Since I have never used rechargeable batteries...

I ordered a flashlight that can use either 3 x AA batteries, or 1 x 26650 rechargeable battery. I intend to use only the AA's. But I wonder if using 26650 would make it much brighter than using AA's? (and probably lasting longer)

I suggest using eneloops AA or AAA since you don't know a lot about rechargeable.

The 26650 cell is a very powerful lion battery and very dangerous cell if you don't know what you're doing. Read here if you'd like to know more.

https://www.candlepowerforums.com/vb/...000mA-exploded


That being said there are plenty of 3 x AA, 4 x AA, 6 x AA and so on flashlights that can be just as powerful as a single lion 18650 or 26650 cell. Which unit did you buy?

This is the main reason why I prefer not to use rechargeables. The one I ordered was this one.

P.S. What's with Eneloops? How about Energizer or Duracell AA's?

Nothing wrong with rechargeable in general, but you gotta be careful with battery chemistry, lithium or Lions are among the most powerful ones and the ones you gotta be real careful with.

Eneloops are among the most trusted brand of NIHM rechargeable batteries, nothing wrong with Energizer or duracells NIHM's though. The most important part is that you get a smart charger to go with your rechargeable batteries. Alkaline cells are not that good on powerful flashlights.

I use this one since it only cost me $12, but it's an australian version and comes with an australian prong. It does include an adapter for use with american style wall outlets.

https://www.amazon.com/Duracell-Charg..._sim_sbs_hpc_2

this is the more expensive american version that comes with the right prong for american outlets and doesn't require an adapter.

https://www.amazon.com/Duracell-Charg...cr_dp_asin_lnk

The charger I use is pretty nice since it lets you charge other devices (iphone, tablets, etc.) using AA/AAA batteries through a USB port.

BTW check out "Nlee the engineer" reviews in amazon if you need to find quality batteries or chargers, he usually has very informative reviews

You can also buy chargers that display voltages and can recondition AA/AAA batteries. Maha and La Crosse are the two most popular brands for that.

here's a review for your light and some beam shots on both 3x AA and 26650 batteries. scroll down for the beam shots
https://budgetlightforum.com/node/8803

HI 45, thank you so much for the info and the link about the light, very helpful! Re NIHM, is it something in between alkaline and Lithium, as far as the power and danger are concerned?

Yeah NIMH's are among the safest if you use a good charger and the most forgiving if you do mess up. I just place mine in the charger and forget about them without worry. If you use a fast charger or a dumb charger, the worst that can happen is the cell heating up and melting the plastic in the charger (this happened once when I used a fast charger ) . If the charger is defective that could also happen. I remember lacrosse had a fiasco with a faulty charger that would overheat rechargeable cells a while back, but they fixed that problem.

18650 Lion cells are used in laptop battery packs and they've also had issues with batteries overheating and causing fires, same with cars that use 18650 cells (tesla car) or phones and every other device that uses a lithium battery. So really the danger is everywhere, even if you aren't aware of it. The important part if you do use Lion cells is that you are aware of the dangers and check the voltages after they've been charged, also never over discharge them. Either of these things will damage the cell, as will dropping them, and the next time you try to charge them they could burn up.

NIMH's are the perfect batteries to get into rechargeables and if you do ever want to use more powerful Lion cells, using single cell flashlights are the best way to get started.

No problem on the help since it's one of my hobbies and BTW don't buy batteries from DealXtreme or any disreputable seller if you want to avoid problems.

vol, that light would really shine with a 26650 cell. On the danger. The danger is less than walking across the street! What I saying is, in everything that is done, at sometime or another something will fail and cause harm. How often is the key. The accidents with rechargeables way, way, way down the list.

I have a couple 3 aaa/26650 lights too, but I have yet to use the 3 aaa function. .. Maybe in a punch I might use them, but that is like driving a Corvette, that has 500 hp but only use 150 hp, or half the cylinders..

I just received my order of this UltraFire flashlight after about 3 weeks. Haven't used it yet, but looks good (though not sure how to verify the lumen number). Another item on DX, the Aurora, seems to be almost identical to the UltraFire one. The only difference I found is the runtime given: UltraFire is said to be 2-3 hours, Aurora is 90 minutes. I wonder if they are really different? Is anyone here familiar with them?

