dougmc

Assuming 1200 mAh AAA cells with an average voltage of 1.3 volts (probably on the high side) -- three of them can put out 5 watts for 56 minutes.

Alkaline batteries have vent holes too. They're hidden, but they're there, just in case, for the same reason.

What's your concern about a metal tube? If something were to go wrong (unlikely, but possible), wouldn't that be the best place? The most likely problem (alkaline or li-ion) that's related to a metal tube is that the battery would swell or leak and you couldn't get it out of that metal tube -- so a ruined flashlight, maybe, but any mess is contained. Note that both 18650 and alkaline batteries are basically metal tubes with vent holes as well.

They do not get hot while charging unless you're abusing (ruining) them. They barely even get warm. As for discharging, that's your emitter that's putting out all that heat, not the battery. (Even the best LEDs nowadays are only like 14% efficient, which means 86% of the energy gets turned into heat.)

(The battery does put out a little heat, yes, but even the current if it's enough to drain the battery in one hour (a 1C rate) the battery temperature will only go up by a few degrees at most.

NiMH cells got hot during serious fast charging (charging in 15 minutes or less) but that doesn't happen with Li-ion/LiPo batteries charged at a 1C (full charge takes an hour) or lower rate -- at most they get a bit warm. Alkalines have a higher internal resistance and so they'll get warmer than the 18650 rechargeables at the same current.)

Neither are alkalines.

Yes, I already covered that. For a short trip, you can easily carry enough precharged batteries. For a long trip, I'd probably want a dynamo. But what about your Magicshine? (Probably with it's 4x18650 cells in it's battery pack, I might add.)

It may be the right thing to do with alkalines -- but I'd rather just go rechargeable and skip it entirely.

lopek77

18650 can explode in rare situations and it happend to many of us. There is a tread just about that. Something like that happend to one German cyclist. Because of the pressure of escaping gas from faulty? Overcharged? 18650 batteries , closed tube of little torch light exploded with a lot of damage to this guys kitchen and his both hands and arms. His skin was cut to his bones. There is a lot of pictured showing the damage.

My 3 AAA batteries are 1.5 v each , and this torch shines at full power for good couple hours, and after that for another 2-3 hours of good light safe enough for 15 mph ride. Still, I change batteries every 10 hours or so. When its cold, they don't last that long.

My magicshine battery pack is 2x 18650, but its in open design case, so if it blow for any reason ( moisture for example ) gas will easily escape without throwing pieces in my face or hands.
I would recommend buying 18650 from big, well known companies like Panasonic or Samsung, and only protected ones.

dougmc

Link to this thread?

It may have happened, but I doubt it's happened to *many*. And note that alkaline batteries can be easily turned into "hot steamers" too.

The $4 ones I've referred to are protected. As for who makes them, dunno -- my guess is that there's only a handful of factories and people just slap their brands on them.

davidad

I hope this stops this BS. https://batteryuniversity.com/

lopek77

I'm against giving everything on a silver plate, but I will do it one more time:
https://www.candlepowerforums.com/vb/...000mA-exploded

If in doubt , Google will always have an answer...

Cyclist0383

As the vast majority of us who use flashlight use single cell lights, I'll ask; where has it ever happened in a single cell light? I have yet to see any reports of a single cell light exploding. The thread you linked to is about a three cell light using poor quality batteries exploding after the cells were charged on a charger that is known to over charge cells. Leaving Li-ion batteries on the charger overnight is never a good idea.

That being said I always use quality cells such as AW or Redilast.

dougmc

Just for the record, I'm aware that lithium batteries have exploded. I've been flying R/C planes for longer than seriously riding bicycles and that's the hobby that has really had the brunt of it (and rightfully so, as we tend to really abuse our batteries.)

However, your "There is a tread just about that. Something like that happend to one German cyclist" made me think that the thread was on bikeforums, but I couldn't find it (because I made an incorrect assumption.) As for exploding/burning battery threads, there isn't just one -- there's dozens, perhaps hundreds. Check out rcgroups some time.

Though I've seen more than a few pictures of burned planes, cars and houses -- I've never seen one that really hurt anybody, so that's a new one.

If you're worried about buildup of pressure, drilling a hole or two in your flashlight would give it somewhere to escape. And yes, this can happen with non-lithium batteries too.

The danger is going to be less with single cell setups. And as the thread said -- "we don't often get reports of exploding 18650" -- but yes, it obviously can happen.

lopek77

You have to remember , that not everybody knows about charger that is known to over charge cells, or not to leave batteries in the charger overnight...
There is hundreds of lights and other electronics using 18650 online ( eBay for example ), where sellers offers battery packs and chargers with no name on It and without any manual...
If you think its awious to everybody what to do or not regarding to 18650 , you are just wrong.
And Yes, single battery can also blow...

