Single 18650 cell + XML T6 vs XML L2 vs XML L2 U2 (similar emitters huge gap?)
 

So in reading all this stuff, including the recently mentioned Divine light (I've got the generic from ebay)....I've got a couple questions.

1.) What difference is there in 18650 cells? (I have UltraFire greys that say 5000mah) I notice candlepower forum folks laugh at ANY UltraFire cells. Yet, the grey ones I have work ok for me. I usually give them about 1 hour before I swap a cell. Would better cells provide more brightness in a Cree emitter, or just longer life?

2.) So is there such a spread in single-cell 18650 XML lights? Even just XML T6's (which are considered dinosaur now, right?) rate anywhere from 160lm up to 910lm. How the HELL is that possible?

And in addition, what's the improvement scale going from T6 to L2 to L2 U2. (Is L2 U2 any newer or just another letter/# suffix?)

YouTube touts this as the end-all 18650 light -----> ThruNite TN12 - ThruNite Official Store

My UltraFire '4000mah' (sic) cells power my U2 light for ~45 minutes at full brightness. My Panasonic 3400mah cells power the same light for ~3 1/4 hours at full brightness.

The Good 18650 cost about $9+each

Interestingly substantial!

Any affect on brightness too, or just life?

(btw, CP forum folks talk similarly)

The difference will be:


(1) how long a charge lasts
(2) how many recharges are possible
(3) how long it stays at 3.7 volts before it starts to taper off (related to how long charge lasts, but not quite the same thing)
(4) are the cells 'protected' or not

18650 refers to the physical package, like AAA, but specific to Lithium. Limited experience with 18650, none with Ultrafire, but seen dramatic differences from different manufacturers. dwmckee has answered considerations-differentiators, but I would add DOA (or nearly dead) on receipt, calendar life, cycle life, recharge rate and storage size (mAh), performance at low and high temp.

With respect to Panasonic, I have not been disappointed (knock on wood). Their culture seems to drive conservative performance claims.

Answering #2 - the lumen claims are not at all reliable, and has little to do with the emitter. It's primarily the driver circuits controlling current. The only way to have any clear idea about the lumens and beam quality is look at both candle power forums and budget lighting forums users testing and beamshots.

There is no end-all light. You get lumens, beam quality, throw, or spread. Cannot have them all. That is a pricey light, it better be good.

Most of the cheaper lights you buy aren't run at the maximum drive current for an XML (3A). Usually its 1.8-2.2A. So they are only delivering around 2/3 of what they should be. XML T6/U2/2 whatever is less significant than the huge lack of drive current. This gives extra run time from the cheap batteries and better reliability for poorly designed components and housings.

Batteries seem to run from 1000mAhr to a little over 3000mAhr (2200 seems typical) per cell. You get what you pay for. I've heard of 2 blanks being used in 4 cell packs. :twitchy:

Agreed about lumens ratings, though there are enough tests over on CP that it's pretty hard to deny that they can get anywhere from sub 100 lumens to up over 1000 lumens! (The TN-12 is one of those)

And, actually the TN-12 is the cheapest of the "big 3" in the single-cell 18560 lights. (ThruNite TN-12, Fenix PD35 and the Nitecore P12)

And would coincide with another test (one of the most recent on CP) where a 2014 & 2015 version of the Nitecore EA41 were nearly identical. Odd considering same light by the same mfgr, yet 2014 was a T6 and 2015 was an L2-U2 and not any but about 2 to 3% brighter than its T6 twin. (yikes!!)

Maybe I misunderstood your question: are you asking about the actual manufacturer emitter specifications only, excluding heat sinking, reflectors, drivers, etc? In which case I have no idea.

3% difference in brightness? Who can really see that and does it matter? I suspect a dusty glass lens can cause more loss. Is you approach to this more of a detailed and technical discussion of emitters or a general discussion of practical flashlights for different uses and environments? Knowing which direction you are going might help provide the information you are looking for.

You can get the xml data sheets from Cree. They tell you how many lumens for T6/U2 etc. Also you can find info on lumen droop as the led heats up (Cree used to quote output at 25C but usually a more realistic 85C).

Just looking for a really great light and a general feel for how generic late-model Crees work. For example, one light can go from T6 to L2 or L2-U2 and jump a couple hundred lumens vs how another light (like the Nitecore example I gave) don't increase a bit. I've already got a $20 ebay (basically that Divine light precisely but less graphics) and it's not bad

I should just get a dedicated bike light but consensus is that there are 2 options:

1.) Bontrager 700 (great light but gets hot & no swappable battery) $100

2.) Cygo Expilion 850 (great light w/ swappable battery but they're expensive & mount is not so great) $109 + $32 for extra battery

Thus I search for a more generic option but WITHOUT an external battery pack. I ride w/ an old racer who loves his $26 amazon dual-cree T6 but has an external battery pack. Everyone else I know has older NiteRiders, Serfas, etc.

