LED flashlights

[mubs]

Thanks jtr, I'll read up on that link.

 

[Handruin]

FWIW, I wouldn't expect that flashlight to be anywhere near comparable to the PD35.

I like the KeepPower protected 18650 cells that are built around a Panasonic 3400mAh 18650 cell. There are cheaper protected 18650 cells built around the same Panasonic 3400mAh cells, but they have more losses in the protection circuit. I just picked up another 10 of these a few days ago from E2 Field Gear. They're $11.80 each after 20% coupon code. I also should point out that protected 3400mAh 18650 tend to be a little oversized in diameter and length and don't fit in all lights that claim 18650 support. HKJ has done great work reviewing and characterizing various Li-Ion batteries here. He also has individual reviews here.

On the charger, It's a bit less clear. There are lots of cheap Li-Ion battery chargers that barely charge a Li-Ion in an acceptable way to some that don't. I use a $100+ iCharger 206B that is an RC pack charger. I've made up some battery holders that hold multiple 18650 cells in series and charge them like they're a multi-cell RC pack. If you want a Li-Ion charger that works with individual cells I'd probably recommend one of these Xtar chargers HKJ reviewed: Xtar SP2, Xtar VP1, or Xtar WP2s depending on what you want to spend, how quickly you want to charge, and how many batteries you want to charge at once.

I ended up taking your recommendation on several of the above items. I got the DB POWER WF 501b Cree Xml T6 flashlight as a gift to get my into LED flashlights. It's fairly inexpensive so hopefully it'll perform worthy of the $12 it cost. I decided to take your recommendation and bought one of the 18650 KeepPower 3400 mAh batteries from E2 Field Gear. I couldn't get the 20% off like you but I did find a coupon for 12% using the BLF code. The battery came today and it fits fine in this flashlight. That was my main reason for only ordering one to make sure it fit before getting several. I also got the Xtar VP1 charger as a gift. At least now I have all the parts to continue with getting into flashlights with the 18650 sized batteries. Once the battery is charged I'll give the flashlight a try at night to see how well it works. If it does well I'll probably pick up a second or third to keep around in various locations along with some more batteries. Thanks for the help and suggestions.

As a general question, is it better to charge these 18650 batteries with the lower amp rates than the higher? The charger offers 0.25, 0.5, and 1.0amp charging rates. I'm currently using the 0.5 rate to charge the battery. I'm guessing the lower rate might help keep it from heating up too much thereby extending its life a little. It will of course take longer to charge at lower rates.

 

[Stereodude]

As a general question, is it better to charge these 18650 batteries with the lower amp rates than the higher? The charger offers 0.25, 0.5, and 1.0amp charging rates. I'm currently using the 0.5 rate to charge the battery. I'm guessing the lower rate might help keep it from heating up too much thereby extending its life a little. It will of course take longer to charge at lower rates.

On cylindrical 18650 cells you only want to stay below the max charge rating of the cell. On most that's .3C (C as in capacity not amps), however the 3400 Panasonic cells are rated to .5C (1.7A).

 

[Handruin]

On cylindrical 18650 cells you only want to stay below the max charge rating of the cell. On most that's .3C (C as in capacity not amps), however the 3400 Panasonic cells are rated to .5C (1.7A).

Thanks. Is there any benefit to charging at lower amp or does it not matter? Sounds like I'm still well within the range even at 1 amp.

 

[Stereodude]

Thanks. Is there any benefit to charging at lower amp or does it not matter? Sounds like I'm still well within the range even at 1 amp.

Not really. Depending on how your charger works you might get a tiny bit more energy into the cell at the lower rate, but that's in the noise relatively speaking.

 

[jtr1962]

Thanks. Is there any benefit to charging at lower amp or does it not matter? Sounds like I'm still well within the range even at 1 amp.

You might get more cycles out of the cell but practically speaking most of the time Li-ion cells die from age, not cycling. Most decent li-ion cells are good for at least 500 cycles and/or 5 to 7 years, whichever comes first. Unless you cycle your cells every few days, you won't come anywhere near 500 cycles in 5 to 7 years.

If durability and longevity are your ultimate concerns then you wouldn't be using standard li-ion anyway, but rather LiFePO4. Decent LiFePO4 cells, like the A123 cells, can last thousands of cycles. The jury is still out on calender life, but LiFePO4 may well last decades in service.

