Even in a place with no power (where you'd probably run it on low nearly all the time) you'd likely only need a cell a week - allowing 2 cells a week you'd likely be fine. And that'd allow a fair amount of using the throw and more power. In Shetland (where I worked in 1989) you'd need more. At this time of year you need artificial lighting just about all the time, it never really gets light in winter. Or dark in summer.
I note some of the more expensive torches boast regulation.
The effect of regulation is that the LED supply voltage is closely controlled at a level somewhat below what the batteries can deliver when (say) 50% discharged.
I don't know how this voltage is decided, particularly if different batteries are to be used, but I suppose the specs call up a specific battery type with known discharge rates.
The thing I don't understand is how can torch LED's stand the unregulated battery voltage variation as the batteries discharge?
The conventional wisdom is that a current limiting resistor is used which I suppose is a poor mans regulation.
Even so the reported differences in brightness over a supply current range varying by around 100% (0.9 amps to 0.5 approx) do not make much sense, it's almost as if the higher current is "wasted". Do we have an electronics specialist who can shed an accurate insight on this?
Peter O
Thanks for the review: Can the drop-in included with this light be run off of 2xAA lithium cells?
The quoted voltage range is 2.7-4.2V
Depends how much the voltage drops under load. If it does, I'd not expect it to run for all that long till the voltage dropped below 2.7V. It also depends on how the driver handles low voltage. Since it is intended for use with a single 18650 and 2.7V is the voltage at which protection circuits are supposed to cut in, it may be that it will run happily to below that. Or it may be that it will cut out at that voltage to prevent the cells from becoming over discharged.
I will drop it into an L2r and try it with alkalines and NiMH tonight to see what happens. Lithium primaries here are considerably more expensive than genuine Eneloops so I don't use them.
Don: Thanks in advance for trying that, looking forward to the results.
If you happen to have a SF L2-ECR (CR123 extender) around can you also verify it threads on the 504B? That is how I would be using it with 2xAA if the driver works with the lower voltage.
Tried it in that configuration. It does light up. Just. Not worth the effort IMO.
Here's a beamshot. It's a Solarforce L2r on the left running on 2 NiMH AA with a Solarforce low voltage R2 single mode dropin. On the right we have the WF-504B with the extension from the L2m and 2 AA NiMH wrapped in a lot of paper to keep the cells in place. As you can see, it is a lot dimmer than a dropin designed for the voltage. Actually I'm not that keen on long thin 2AA lights so I prefer the feel of the 504 with extension. But it isn't going to work well with AAs. The blue patch is daylight. This pic is at about 60cm 2 feet from the ceiling.
Thanks for your efforts, I agree that is not going to work at all.
I also have an L2R with the low voltage R2 drop-in, and just ordered an L2M with the same drop-in. I'm planning on running the L2M with a 18650 extension and power with 2xAA as well. When I saw the 504B I thought I could use the CR123 extension that will come with my L2M and have yet another cheap P60 2xAA light for the truck but oh well.
How does the L2R / R2 stack up to the 504B with its intended 18650 cell in terms of light output?
The L2R is my first good torch and so far I've been very happy with it for the $23 (itc_store sale) I paid.
Here you go.
L2r on the left - 504B on the right. By eye I can't tell which is the brighter. Time for the lightbox.
L2r 705 lux and dropping
504 955 and dropping. Neither appear to be much regulated.
Throw numbers
DX R2: 11050 lux at 1 metre
L2r: 8003
Just out of interest I'll try the Solarforce low voltage dropin on the 18650
Throw 10350 so it doesn't throw as well as the DX dropin
Lightbox 1190 but it is brighter on 4.2V
Looks like the L2R is pretty decent for someone wanting 2xAA power, I think I'll like the larger tube on the L2M better however and also have more battery
compatibility. Just need to figure out what size O-rings will fit AA cells and take up the extra room, thanks for the test.
Hi.
I'm new here and i like the forum very much.
I just ordered the Ultrafire WF-504B with 5-mode R2 drop-in on DX.
The review was the deciding factor to get the light. Now, the only thing i don't like about it is the badly designed driver.
