SureFire M6 rechargeable options – SHOOTOUT
At long last, I have managed to get around to doing a series of shots of some of the various possible M6 rechargeable options. I have been planning to do this for a while, but something always seemed to get in the way.
Just getting all the gear together took some time.
The bulbs/LAs can be split into 2 groups: those that work with two Li-Ion cells in series (2s) and those that work with three Li-Ion cells in series (3s).
· Osram 64250
· WA 1111
· Philips 5761
· WA 1185
The MNxx bulbs:
The 64250, 1111, 1185 and 5761 bulbs require a Fivemega MN bi-pin socket for the M6.
3 bi-pin bulbs in FM holders are shown here, together with the Lumens Factory HO-M6R:
Below is a closer look at the bi-pin bulbs. The physical size of the glass envelope is important, as it determines whether or not the bulbs will actually fit through the reflector hole in the KT4 turbohead. The WA bulbs are small and compact, whereas the Philips and Osram bulbs are much larger. My 5761 did fit OK, but the Osram 64250 did not fit, so it could not be tested (I tried 3 of them, but they were all the same). With 5761 bulbs, there have been reports of variations in bulb sizes between one batch and another, so some may fit and some may not. The same may be true for 64250s.
Those filaments are interesting too. If you compare the WA1111 and WA1185, you can immediately tell which is the higher-voltage 1185 – the filament coil is longer. The 64250 and 1111 filaments are almost exactly the same size and configuration, indicating very similar performance. The 5761 filament is a larger-diameter coil of thicker-gauge wire, and you can tell just by looking at it that it is going to absorb a lot more current than the others.
The stock battery configuration for the M6 is 3s2p (3 series, 2 parallel) CR123A primary cells in the MB20 holder.
Rechargeable battery options available are as follows:
2s Li-Ion cell packs:
· 2s 18650 (mdocod’s 2x18650 holder)
· 2s2p 14670 (Fivemega black (7.4V) 4x14670 holder + plastic insulator cap needed)
· 2s ‘C’ Li-Ions (with Fivemega 2C extender)
2s2p 14670 and 2s 18650 should in theory perform identically, having the same capacity, although the 2s 18650 will be a cheaper and better option. 2s ‘C’ gives increased capacity. However there is the disadvantage of the 2C extender lengthening the light by ~17 mm. The 5761 (and the MN21 Li-Ion option) should be used only with 2x ‘C’, as the current draw at ~5A is too much for 2s 18650 except in short bursts.
However, the increased discharge loads possible with Lithium Manganese (Emoli) cells, available in 18650 size, present a workable solution for M6 owners who want to use the 5761 and are not worried about short run-times.
3s Li-Ion cell packs:
· 3s2p RCR123 (in the SF stock MB20 holder)
· 3s 17670 (Fivemega 3x17670 holder)
The 3s 17670 set-up will out-perform the 3s2p RCR123s.
Here are the battery packs:
Please note in the above pic: there is a home-made plastic cap (made by me) that fits over the +ve end of the 4x14670 holder. This is needed to prevent the +ve terminal shorting on the M6 body. It can be seen that the 3x17670 holder already has an insulating disc fitted.
The Fivemega 2C extender comes with a plastic sleeve to take the 2x ‘C’ Li-Ion cells, pictured above. Here is a photo of an M6 body fitted with the Fivemega 2C extender, next to a stock M6 body:
One problem with comparison shots is trying to make sure the lights are all pointing at exactly the same spot in each successive photo. I decided I needed a solid cradle, similar in concept to a shooter’s bench-rest, to hold the lights.
Mrs DM51 very kindly made an involuntary donation of a redundant chopping board for this purpose. When I realised the tremendous scientific (non-culinary) potential of this chopping board, I pointed out to her at some length that it had lethally unhygienic cracks in it, suggesting that from now on she should instead use one of her other boards, as they looked very much less conducive to salmonella, botulism, or other alarming and gruesome gastro-intestinal afflictions. Anyway, she has not said anything so far about the board going missing, and with a bit of luck she won’t notice.