Cyclist0383

Can you provide anything to show that a single 18650 battery has actually blown whist being used in a light? I've seen this claim time and again, but I've never seen any proof of it happening in the real world.

lopek77

First of all, the process of making 18650 is a "messy" one, and to make safe cell, there shouldn't be any metal contaminants - well known issue...
These are unstable, relatively short lasting batteries. I'm not against them, but it will take some time before they will be safe enough.
Again...Google it...I heard about single cell blowing up (releasing gases) first clue - cell phones...

no1mad 

Can we either table or move the topic of cell chemistry and potential explosive discharging from this thread and get back to the original topic of best lights for the buck under $50?

lopek77

I agree that this went little off topic, but at the same time, use and safety of many bicycle lights under $50 is important...many lights uses 18650, and it will be more of them, not less ...

chicagobent

So today my light arrived, yeah! It seems to be of decent quality for the price (the end cap threads on cleanly, the annodizing is good, and even the glow in the dark powder blue clicky doesn't bother me as much as I thought it would). There is however one very strange thing----on the flat panel on one side of the tube it says "Cree Q5" as expected, but on the other side it says "Sexy" as if that is the brand name or model name of the light. So, some of you have a Romisen, ITP or Fenix ligbt, but I have a Sexy light.

First problem, no instructions to tell me which way the battery goes into torch. I looked closely at one of the photos on the tmart site and it showed the battery negative terminal toward the tail, so that was how I installed it and the light works fine and didn't get blown out. The light is more than sufficiently bright for my purposes and will light a dark path well enough as well as cause me to be seen when riding on streets in Chicago. I leave it about 2/3 out of zoom (i.e. slightly more flood than focused). The ad stated three mode, but the decription indicated four mode-- fortunately for me because I didn't want too many modes, it has three modes, high, medium and high light level medium speed strobe (very usable), in that order. Correction, the middle mode is about one third as bright as the high mode, so really a low mode and the flash rate on the third mode is about 50% on and 50% off, so it is faster than medium, but still usable in Chicago.

The charger will not charge a 9 volt battery contrary to the photo in the ad, but given the price for the package, not really a big deal. It is small and will charge 18650, nimh or nicad, one battery at a time. Correction, it will charge a 9 volt battery-there was a sticker indicating correct polarity covering and hiding where the 9 volt battery plugs in to the charger.

The package included a brochure for the tmart site I referenced earlier where the light, battery, charger and bike mount package can be found for only $17 if you want it to ship from China instead of NY and can wait the extra week or two. So I'm guessing the seller in the ebay listing is simply tmart's US warehouse or distributor.

The bike mount cannot be located on my fork as it interferes with the spokes when placed low on the fork and it will not fit around the fork higher up where the fork is thicker bit the spokes are further away......so. I put the light on my stem because I don't like handlebar clutter. It holds the light very well and seems sturdy, but it is not easy the get the light on and off the mount, perhaps that will change as it gets broken in. I do like the 360 degree rotation feature.

Overall it is a great package for the price, a Cree q5 emitter aluminum torch which is fairly bright, one 18650 protected battery, a smart universal single battery charger, and a 360 degree bike mount---I paid $22.6, including free shipping on ebay and got the light in one week. The same light package can be had for $17 on the tmart site if you don't mind it taking a little longer to arrive.

I will update later after I ride more with it at night, including run time, recharge time, etc. I will ultimately get a spare 18650 cell to carry for longer rides, but that can wait.

Cyclist0383

We aren't talking about cell phones, we are talking about single cell 18650 flashlights in which the cells explode. You are making wild claims you can't back up. This does no one any good.

The fact remains that quality protected 18650 cells are quite safe when used properly, and there is no evidence at all of a single 18650 cell exploding in a flashlight.

borobike

Man, that made me crack up.
.
.
.

scoatw

Romisen RC-N3 CREE Q5 LED Flashlight still going strong into its fourth winter. Runtime is 4 hours on sanyo eneloop rechargeables.

due ruote 

Well that's just not fair. I've had mine a couple years and used it very little. Tried AA and rechargeable 123 batteries. It works great for about 20 mins then cuts out. Sometimes I can get it to come back on with a smack but usually it's out until I recharge. I thought maybe it was a rattling on the bike/shorting problem but last night I put a freshly charged battery in (I've charged this battery 10x at the most) and left the light on, laid on a table. It lasted about an hour, then shut off.