What kind of regulator should i get to convert this beauty to a constant brightness with 2-3 modes. Don't mind the slightly reduced runtime tho.
I found a 2.7-4.2V buck/boost driver with modes on KD but it is soldout for ages.
Any reccomendation for a cheap solution? No 30$ regulators please, afterall this is a budget light forum :D.
I plan to use this light for trekking biking so i would love a 100% and around 50-60% brightness mode, a lowly one would be nice but not really required. The steady-ish light output is top priority.
Kind regards,
Budgeteer
Not the cheapest driver, but under 30 $. 
Regulation is exceptional, it's the driver of the L-Mini II.
Damn! I thought some1 would post that one. Trouble is im from EU and with shipping costs and toll hassles im not even considering to buy from them althrough i would love to since they carry spledid custom made chinese lights. Basicly they pimp the most popular chinese lights for not much of a premium. If i exceed 22Eur i have too much of a hassle. Prefer HongKong based solutions even if not very reliable.
Would love to get something in range 4-15usd so i can add the usual few $ of DIY parts (orings, switches etc.) and have them deliverd with no hassles and free in a few weeks god helping.
Found nothing really of use on KD (maybe but product descriprions are miserable). Absolutely nothing remotely trustable on DX the shop i often use. Generall slow but 8 orders so far and all ok.
Nothing else usable preferably from HK?
I really like the NANJG AK-47 driver. I used one with a XP-G R5 LED and it is nice. I bought a second one for my R2, but I haven't installed it yet. It has linear regulators and stays in regulation for a long time. Plus it can be hard wired to the number of modes you want.
http://budgetlightforum.cz.cc/node/310
The only advantage the 112A buck-boost driver has is that it works with AA batteries. But in a 504B that isn't needed.
Awesome! Just the info i needed!
The 405B uses a R2 emitter which is driven at somewhere near 3.6V and 1000mA for full brightness if i got it right. Then out of the blue why doesen't a lets say true 2400mAh 18650 cell provide around 2h runime roughly calculating in the expected power losses? In the ideal world it should run 2h and 20 min (not counting regualtor loss). I would be inclined that the reviewed grey trustfires 2400mAh would only hold about 1800mAh (probably wasn't evben born perfect and have seen some heavy use) to achieve 1h and 20min only.
So i basically order a set of needle nose tweezers (handy for DIY), the driver and try to do a good solder job. I guess the pcb dislike prolonged heat from a soldering iron or it is quite tolerant perhaps? I'm used to repair computer motherboards and i think if i did not cooked those the driver pcb should be fine? I was thinking to add solder to the driver and flashlight pill both separately then do a neat job by just adding enough solder to finish the job joining the driver to the pill. I presume it is done that way or please enlighten me. :)
If i do a good job by improving the pill contact with the body the flashlight will be adequately sinked to run full time 1h? Or it will be uncomfortably hot? (i have only experience with 1 AA & 2 AA flashlights)
One last thing. Where do i get the spring for that pcb? I guess i would need one since my 18650 are nipless. Should i order some backup 16mm clicky switches along to have spares and gently kill/gut one for the spring?
Thanks to all for your time and exceptional information value.
Kind regards,
Budgeteer
You can get the spring off the old board usually. The boards seem pretty tolerant of the heat. If you've soldered electronics before you won't have any trouble. I haven't had much luck replacing switches, they never seem to fit right. There are so many different switch designs out there and they all have their own way of fitting the pieces together in the tail.
Make sure you put some aluminum can shims in the head around the drop-in to get good heat transfer and the light should be fine. With an R2 it will just get warm, not hot.
Thank you. I owe you a beer. :)
I will try to use an aluminum or copper foil with a certain thickness an cut it to a suitable form so the pill can embrace it tightly with no air pockets. (im an expert custom pc heatsinker for ages.)
I just use good old aluminum foil that you put on food and it works great!
This is definitely the optimal way - at least if you have appropriate metal stock and can cut it neatly - me, I'm sticking to aluminium foil wrapped tightly with enough of it that I have to force the dropin into the head.
Do you know if it came burnt out or the heat caused it to burn out?