I glued a 45° wedge to it, and a right-angle join from a box to that, to act as a channel to lay the lights in. This is the result:
Anchored firmly in place, it ensures each light points at the same spot.
Adamlau did an excellent series of shots in an urban setting, so I chose a rural one.
The target here is the large integrating tree on the right in the main photo. As marked on the photo, it is 135 yards (400 feet) from the “firing point”. That is a good distance away, and it takes a powerful light to throw that far to any useful effect.
First, here are pics of the MNxx bulbs that were tested. These are small versions of the photos, for ease of comparison side by side. Larger copies (600 x 460 pixels) can be found in post #2 – they may be useful for making “gif” rotating shots.
On the left in each case the bulb is running on primaries, and on the right you see the same bulb running on Li-Ions.
In each case above, the primaries were 3s2p in the stock MB20 holder, with the exception of the MN61, which was running on 4s in a 2x18650-size Leef body. The rechargeable configurations were as shown.
Note that the MN16 seems brighter than the MN61 – this should not be the case. It is mostly because the MN16 is designed to run of 3 primaries, not 3s2p. With 2 banks of CR123As, there is far less voltage sag, so the MN16 is being overdriven. I also have to confess that the 4 cells used for the shot of the MN61 may not have been quite as fresh as the ones in the M6 bodies. That MN61 on primaries is the 1 shot in this series which is possibly suspect. All I can say is that it looked pretty bright; but the MN16 was brighter. See how the MN61 performed on Li-Ions, though!
Now it gets more interesting, as we add in some other bulbs. Time to settle a few scores!
Here are a few pairs that make interesting comparisons:
HO-M6R vs. MN20 (primaries)
HO-M6R vs. MN16 (2x 18650)
HO-M6R vs. MN21 (primaries)
MN21 (primaries) vs. WA 1111
MN21 (primaries) vs. MN61 (3x Li-Ions)
MN21 (2x ‘C’ Li-Ions) vs. 5761 (2x ‘C’ Li-Ions)
WA 1111 vs. WA 1185
5761 vs. WA 1185
Before finishing with the beamshots, I would stress again that the target is a very large tree, about 80 feet high, and it is a fair distance away – 135 yards, or 400 feet! All the photos above are with the camera on ~2x zoom. Just to illustrate this, here is what the WA 1185 beam actually looked like without the zoom:
You may already have formed your own conclusions from the photos above. Below are some of my thoughts.
The first thing that must be realised is that the high-output (HOLA) Surefire MN-series bulbs used with Li-Ion batteries will suffer a reduced life.
As you can see from the comparison shots above of the MN16, MN61 and MN21, they are much brighter when running on Li-Ions than they are on primaries.
This is nice, but unfortunately it comes at a cost, which is a shorter bulb life. The greater the increase in brightness, the more drastic the effect on bulb life. The MN15 and MN20 will probably do OK as they aren’t driven so hard, but those 3 HOLAs are not going to last very long at all. The cost of running your M6R on Li-Ions with Surefire HOLAs at around $30 a pop may end up being as expensive as feeding it with primaries. Sorry guys, but there’s no way round that one.
The lifetime of bi-pin bulbs is better documented. When over-driven, as here, these bulbs will have a lifespan in the region of ~10 hours, but they are a lot cheaper - $9 for a WA1111, and only $5 for a WA1185. And a mere $3 for a 64250 - if you can find one that fits!
Star ratings given below for practicality are awarded for various reasons, the principal one being anticipated bulb life.