 

[Stereodude]

Yeah, and they have like 1/3rd the energy in them and don't work in a standard Li-Ion charger.

 

[jtr1962]

Yeah, and they have like 1/3rd the energy in them and don't work in a standard Li-Ion charger.

Actually the larger sizes (i.e. 26650) have about 2/3rds the energy of state-of-the art li-ion. I have 26650s which are 3300 mAh @ 3.2V. The best LiCo 26650s I've seen are around 4400 mAh @ 3.7V. Granted, they don't work many standard li-ion chargers but I am seeing more and more chargers with the option to charge LiFePO4. This is one of those things where either you need the advantages of LiFePO4 or you don't. If you do, you're willing to accept the lower capacity, plus the fact that not all li-ion chargers work with them. Besides the longevity, I like them because they're a safe chemistry. You can overcharge them, reverse charge them, even hammer nails in them without major incident.

 

[Stereodude]

Actually the larger sizes (i.e. 26650) have about 2/3rds the energy of state-of-the art li-ion.

That's because none of the Li-ion players are trying to push the envelope in anything but a 18650 cell. You can get a 3400mAh 18650, but can only get up to ~4400mAh 26650. If a LiCo 26650 had the same energy density as 18650's there would be 7000mAh 26650 cells. FWIW, Panasonic's roadmap shows them working on a 4000mAh 18650 so the discrepancy is apparently only going to get bigger.

 

[mubs]

Way too many flashlights do not use LiFePO4, specifically banning their use. It's also difficult to find good chargers for them.

Handy, please read the instructions for the charger before deciding the charging rate. At least for NiMH, chargers look for the termination signal to stop charging; this is typically a negative delta V signal (a small voltage drop at the conclusion of the charge). This signal is masked if charging rate is less than 0.33C for a NiMH. Don't know the values for Li-Ion. I use a Maha C9000 charger/analyzer for my Eneloop AA and AAA cells.

I ordered my bunch of flashlights.

In October I had procured a black Fenix E05 and a Fenix HL21 headlamp locally at a 40% higher price. Ordered the rest from the US a couple of days ago:

- Zebralight SC52w Neutral White from E2 Field Gear. Mike was kind enough to test and ship me a version that does not suffer from the green tint. This is my "pocket" light.

- Sunwayman D40A & Nitecore NFD40 White diffuser for it from GoingGear. This will be my "power" light.

From Fenix-Store (they haven't shipped yet; "Manual Verification Required" - probably related to my non-US credit card):

- Fenix LD12 XP-G2 (R5): for the bedside

All the above use AA cells; the lights below use AAA cells.

- Fenix LD01 R4: alternate keychain light

- Fenix E01: low power light

- Fenix E05 Blue: keychain lightfor the kid

- Fenix E05 Purple: keychain light for the wife

I've decided to stick to AA & AAA cells for now. Didn't need the headaches of a new form factor / charger / chemistry. Maybe later.

I also have a marked preference for lights that have a button on the side to change modes, in contrast to the head-twist types. With the smaller lights like the E01, E05 and the LD01, their small size precludes them from having a switch on the side, and I have to settle for the head-twist. It's not such a big deal because except for the LD01, the rest are single mode and head-twist is the on-off mechanism.

I think this qualifies me to be a noob flashaholic.

 

[Stereodude]

I think this qualifies me to be a noob flashaholic.

Yes, but you're jumping in with both feet.

 

[Handruin]

You might get more cycles out of the cell but practically speaking most of the time Li-ion cells die from age, not cycling. Most decent li-ion cells are good for at least 500 cycles and/or 5 to 7 years, whichever comes first. Unless you cycle your cells every few days, you won't come anywhere near 500 cycles in 5 to 7 years.

If durability and longevity are your ultimate concerns then you wouldn't be using standard li-ion anyway, but rather LiFePO4. Decent LiFePO4 cells, like the A123 cells, can last thousands of cycles. The jury is still out on calender life, but LiFePO4 may well last decades in service.

If the cell lives 5 to 7 years I'm cool with that. Given the amount I'll use the flashlight it will likely die of old age before cycle counts. Those LiFePO4 sound neat but I don't need that kind of specialty battery for my usage.