What about the Lezyne Super Drive XL. Claims 700 lumens and I just picked up two for presets from Amazon for $80 each. Pretty decent mount for handlebars and comes with replaceable 18650 cell.

Hahahahaha! The maximum 18650 battery is 3400 mAh. Any batteries that claim to be higher than that are garbage. Because of the potential dangers of Li-Ion batteries, I recommend purchasing brands that are known to be reputable and from reputable sellers. My first 18650 were from DX, but I now buy Panasonics only and from reputable sellers in the US. There are plenty of threads about what batteries to purchase and there is Flashlight information this site which has a lot of reviews on batteries and chargers and flashlights.

While battery explosions are rare, they do pose real risk and can cause a lot of damage, so I no longer cheap out on large 18650 batteries or chargers.

Rechargeable Batteries | BudgetLightForum.com
Basic to Advanced Battery Information from Battery University

That is quite possibly the best solution I've seen so far.

1.) Bright! (I consider 700 lumens plenty, though I am reading that that "highest" mode is a little hidden.....aka "overdrive"). Nonetheless not bad. I wish the 700lm time was more than 1:30min and that the 2nd highest (500lm) was longer than 1:40min but with swappable battery....any issues solved!

2.) No worries with 18650. (smart)

3.) Side cutouts too. (Not that it's as good as Light & Motion's Urban series side-light but still an effort)

Just gotta be careful ordering. I was wondering where you found for $80 but there's apparently an older version (500lm max) for $65 and then there's the older kit & newer kit (500lm & 700lm) which are both over $100 on amazon. I'd do just the light itself w/ handlebar mount.

I thought maybe you had to order the spare 18650's from them because they were "sleeved" but that looks like just a storage sleeve. So i cud just pick up some quality panasonics off the web.

Do you happen to know if the light can use most protected 18650 cells? When I chose my flashlight / bikelight I read that sometimes the protected cells are just a hair too long, or even the diameter made them too snug. So much depends on the light itself.

If so, then the Lezyne looks like a pretty good main light. Beam shots show a bit more hot spot than I like, probably similar to my lights, but throw is so important, at least for me, to see what's down the road. I also use a small light on my helmet, about 80 lumen max, but would rather have a very wide flat beam at about 150 - 200 max. Weight, size, wide smooth beam, and runtime are my helmet light priorities.

I used this headlamp for the last 14 months.

This is the Amazon link for $78.77. Amazon.com : Lezyne 1-LED-6-V304 Super Drive XL Headlight : Sports & Outdoors
I just tested it last night with several other 18650 cells and all work fine.
I did a run down test last night on the medium setting and it ran for 3:08 on an Ultrafire cell rated for 3600 mAH. Same test on the Lezyne battery (rated for 2400 mAH) ran about 20 minutes longer. I ran both tests until light went out; it switched to a dimmer setting on its own some time after 2 hours. The medium setting seems plenty bright for night riding.
I really wanted the Lights & Motion because it is US made but it is about twice the price and does not have a removable cell. No removable cell was the main deal breaker. Who the heck wants to be stuck in the dark when the battery is dead? Ability to carry spare cells and charge them in a real and fast charger is a pretty compelling reason to go with the Lezyne. I cannot see why anyone who rides much at night would want a light that has to be removed and recharged without a replaceable cell. I do see why manufacturers like them though; they make you buy a whole second light as a backup instead of just a cheap generic cell.

Agreed! That's why I've stuck to my circa~300 lumens ebay light. It's barely enough but more importantly, I can swap cells & keep going.



I notice that too. Here's 3 different screen shots to give a feel. The NiteRider 750 is friggin' amazing!! I almost don't wanna look at it cuz it's the reason I think people will still go with a non-swappable cell light........