The problem with using alkalines in high power flashlights is that they are really not a good chemistry for delivering high levels of current. The capacity is badly derated when you start to draw a lot of current. If you draw a tenth of an amp from a 2000 mAh cell, you'll probably be able to do it for the 2000/100 = 20 hours you expect. But if you draw a full amp, you'll probably only get it for 45 minutes or so, less than half of what you'd expect, because the rest will be wasted by heating up the battery.

NiMH and LiIon chemistries are much more capable of delivering these levels of current without significant derating.

Due to my interest in not throwing something away that still has use, I got one of these:

https://www.amazon.com/Viatek-RE02G-G.../dp/B002MUAG1Y

This charger is capable of charging NiCad, NiMh, and alkaline batteries, and can handle AAA-D cells, as well as a 9 v(total of 5 batteries, if you don't have a C or D in either of the center charging channels). It is a smart charger that will charge until they are full and just keep them fresh after, and it will detect bad batteries as well(at least this revision does not use a piezo buzzer, which drove me nuts in the last rev). It may not bring alkalines back up to full force like a NiCad or Nimh, but it works.

So it seems LiIon > NiMH > Alkaline? Which of the two ">"s is of higher degree (>>)? (hope you understand my question )

Vol, as with all things it depends on the application as to which battery technology is best suited. Of the three battery technologies so far mentioned (by no means the only ones)

Alkaline = Very good choice for applications where a small amount of power needs to be drawn from the battery over a long period of time. Think smoke detector batteries that only get changed once a year and similar applications as what they are the very best suited for. Most are not rechargeable although rechargable alkaline battery technology does exist but is significantly handicapped by a limited number recharge cycles (usually only about 50 max.).

NiMH = A good reasonably safe rechargeable battery technology. Currently the most popular rechargeable battery technology for direct replacement of primary consumer cells for almost any application (or in other-words you can swap in a NiMH cell of equal size for all the popular battery sizes (AAA, AA, C, D, & 9V and the device will almost always work no problem). These cells are much better at delivering a larger amount of power over a shorter period of time and will perform better then Alkaline cells doing so but unlike alkaline cells won't hold their charge well enough to be used in applications that require them to still be working many months from when they were last charged providing a very low amount of power over an extended period of time (your smoke detector will start doing its low battery beep thing in just a month or two if you put a NiMH battery in it instead of an Alkaline). They are an excellent choice for powering a bicycle light that is going to be used on a regular basis and will work better for this application then Alkaline cells.

LiIon = in most chemistry combinations (there are more then one in this category) pack considerably more energy in the same amount of space then either Alkaline or NiMH cells. In the non-rechargeable chemistry variants they can provide a small amount of current over a long period just as well or better then an alkaline battery (they make non-rechargeable LiIon 9V batteries for smoke detectors that you can go twice as long without changing the battery compared to alkaline) and in both the non-rechargeable and rechargeable variants they can also provide a larger amount of power over a shorter period of time. The down side of this technology is that these batteries are subject to overheating and potentially catching on fire if charged incorrectly or too quickly and/or under continuous heavy current drain. This is especially the case if they have physical damage due to being dropped on a hard surface or such (dent = fire).




Long story short ~ for your application using the light in question as your bike headlight some better quality NiMH rechargeable batteries and a smart charger will do you just fine. The worst that can potentially happen is that you can potentially get them hot enough to melt them and even that is a rarity. So far in all my years of messing around with NiMH batteries especially the industrial sub-C size I used to buy in bulk for building my own battery packs I've only had that happen a couple of times and all it did was make a mess. I do and have used the LiIon technology batteries as well but lets put it this way - I won't leave them unattended in the charger something I do all the time without the slightest though with NiMH batteries.

The ">" between LiIon and NiMH is the one of slightly higher degree if one assumes conventional rechargeable LiIon technology.

