Rechargeable M4 worth the $$$????

[senna94]

I just purchased a Surefire M4 today on sale at Gander Mountain for 249.99. I must say that this is one great light!!!!!!! It is as if my Surefire A2s big brother just arrived!!!!! I am considering converting it to a rechargeable with the following set up.

1- Leef 2 cell 18650 body @ 59.99 + 1 -Leef Tailcap for said body @ 39.99 + 2 - 18650 cells @ 12.99ea + 1-Surefire MN 16 lamp @ 31.00 is a grand total of $157.00 to convert to rechargeable. I already have a charger for the cells thank goodness. In doing the math further I would have to replace the 4 primary cells 39 times @ $1.00 each per cell from amondotech just to break even. At that rate I could replace the primary cells twice a month for a year and a half!!!!!! Just wanted to get some input as to whether or not you guys think it is worth doing the conversion?????

Thanks,

Paul

P.S.: I primarily intend to use it around the house to check out noises in the middle of the night.

 

[depusm12]

You actually could use the tail cap from the M4 instead of buying another, unless you just prefer the Leef clicky tail cap. IMHO it is worth it. I have a SF M3T that I got with a LuxIII tower module and 17500 Li-Ion's. I also bought a fivemega bi-pin M adapter and some Carley 1057 bulbs and a Seoul P4 tower module. I use it often at work to reach out and touch a particular area.

 

[adamr999]

If you want a light that is always ready for use, stick with primaries.

 

[defusion]

and forget the leefbody, and go for 2x17670's.
unless your starting from scratch with a build, like KT4+leefbody+tailcap, i wouldn't replace the body.
and i would consider getting a bulb from lumensfactory, like the EO-M3T. great quality, and brighter aswell.

so 2x17670 = ~$28 (incl. shipping)
LF EO-M3T = ~$25 (incl. shipping)
and thats it!

Cell configuration: 2x17670

Bulb Options:
SF MN15: 9.5W, 80 min, 155 lumen
SF N2: 9.5W, 80 min, 155 lumen
SF MN16: 20W, 30 min, 370 lumen
SF MN20: 19W, 30 min, 310 lumen
LF HO-M3T: 15.5W, 40 min, 310 lumen
LF EO-M3T: 18.5W, 30 min, 350 lumen

as you can see, there's other options for bulbs aswell, just choose what you like.

 

[Owen]

You can get the body bored for $20, and don't need another tailcap. Or you could sell the body for about $100 on B/S/T forums, buy your $60 body, and still clear enough for that MN16 bulb after shipping costs.

 

[mdocod]

I like Owens Idea of seling your current body and buying a leef. to re-coup the costs.

Like other have said, no need to replace the tailcap.

Go for either the MN16 or EO-M3T for maximum OOOMMFFF!!!

 

[mooman]

If you want a light that is always ready for use, stick with primaries.

Aren't Lithium rechargables ready to use? They don't lose too much power over time like Nimh's do. Not to mention the rechargables are brighter and last longer than the primaries. I got the setup with 18650's and love it.🙂

 

[senna94]

Thanks for all of your great input and suggestions. I think for now I am going with defusion's suggestion of keeping the original body and use 2* 17670 with an MN16 or MN15. With the money I am going to save I will probably get both lamps. I noticed that lighthound has some magnetic/nylon washers to provide contact points on the 17670/18650 s. Have any of you had the opportunity to try these?

Just a little FYI: I think that Lighthound will soon be carrying Lumens Factory lamps assemblies. I really hope so since the only U.S. dealer we have only carries some of the lamps. I have wanted to order some but really don't feel comfortable ordering from Asia.


Paul
:twothumbs

 

[adamr999]

Aren't Lithium rechargables ready to use? They don't lose too much power over time like Nimh's do. Not to mention the rechargables are brighter and last longer than the primaries. I got the setup with 18650's and love it.🙂

I stand corrected.

 

[trouble]

I'm going the 2x17670/MN16 route with my new M4 as well, it's a good setup that i've used before.

 

[defusion]

Thanks for all of your great input and suggestions. I think for now I am going with defusion's suggestion of keeping the original body and use 2* 17670 with an MN16 or MN15. With the money I am going to save I will probably get both lamps. I noticed that lighthound has some magnetic/nylon washers to provide contact points on the 17670/18650 s. Have any of you had the opportunity to try these?

Just a little FYI: I think that Lighthound will soon be carrying Lumens Factory lamps assemblies. I really hope so since the only U.S. dealer we have only carries some of the lamps. I have wanted to order some but really don't feel comfortable ordering from Asia.


Paul
:twothumbs

Unless you really want to stick with surefire bulbs, consider the EO-M3T and the HO-M3T from lighthound aswell! they are a little bit cheaper, but very well made, and (i believe) more efficient. or go for both a HO-M3T for that little bit more runtime and barely noticeable less output, and the MN16 for high output. i really don't know which would be brighter, the EO-M3T or the MN16, and mdocod's list is just an educated guess, and they are very very close.