Lezyne SuperDrive XL ---> Lezyne Super Drive XL - Mtbr.com

NiteRider Lumina 750 ---> NiteRider Lumina 750 - Mtbr.com

Lights & Motion (they only had the 500 shown) ----> Light & Motion Urban 500 - Mtbr.com

But here are a couple other considerations ----->

Bicycle magazine's winner the Bontrager Ion 700 (not great, imho) ----> Bontrager Ion 700 - Mtbr.com

The Jet Lite F3 (not as popular, but 1000 lumen claim falls short at 724, yet still looks good) -----> Jet Lites F3 - Mtbr.com

Most of the Fire batteries are junk. I have found that the Panasonic 3400's are the longest lasting. High quality batteries that are rated at 2900 and 3400 are using Panasonic batteries.
Here is an example. Panasonic NCR18650B Protected 3400mAh

Indeed that appears to be the case. (Then all the accusations about whose cell is really "inside") Nevertheless, I think Panasonic 3400 protected cells are a pretty easy decision.

One other issue that has concerned me after a TON of reading on CP forums today.......

All the single-cell 18650 lights there have these crazy step-down issues. And repeatedly one of the main reviewers there touts that there's simply no way a 18650 cell light can hold claimed max lumens for over an hour. (or even half that?)

Yet, mtbr forums 2015 light shootout shows the very opposite. All max ratings appear to be held for very close to their full-length of claimed time. (most OVER an hour).

What gives???

To put some numbers to it, the UltraFire cell I ran went 3:08 to lights out and it cost about $6.
The Lezyne cell ran 3:28 until lights out and sells for $20 ish.
The Lezyne cell cost 3x the 'cheap' cell and was only 10% longer in run time.
The cheap cell I do not think qualifies as 'junk'. It ran nearly as long as the expensive cell but was way less expensive. No doubt the better cell ran a little longer, but not 3x as long to go along with the 3x price.

I have some Panasonic cells also and have not tried them in the rundown comparison but will do so soon. I will say that at least some of the cheap cells do have utility and are a bargin for what they cost, even if they are not as good as the top performers.

It's been a while since I posted here but I have some info that may help or confuses you more. There is a lot of factors here that will affect what you have read. A light can drop lumens when the light heats up. This is especially true in cases with the small lights with LED that are driven hard. It is a waste as all those power are wasted to creating heat and also increase the possibility of damaging the light. Some manufactor will overcome this by using auto step down programed into the driver. One company that does this is the well known Zebralight. Lights that does not have this feature will simply have less lumens after several minute from the initial power on. During this period, you will notice some decrease in light intensity. This process will continue until there is an equilibrium of the heat produce from the emitter and the amount the heat will dissipate from the flashlight body.

Another factor that affect the total lumens coming out of your flashlight can be cause by the batteries. A freshly charged 18650 can yield a higher current load, however it will decrease as the battery get run down. The internal resistant of lower quality battery will affect how well the flashlight can hold lumens regulation. This is a less problem with flashlight that are driven in the lower range since the current draw from the battery is less. If you study search for folks who has charted out various battery, you will notice how the better battery can affect overall performance under a heavy load.

One of my biggest gripe about the ultrafire is the inconsistency of the battery. I order many from DX and most are generally ok with light to medium load application. However there are several bad batteries that stand out from the rest of the batch. Generally speaking, that is ok since I can just simply recycle those in the waste bin. The biggest issue is if you are planning to use those in flashlight that are not single cell. Not knowing how if the cell are equal in spec can lead to some serious issue such as injuries. In this case, it is better to just use better know quality cell that are more consistent with the specification.

Last thing worth mentioning here before I stop yapping. Generally most light tested at MTBR forum are multiple battery cell light. This means that the voltage and current the battery pack can hold better regulation throughout the duration of the light. There will be less current sag from the pack and also the voltage will remain above the 6 volt mark. Keep in mind that Led need some minimum FWD voltage to stay bright. It is something like 3.35v for a U2 if driven at a specific current. Multiple cell pack will have no issue holding this spec but a single cell flashlight will drop out of this requirement after a certain amount of runtime. This is even more so if one was using very cheap flashlight battery............Ok hope I did not confuse you much.

Actually, a lot of the lights for the 2015 shootout are single-cell. Thus my interest. It's pretty amazing that (for something like the PD35, TN12, etc.) they don't have those step-downs better regulated like the bike lights. (shrug)

And, I definitely agree about the cell quality.

After reviewing the "lumens per $" graph on mtbr.com, I noticed the Fenix BC30. That is a pretty impressive light. My only concern is that I can't tell if the beam pattern would be to my liking or not. Some say it's great. Some say it's too floody. I think the temp would be great because I like that it has a warmer tone than most. It'd be slightly heavier than a single-cell but the screen shots on "hi" (1200 lumens) are ridiculous. It'd be like having 2 car headlights on the front of my bike.

???

P.S. Link to the BC30 review including beam shots, etc. -----> Review: Fenix BC30 - Mtbr.com