+ AUD in local stores, how cheap are they sold for in the US?

 

[chillinn]

These cost around $10+ AUD in local stores, how cheap are they sold for in the US?

If you buy from a local drug store, that's about what they cost here, or more. Don't do that. Battery Junction has them for US$1.10/pc for 50 pieces plus shipping in US. These PKCell are about the same price per piece for 50 pieces Down Under.

 

[Lips]

This thread needs to be closed, costing me money!
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Product	Model	Quantity	Price	Total
KDLITKER 20mm 6A Forward Clicky Switch Module (2 PCS)	S028925	1	$2.78	$2.78
KDLITKER 16mm Forward Clicky Switch Module (2 PCS)	S028827	1	$2.78	$2.78
3.7V 12W / 15W Xenon Bulb Drop-in (Dia. 26.5mm) - Output Power: 15W [S028305]	3.7V Xenon Bulb Drop-in	2	$3.39	$6.78
7.4V Xenon Bulb Drop-in Module (Dia. 26.5mm) - Output Power: 15W [S024191]	7.4V Xenon Bulb Drop-in Module	2	$3.36	$6.72
9V Xenon Bulb Drop-in (Dia. 26.5mm)	S024189	1	$3.36	$3.36
KDLITKER P6-XPLHI Cree XP-L HI 800 Lumens 3V - 9V LED P60 Drop-in Module - KDLITKER-E6: LED Drop-in Only - Mode Arrangement: 2-Group Modes - Reflector: OP - Color Temp.: Neutral White 4000K	KDLITKER P6-XPLHI Drop-in Module	1	$11.99	$11.99
KDLITKER P6-NIC Nichia 519A 800 Lumens 3V-9V LED Drop-in Module - Reflector: OP - Color Temp.: Neutral White 4500K .. - Mode Arrangement: 2-Group Modes - KDLITKER-E6: with KDLITKER E6-217..	KDLITKER P6-NIC Nichia 519A	1	$23.99	$23.99
Sub-Total:	$58.40
Free Standard Airmail Shipping:	$0.00
Coupon (blf):	$-1.12
Total:	$57.28

 

[M@elstrom]

If you buy from a local drug store, that's about what they cost here, or more. Don't do that. Battery Junction has them for US$1.10/pc for 50 pieces plus shipping in US. These PKCell are about the same price per piece for 50 pieces Down Under.

That is pretty cheap, I had seen some online at around $6 each but figured rechargeable to still be better value overall.

I have noted these cells are used in some Wireless PIR detectors...

 

[chillinn]

but figured rechargeable to still be better value overall.

I'd say it's a safe bet you figured correctly, but the only rechargeable cells that give only 3V (that I know of) are P1634U1, and (roughly) a couple of NiMH or NiCad. This now has me considering abandoning dreams of running a 3V lamp in the E6-21700 with a mythical 3V 21700 and instead using a E6s 2x 18650 host, or Seraph SP-9 w/ extender, or if I can source one, LeeF C/P 2x18650 body, with two NiMH 4/3A cells to get decent runtime with a 3V R30 lamp, hopefully over 3.5 hours of 20ish incan lumens.

This is way too complicated when an 18mm E body filled with N36 topped with an Elite head running MN02 standing on a z68 will probably give me 7 hours of 18ish incan lumens, but I am determined to use the R30 that found their way to me. Maybe I should just get a 3P copy, those 3V KeepPowers and/or a box of CR123A and call it a day. It's the F58 and the fact that a 21700 P60 host exists that keeps be vacillating: if I could limit the voltage from the cell to 3V, I could get at least 5 hours of R30 runtime in a pocketable setup, compared to an hour and a half with this monster of likely too much brightness and heat. Maybe someone can dissect P1634U1 and graft the circuit to F58 for me.

I have noted these cells are used in some Wireless PIR detectors...

PKCell doesn't get much love or notice at CPF, but they are name brand, get used in a lot of retail products, and HKJ gave glowing reviews to various formats of the label that he tested (bearing in mind that not all he tested were high performance cells). Amazon reviews are good, and some Redditors have espoused the virtues of the label as well. I figure with primary CR123A cells in single cell lights, the risk (of possibly dead or dangerous cells) shouldn't generate too much anxiety for reasonable current applications.