So now I'm thinking I should call it a loss and get a 18650 torch, which could at least use the same charger.

lopek77

Ok...I'm ready to give you my short review about Magicshine clone light I got and wrote about in previous posts.
My two cell battery pack (regular one is 4 cell) lasted around 2 hours. About 1 hour on low (very bright) and about 1 hour on high (crazy bright)
It wasn't fully charged, so I may get another 30-60 minutes of light when fully charged.
The mount (nut holding everything in place ), broke today after second use, when I was putting it on another bike. I fixed it using regular nut.
Its also incompatibile with fatter mountain bike handlebars, not impossible to use it , but hard to make it right.
There is a main switch on the light with led inside, and when power goes down it will blink red (it's not a good idea to drain complatelly this type of batteries)

It shines really well for quarter, half a mile? with great trow and flood, covering everything far, close and up (low hanging brenches)

Since my mount is not fully functional anymore, I bought replacement mount base for the original Magicshine light from Geomangear.com, and two rubber mounting rings (small and big) from Ebay seller.

I'm still very happy with tghe light and I highly recommend it, as a quite cheap and really good light.


UPDATE
People are NOT happy seeing me on the trail when dark... ;-)

New mount base installed, with some modifications to it to fit power cable. $6 and 5 minutes...DONE

xn7

awesome cree lights guys, crazy prices i'm shocked. i'll keep these in mind

lopek77

Few more words about magicshine clone light...
- for mountain biking buy flood lens ( about $6 on eBay )
- 2x18650 battery pack lasts around 2-3 hours on high
- try not to shine at people...they get aggressive... Last night someone said it looked like a freight train coming, it was on RTT trail BTW ;-)
- some battery packs are not waterproof...I found best placement for it - under the seat.
Again, awesome light! I will try to take some pics with better camera to show how well it works.


It looks little better on the pic...

danielgaz

My Planet Bike Blaze 1W is no longer enough. I can't see anything besides what's directly beneath me, and it's getting scary on the 6-mile commute home. I would be willing to spend $50-$75 bucks on a light that will actually give my dark commute (to and from) some illumination. Is the handlebar + Two Fish option the best, or is there a bike-specific one at that price range I should be considering?

Kingshead

OK, just checked the internet. If your light was designed to run on standard batteries it's light output will be diminished by 20% using rechargeables, period! A standard alkaline's rated 1.5volts is 25% greater than an eneloop's 1.2volts, is this acceptable to most here? If you are running rechargeables in your light, switching to alkalines will greatly increase your light's output. I think I'll stay with the trusted and true battery until someone gets their act together and manufactures a real replacement. Try running anything with a motor (portable CD player for instance) with a rechargeable and see what happens. Years ago my son was highly displeased when on his 4th Christmas his new battery operated train would only run without the cars attached because Daddy wanted to save money. After reading some of the posts here extolling the eneloop battery I was hoping this meant something had changed, but sadly I was mistaken.

I also read on hear that an 18650 was equal to 3AAA batteries, this is completely false. The 18650's rated output is 3.7volts, 3AAA's will put out 4.5volts, about 22% more. Again, the light will emit more lumens with the AAA's.

Found these on ebay for $8.99, free shipping. Cree 5watt, all aluminum housing, 270 lumens, 3AAA batteries required. Comes with a rear light as well so I ordered 2, I'll let you know how they work.

dougmc

You seem to have some misconceptions about rechargeable batteries.

NiMH and NiCd cells start at about 1.4 volts and go down from there. 1.2 volts is the "nominal" voltage given for them, but they start higher -- and really, once they hit 1.2 volts, most of their energy has already been used. As you said, alkalines start at 1.5 volts and go down from there. The "nominal" voltage is given differently for primary and rechargeable batteries. (Why, I do not know.)

But it's not that simple. Rechargeables tend to have lower internal resistances than alkalines, which works better for high drain devices. (Like bright lights on high settings.)

As for 18650 batteries, their nominal rating is 3.6 or 3.7 volts, but they start at 4.2 volts. Yes, three alkalines would start at 4.5 volts, but the *significantly* lower internal resistance of that 18650 over 3xAAAs will mean that if you're using the light described earlier on high mode the light will be *brighter* and stay brighter for longer (due to the larger capacity) than it would with your alkalines.