 

[senna94]

I was reading in another thread that somebody has used the factory body of the M4 and two single cell extenders so that it will take 3- 17670 cells and use the factory designated bulbs. (MN 60 / MN 61) Has anyone else tried this set up? It seems that while making it longer, it will have a longer runtime since 3 -17670 trumps 2-18650 cells.

Paul

 

[Strauss]

It seems that while making it longer, it will have a longer runtime since 3 -17670 trumps 2-18650 cells.

Paul

Actually, those two cell set-ups provide close to the same capacity.

Typical 17670: 1500mah....x3 = 4500mah
Typical 18650: 2200mah....x2 = 4400mah

😉

 

[defusion]

and the MN60/MN61 can't handle the voltage safely. some have reported it to work, but it is very close to the edge, and i wouldn't expect more then a few hours of bulb life on average.
so costs would climb very rapidly if you have to replace those pesky bulbs every couple of hours.

 

[mdocod]

The 3x17670/18650>MN60/61 is a weird one...

Based on my calculations, I can't figure out how the lamps don't just instaflash. It's really on edge, talking like 5 hours of re-rated life or less or something.

But the fact that it does usually survive is amazing, The MN61 in this configuration, while not reliable, will actually appear as bright or brighter than a M6 loaded with a MN21, and WAY whiter. If only the lamps were cheaper, hehe...

 

[senna94]

The 3x17670/18650>MN60/61 is a weird one...

Based on my calculations, I can't figure out how the lamps don't just instaflash. It's really on edge, talking like 5 hours of re-rated life or less or something.

But the fact that it does usually survive is amazing, The MN61 in this configuration, while not reliable, will actually appear as bright or brighter than a M6 loaded with a MN21, and WAY whiter. If only the lamps were cheaper, hehe...

Is there a way to actually re-rate(calculate) the life of a lamp???? I thought it was more or less an average of what they last based upon multiple burn time tests.

 

[mdocod]

yea, it can be roughly estimated on paper..

lets say they take a 12V lamp, test a thousand units and find that the average failure point is 2000 hours when driven at 12V at the bulb, you can apply re-rating formulas to calculate an estimated life at different drive voltages, and at the same time, estimated lumens, estimated CCT, estimate power consumption etc.. Someone originally posted the halogen re-rating formulas around here awhile back... can't remember who or where it was posted...

anyways... life re-rating is approximately voltage differential to the power of 12. So.... the MN60, was probably designed as a ~9.8V lamp originally, with a ~30 hour life. On 3 li-ion cells, it could easily see 11.5V on fresh cells.
[(9.8/11.5)^12]30=4.5 hours.

in reality, the high pressure lamps in this category might re-rate a bit different, life may be more like ^8 or ^10 or something, depends on the lamp, seems like the more xenon and the more pressure the envelope is under, the less dramatic the exponents are in the formulas for re-rating these things. But re-building a formula for every lamp would be quite the task.

 

[senna94]

yea, it can be roughly estimated on paper..

lets say they take a 12V lamp, test a thousand units and find that the average failure point is 2000 hours when driven at 12V at the bulb, you can apply re-rating formulas to calculate an estimated life at different drive voltages, and at the same time, estimated lumens, estimated CCT, estimate power consumption etc.. Someone originally posted the halogen re-rating formulas around here awhile back... can't remember who or where it was posted...

anyways... life re-rating is approximately voltage differential to the power of 12. So.... the MN60, was probably designed as a ~9.8V lamp originally, with a ~30 hour life. On 3 li-ion cells, it could easily see 11.5V on fresh cells.
[(9.8/11.5)^12]30=4.5 hours.



in reality, the high pressure lamps in this category might re-rate a bit different, life may be more like ^8 or ^10 or something, depends on the lamp, seems like the more xenon and the more pressure the envelope is under, the less dramatic the exponents are in the formulas for re-rating these things. But re-building a formula for every lamp would be quite the task.

WWWWWWWWOOOOOOOOOOWWWWWWWWW!!!!!! Thanks for that excellent information. I never realized there was actually a formula. Does it work both ways? I mean if you under drive a lamp assembly can you apply the same formula??

 

[defusion]

WWWWWWWWOOOOOOOOOOWWWWWWWWW!!!!!! Thanks for that excellent information. I never realized there was actually a formula. Does it work both ways? I mean if you under drive a lamp assembly can you apply the same formula??

yes, but efficiency decreases, so you get less light per watt.
most household lights are made for long life's and can afford a bit less efficiency.
flashlights run on batteries that are pretty expensive compared to just the power that they have in them, therefore it's important to have them be very efficient. to accomplish that, they have to sacrifice bulb life. for flashlights the expected bulb life is therefore around 20-30 hours. overdriving these would result in even higher efficiency and total output, but decrease bulb life to unacceptable levels (to most).

 

[Jeweler]

I have a kt2 turbohead+ 2-18650 leef body + 2-18650's. will this safely power the mn21 bulb or is it better to stick with the mn61 bulb for this setup. A search found the mn21 will work but I wanted to be sure
thanks alot