Bulb performance and ratings
The MN15 confirmed its value and utility. It draws an economical 1.15 amps. I have been using it quite a lot, but until now I had not done a comparison at distance, and it is at distance that quality shows up. You only have to look at the photos above to see how well it performed. As can be seen here, and contrary to reports made elsewhere, it works well on 2x Li-Ions. Either way, with primaries or rechargeables, the MN15 is a very good option for anyone requiring a working light with long run-time. It only gets 1 star here for output, but that tree is a long way off, and the standard in this shootout is very high indeed. There can be no doubt that this is an extremely useful bulb.
The MN20 is a fine all-round bulb, drawing 2.45 amps. It is a good general purpose bulb for the M6 for both primaries and Li-Ions. With this bulb, you have enough light for almost all uses.
The MN16 gives a startlingly better performance than the MN20, beating it on output. It draws 2.6 amps, so it can be expected to be brighter, and it is. However, it is clearly over-driven on 2x Li-Ions, and its life will suffer severely.
The MN21 is an amazing bulb, but unless you have an endless supply of CR123A primaries, it really isn’t very practical. It draws 4.9 amps. People probably fire it up from time to time to amaze their friends, but even for that purpose there are more impressive options. Using it with the FM extension and 2x ‘C’ Li-Ions was spectacular. However this is over-driving it hard, and bulb life is likely to be very short. From cold, I found it required double or triple-clicking to start it. For all these reasons I do not consider it a practical option.
The Philips 5761, like the MN21, is a high-current bulb, drawing 5.4 amps. It needs the FM 2C extension, as it should not be used with smaller Li-Ion cells than ‘C’ size. There are reports of some batches of 5761s being too large to fit through the KT4 reflector hole; certainly, it is a close fit. The filament sits up higher than the WA lamps, so ~1mm of shims are required on the base of the bi-pin holder. As if all that wasn’t enough, it needs several clicks to start. Unless you intend to use LiMn (Emoli) cells in a 2x18650 holder and you don’t mind extremely short run-times, it is not worth considering this bulb for the M6 (in my opinion, anyway).
The MN61 is dazzling. On 3x Li-Ions it outperforms the MN21 on primaries. However, it is seriously over-driven in this configuration (3 amps measured) and there have been several reports of it instaflashing. Even where this does not happen, bulb life is going to be short and consequently expensive. Sadly, it does not seem to be a very realistic or reliable option. On output it is really 4˝ stars, above 4 but not up to 5.
The WA 1111 is a great bulb. With 2x Li-Ions I measured it drawing 3.6 amps. Its output is very similar to the MN21 on primaries, as I have shown in another thread, and it uses less (and free) power. It is a very good option indeed, with useful run-time on 2x18650. It is no surprise how good this is. It is a very fine combination for the M6.
Some people are lucky enough to have an Osram 64250 that will fit into a KT4; however mine did not. I would expect it to perform almost identically to the WA 1111 (cheaper, too – it is $3 instead of $9). If you are really skilled at grinding glass down with a dremel, you might be able to shave the sides of these bulbs down just enough to fit, and then you will be in business!
The Lumens Factory HO-M6R was the best surprise of this shootout. It draws 2.1 amps from 3x Li-Ions – that is Lumens Factory’s own figure, and it proved accurate on measurement. This means it can be used safely with 3s2p RCR123 Li-Ions in the stock MB20 holder; however it will perform better with 3x17670s. The HO-M6R has always been described as being “somewhere between the MN20 and MN21 in output”. Well, we can now officially scratch that description as inadequate. It stomped the MN20, and it gave the MN21 a very good run for its money. It was a far closer thing than I thought it would be. It has a tighter beam, and I think it actually out-throws the MN21. Throw is a feature of Lumens Factory bulbs, and this is a superb thrower. I knew it was good, but it took this comparison to show just how good it really is.
Finally, as expected, and as can be seen from the photos, the WA 1185 with 3x17670 was the winner in the power contest. Drawing 3.3 amps, it matches the 5761 for output, and is a much more practical alternative if sheer power is what you want.
I hope this thread is some help to those deciding what to run in their own M6.