 

[jtr1962]

If the cell lives 5 to 7 years I'm cool with that. Given the amount I'll use the flashlight it will likely die of old age before cycle counts. Those LiFePO4 sound neat but I don't need that kind of specialty battery for my usage.

Flashlights for the most part really aren't a great use of LiFePO4. The exceptions might be lights which use either AAs or 123s. Provided the light is compatible with higher voltage, a LiFePO4 AA (14500 size) usually offers more runtime even if it has less energy than AA cell. The reason is most drivers in AA flashlights aren't very efficient when boosting the ~1.2V from a AA cell to the 3V or so needed by the LED. Half the energy in the cell might be wasted as heat in the driver. On the other hand, LiFePO4 run at 3.2V, very close or at the voltage needed by the LED. In a properly designed driver, there should be minimal losses. Often LiFePO4 will work even in a AA light not designed for it because most boost circuits go into direct drive when the battery voltage exceeds the forward voltage of the LED. LiFePO4 often exceeds the LED's forward voltage, but not enough to burn out the LED, as can happen with regular 3.7 li-ion 14500s. As for 123s, this is a size where the regular li-ion alternatives really aren't that great IMO. Also, many flashlights don't work with li-ion R123s because the voltage is too high (3.7V instead of 3 to 3.2V). LiFePO4 provides a good match to the voltage of non-rechargeable 123s.

Other than those uses, the best use of LiFePO4 is in devices where the advantages outweigh the lower capacity. They're seeing heavy use in solar garden lights where NiCad and NiMH just don't last. I also think bike lights are another great use for them. If you ride a lot at night, you might be cycling the cells 100 to 200 times a year. You can easily wear out regular li-ion doing that. Same thing with NiMH with the exception of quality cells like Eneloops. Also, a well designed bike light can easily last for more than 5 to 7 years in service. I'd rather use cells which have the potential to last as long as the light, even if it means lower energy density. The safety is a bonus.

 

[jtr1962]

Way too many flashlights do not use LiFePO4, specifically banning their use. It's also difficult to find good chargers for them.

LiFePO4 123s will work in any flashlight which uses primary 123s. The voltages are more or less the same. You lose about half the capacity compared to primary 123s, but you save a ton of money.

Handy, please read the instructions for the charger before deciding the charging rate. At least for NiMH, chargers look for the termination signal to stop charging; this is typically a negative delta V signal (a small voltage drop at the conclusion of the charge). This signal is masked if charging rate is less than 0.33C for a NiMH. Don't know the values for Li-Ion. I use a Maha C9000 charger/analyzer for my Eneloop AA and AAA cells.

Li-ion use a completely different charge algorithm-namely constant current/constant voltage. You charge the cell at a constant current until the cell voltage reaches 4.2V (or 3.65V in the case of LiFePO4). After that you keep the voltage constant and monitor the current. The current will drop as the cell charges. When the current falls to perhaps C/25 you terminate the charge. The actual number often varies depending upon the cell manufacturer. IIRC A123 recommends terminating charge at C/100 for their LiFePO4 cells.

 

[jtr1962]

That's because none of the Li-ion players are trying to push the envelope in anything but a 18650 cell. You can get a 3400mAh 18650, but can only get up to ~4400mAh 26650. If a LiCo 26650 had the same energy density as 18650's there would be 7000mAh 26650 cells. FWIW, Panasonic's roadmap shows them working on a 4000mAh 18650 so the discrepancy is apparently only going to get bigger.

That's because 18650s are commonly used in laptops where both size and energy density matter. 26650s and larger cells are often used in applications where weight is the deciding factor (i.e. electric vehicles). A higher energy density 26650 will weigh proportionately more and therefore not provide any significant advantage because most battery packs in this use are constrained by weight, not volume. Also, higher density comes at the expense of cell life as we've seen with NiMH. When manufacturers tried to push the envelope with 2700+ mAh AAs, the end result was very short cycle life and very fragile cells. Finally, there's the issue of the ratio of surface area to cell volume. A 26650 cell has only 44% more surface area than an 18650 cell but 109% more volume. If you try to push the capacity too far, the cell won't be able to dissipate heat during rapid charging or discharging. This is why li-ion 26650s are probably going to be limited to less than 5000 mAh regardless of chemistry. Incidentally, LiFePO4 is theoretically capable of reaching that capacity also in a 26650. So for smaller cells, yes, LiFePO4 is at a marked disadvantage but this diminishes rapidly as cell size increases. And as I said, other than the uses I mentioned 2 posts back (i.e. 123s and some AA lights), LiFePO4 really isn't a great type of cell for flashlights unless you have a light which takes 26650s.