Also, you seem to be confused about the relationship between voltage and light emitted -- you seem to be assuming that it's linear, but it's often not. For example, with an incandescent light, the energy consumed is proportional to voltage *squared* assuming that the resistance stays the same (which it doesn't, just to complicate things.) And to further complicate things, the efficiency (amount of of visible light emitted per power used) typically goes up as the power goes up, as the filament gets hotter. In the case of an incandescent light, a small reduction in voltage usually leads to a larger reduction in light output.

As for LED lights, it depends. The better ones have regulators that keep the light output fairly constant over a range of voltages, and the cheaper ones are fairly linear with voltage as you suggested -- but things do vary.

In any event, people who use rechargeables often aren't after the maximum possible brightness. Instead, they're looking to save money and reduce waste. But if you keep your batteries charged, they'll likely be brighter than the alkaline batteries that you keep using until things get dim because you don't want to throw out batteries that are only 1/4th discharged.

Good bicycle lights (ones that put out a lot of light) use a lot of power. Alkalines could be used, but it becomes expensive. Rechargeables (or a dynamo) are what makes it cost effective to use a 400+ lumen light. If you're forced to use alkalines, you'll probably opt for a 50 lumen light instead to keep your costs down.

Um, the real replacements are here now. NiMH cells are largely drop-in replacements for alkalines (with a slightly lower voltage at first, which most lights handle just fine, as being designed to deal with alkalines and their always dropping voltages) and while Lipo and li-ion batteries generally aren't drop-in replacements, they tend to be superior when lights are designed to use them. Lead-acid and gel cel batteries are largely obsolete for the purposes of bike lights, but they still worked pretty well.

Hey -- 1995 called, it wants it's CD player back. Today, most music players come with rechargeable batteries. But even with that CD player, NiMH cells will work great in it, I don't know what your problem was. (And really, a dollar an hour for batteries adds up fast for listening to music!)

Motorized toys are exactly what NiMH cells work great in. Their lower internal resistance is important for high drain items like that, and the high drain also means that neither battery lasts long -- which gets expensive with alkalines.

Also note that today's NiMH cells are considerably better than the NiCd cells of "years ago" in most respects. NiCd cells had somewhat lower internal resistances and self-discharge rates than NiMH cells, but the new NiMH cells like the Eneloops have given NiMH cells those advantages and then some.

For a "blinky" tail light, I'd say go ahead and use alkaline batteries unless it's a really bright one. For example, a Planet Bike Supeflash lasts 100 hours on alkalines -- that's pretty good. But 3xAAAs wouldn't even run a 400 lumen headlight for a full hour (or if it did, it would be way below 400 lumens during most of the hour) -- you'll want to use rechargeables for that, or if you must use alkalines, use a much weaker light.

Edit: I've got what looks like that same headlight from DX. (Maybe it's the same, maybe not.) They claim it's 3 watts, but I think it's more like 1 watt and 50 lumens when comparing it to other lights. I haven't tried to measure the actual current draw, however, and don't have the equipment to measure light output (beyond comparing beam patterns with my eyes, of course.)

3xAAA alkalines (good ones) would contain at most about 4 watt*hours of energy total -- so if your light really did use 5 watts, it would last less than an hour. A single 18650 holds about 9-10 watt*hours of energy.

I don't really think they'd make a real 5 watt light that uses AAAs -- AAAs would have a hard time sustaining that level of current draw, though NiMH cells would do better than alkalines.

Kingshead

Apparently you didn't read my post or you would have read about my experience with rechargeables in a toy train, it was a disaster, and a waste of a lot of money. You are absolutely right that purely resistive loads will operate but at a diminished output with no long term degredation. The new LED lights use voltage regulation but continually running them with low voltage will shorten it's lifespan. I don't want to argue about this but as my life's work has been dedicated to electricity (Electronics Engineer, Master Electrician since 1987, College professor teaching Industrial Electricity, etc) I'll overlook your thinking I don't know what I'm talking about. I'm not going to get into the technical aspects, it's just not that important.

As I said, if the device was designed to use rechargeables (I-pods for example) then all bets are off. I only used the portable CD player to illustrate a point as it's motorized. I've most likely worn out more rechargeable handtools than you've ever seen so I'm no stranger to how they work. Their design takes into account the voltage the supplied batteries output, and the new Lithium Ions drop off rate is outstanding, but the older Ni Cads run longer and have a longer useful lifespan. Try putting a higher voltage rechargeable into your hand drill and see how much faster it runs. Numbers don't lie, do the math, 20% less voltage is still 20% less voltage no matter how you want to spin it.

lopek77

Really bad design and light output. You won't be happy with it, especially when comparing it with almost same price and with same cree q5 light torches on eBay...check my postings for a "good" torch ... Sorry....