 

[mubs]

Thanks for the info, jtr, very useful to know. I Really appreciate you sharing your knowledge here.

 

[Handruin]

Thanks jtr on the info.

How long do 18650 cells last when sitting around in a flashlight unused? Normally I might call this static discharge but I don't know if that's the right term for these cells or even if they're affected much if at all by this. Basically if I want to leave one of these lights and one of the KeepPower 3400 mAh batteries in my car, how long do you think it'll keep a usable charge? I'm sure weather/temperature play a role in this, so for the sake of this question, let's assume out door winter temps in the car (0F -> 30F | -17.7C -> -1.1C).

 

[Handruin]

How good of quality are Nitecore lights? I saw a few of you mention their name earlier in this thread and was curious if anyone has any experience with their flashlight products? I like the nitecore SRT6 with the rotating adjustable output. I'm still drawn to the Fenix PD35 and in that lumen output range but the nitecore SRT6 seems to be a close contender for price and output performance, albeit it looks slightly larger. They're both similarly priced and both are relatively close in output (PD35 @ 850 lumens | SRT6 @ 930 lumens). One feature making me lean toward the SRT6 is the infinitely variable brightness adjustment ring. The SRT6 also has a stainless steal protection ring on the front to help protect it if dropped.

 

[jtr1962]

Thanks jtr on the info.

How long do 18650 cells last when sitting around in a flashlight unused? Normally I might call this static discharge but I don't know if that's the right term for these cells or even if they're affected much if at all by this. Basically if I want to leave one of these lights and one of the KeepPower 3400 mAh batteries in my car, how long do you think it'll keep a usable charge? I'm sure weather/temperature play a role in this, so for the sake of this question, let's assume out door winter temps in the car (0F -> 30F | -17.7C -> -1.1C).

The correct term is self-discharge. In general, li-ion cells don't self-discharge much, perhaps about 5% per month. Note that self-discharge is exponential. That means if a cell loses 5% a month, it will have 95% charge after a month, (0.95)² after two months, and (0.95)^12 = 54% after a year. Some of the better li-ion cells lose less than 3% per month, you'll have (0.97)^12, or 69%, after one year. Those are good ball park numbers for li-ion. In general, sitting for six months shouldn't be a problem. A year or more might be, depending upon the cell. The colder the weather the less the self-discharge. If you put a fully-charged light in your car before the cold weather starts, I'd say you'll have no issues with the battery retaining much of the charge all through the winter. In the part of the country we both live in, for 8 months out of 12 the outdoor temperatures are generally below room temperature. If anything, that means you'll do better than the numbers I gave. In short, so long as you check your light a few times a year, you should be OK. It's good practice to do so anyway, regardless of self-discharge, just to make sure everything is working. Switches sometimes become oxidized, for example.

For really mission critical uses I would use a light which takes AAs. The latest generation of Eneloops will hold 90% of their charge after one year. The only downside of Eneloops is they may not work optimally if temps are under about -20°C. This is relatively rare where we live.

 

[mubs]

Handy, be wary of claimed turbo output. Very few manufacturers will tell you run time at max output is limited - 3 mins, 5 mins, 10 mins, etc. Either the circuitry will step down the output, or you will because it'll get too hot to hold. Fenix lists this info in the manual for some of their models, not all. Nitecore lists this for some, not all models on the product page on their website. The only ones I've seen that are consistent with full disclosure are Sunwayman and Eagletac.

 

[Stereodude]

How good of quality are Nitecore lights? I saw a few of you mention their name earlier in this thread and was curious if anyone has any experience with their flashlight products?

I have one, the EA8. It's seems fine. The build quality is solid, the finish is nice. It's very throwy, so I don't use it much.

 

[mubs]

Yes, but you're jumping in with both feet.

Guess that's a polite way of saying I'm in over my head :rofl:, and you'd be right. The stuff's going to hit the fan when the wife finds out how much I've spent on "flashlights".

 

[Stereodude]

The stuff's going to hit the fan when the wife finds out how much I've spent on "flashlights".

Well, you don't have to tell her. :bomb:

 

[time]

Need a spectacular light for someone as a thank-you (they're not easily impressed). Good throw (i.e. high lux in the hotspot) would be good.

I saw Stereodude's triple-18650 suggestions, but frankly I'd prefer a single 18650 unless there's a huge advantage. Any ideas?

 

[Stereodude]

Budget, how long does it need to run, multiple levels?

Are you looking for a "Wow! That's bright!" impress your friends light or something actually useful?

 

[time]

Preferably under $100, 5 minutes will do, preferably more than one level, and "Wow! That's bright!" rather than useful. It's for someone who just likes to collect bright flashlights.

 

[CougTek]

Preferably under $100, 5 minutes will do, preferably more than one level, and "Wow! That's bright!" rather than useful. It's for someone who just likes to collect bright flashlights.

So basicly, you want a flashlight for someone who isn't a lightbulb?

 

[Stereodude]

Preferably under $100, 5 minutes will do, preferably more than one level, and "Wow! That's bright!" rather than useful. It's for someone who just likes to collect bright flashlights.

Not sure I really have a good suggestion for you. The really bright lights all use multiple batteries. Something like a Skyray King (don't blindly buy one, there are way too many revisions).

 

[mubs]

I saw Stereodude's triple-18650 suggestions, but frankly I'd prefer a single 18650 unless there's a huge advantage. Any ideas?

I presume this person already has and uses 18650s?

If not it's a whole can of worms learning about protected cells, getting the appropriate charger, etc. It might be better to go with AA based lights.

 

[CougTek]

You could just buy a stick magnesium with a torch blower. It would be very bright, but it wouldn't last long.

 

[time]

Indeed.

OK, I've been doing some research and have come up with these so far:

Heavily-modified Small Sun aspheric: 100,000cd

Olight M3X: it's 2 x 18650 and doesn't have a low mode, but does manage 90,000cd and seems to be available for around US$100?

Sunwayman D40A: 30,000cd, takes 4 x AA and even in Oz I can get it for about US$70. Surprise factor because it's relatively small.

There's also the 6 and 8 AA lights, but I don't particularly want to have to get an 8-way charger to go with it. And they're not really competitive with the Olight M3X anyway.

I lusted after a couple of Eagletac lights, particularly the GX25L2 with turbo head:80,000cd, but the total price appears to be astronomical.

 

[time]

.

 

[Stereodude]

No Deft-X or Firefoxes IV on your list?

 

[time]

Nearly $600 is a bit pricey for me ...

 

[Handruin]

Aside from the wow factor of having such a powerful and bright flashlight, what are some practical uses for something so large and heavy? Are you spotting rhino's from a helicopter at 400 feet?

 

[jtr1962]

Aside from the wow factor of having such a powerful and bright flashlight, what are some practical uses for something so large and heavy? Are you spotting rhino's from a helicopter at 400 feet?

Blinding potential attackers. If you shine a 100,000 cd flashlight in someone's eyes, especially at night when their eyes are dark adjusted, they won't be able to see a thing for at least 20-30 seconds. That gives you time to either escape, or if the light is heavy enough, use it to beat the crap out of the attacker. Some lights have crenelated bezels for exactly that purpose.

 

[Stereodude]

Aside from the wow factor of having such a powerful and bright flashlight, what are some practical uses for something so large and heavy? Are you spotting rhino's from a helicopter at 400 feet?

Which light(s) are you referring to as "so large and heavy"?

 

[Handruin]

Which light(s) are you referring to as "so large and heavy"?

The Eagletac MX25L2 time mentioned above looks to be large and heavy to carry around.

 

[time]

Sorry, the link I used refers to a group of 3 Eagletac lights; the GX25L2 I wanted is the relatively small one and the MX25L2 is the whopper. I think if I could get a GX25L2 with turbo head for a reasonable price, it might be worth keeping for myself.

 

[Stereodude]

The Eagletac MX25L2 time mentioned above looks to be large and heavy to carry around.

I guess it all depends on why and how you're carrying it. Certainly it's not an EDC or something you'd put in your pocket, however it's not any larger than a 2D Maglite and I don't think that's an unreasonable form factor.