IMO it's about like
LiIon >> NiMH >>>>>>>>>>>>>>>>>>>>>>>> Alkaline

Now that we have Eneloop and similar batteries, the places where alkaline is the best choice are mostly limited to very low drain devices like remote controls and smoke detectors. This is both for practical reasons - in a high drain device like digital cameras and flashlights, alkalines will derate and not actually last very long, and also for purely environmental reasons - we put thousands of tons of the nasty things into landfills annually and anything I can do to slow that down is a plus.

I use lithium batteries. They don't like to be dropped or overcharged. Proper caution is necessary. https://batteryuniversity.com/

Thank you so much to all, especially to turbo1889. It seems the rechargeable batteries have dangers during not only the charging but also discharging (over-discharging) process, either explosion or damage to the battery. If I don't frequently ride at night, the rechargeable batteries will be left alone for weeks or months. Will that be dangerous, too?

P.S. is 26650 more powerful than 18650? because it's a larger number? (obviously this is a dumb newbie asking )

The danger with rechargeable is mainly with the LiIon battery technology (although the old NiCd could get interesting as well) and not so much with the NiMH batteries which are much more stable and much safer. I wouldn't use the term "explode" in reference to LiIon gone bad but rather "catch on fire". I suppose explosion is technically possible but catching on fire is what usually happens when things go bad with LiIon cells. The over-discharge problem is mainly only an issue when trying to pull way too much power out of the cell all at once or with a badly damaged cell. For example I have a flashlight that uses a single 123A LiIon cell with three brightness settings and two flasher settings (typical 5 mode setup) where the high setting on that little itty bitty flashlight is rated to put out 1,200LM of light which pulls an incredible amount of juice all at once out of that one little battery and in the instructions it specifically says not to use the high setting on that flashlight for any longer then 5 minutes continuously and in only a couple minutes on high it gets so hot that it becomes uncomfortable to hold in your hand. Although I've never tried it there is little doubt in my mind that if I just left that flashlight on high with a freshly charged non-protected high density rechargeable 123A cell in it it would probably start on fire within 15 minutes. The newer model of that same flashlight by the same brand name is now only rated for 800LM of light output on the high setting so that tells me they probably had a few of the ones like I have burn themselves up because people left them on the high setting too long and they had to back them off a few notches for safety reasons with the new model. An 18650 cell is twice the battery or more then an 123A cell so half the strain or less would be put on it running the same light head (just with a longer body for the longer battery cell) and thus wouldn't present near the potential problem although 1,200LM on a single 18650 cell is still pushing the cell a little more then you probably should especially with a non-protected cell.

I should explain that as well. As technology has improved some of the more popular cell sizes on the market (18650, 123A, and even a few 18500) now come in a "protected" version which is more expensive but the cell has a built in micro-chip embedded in one end that limits both how quickly and how far it can be charged or discharged which significantly reduces the potential dangers. I still won't leave them in the charger when I'm not at home but I am more comfortable with them then the unprotected LiIon cells. Another possibility is LiFePO4 cells which is a stable safe lithium chemistry that is substantially more stable then all previous LiIon chemistry batteries and won't burn themselves up unless they have sustained substantial physical damage and even then they are as safe or safer then NiMH cells. The main problem with them is that since that technology is so new that it really hasn't made it into the smaller sized cylinder shaped cells that are commonly used to power flashlights and similar LiIon battery powered consumer electronics. I've seen a few 123A cells out there and some 18650 cells but you really have to search for them and they need a different charger then the other LiIon cells. In addition they put out 3.2V rather then the 3.7V that the other rechargeable LiIon batteries put out so there is some questions about whether stuff made to run off of 3.7V cells will still work off the lower 3.2V voltage.

I've got an electric assist bike that uses a LiFePO4 battery pack that is built from big brick shaped cells with screw terminals on the top similar to the old 6V lantern batteries and they work like a champ for that application and I've had no problems or worries at all leaving the charger on that bike in the shop while I'm away from the house. The batteries hardly even get warm to the touch while charging. I bought a few 123A cells and a charger in that chemistry that I was able to find and they do work for a flashlight I have that can either be run off of a single 18650 cell or two 123A cells but they didn't work to run that mini torch light that can put out 1,200LM on the high setting and I think that might be because that little thing is such a little power house that pulls so much out of such a small cell (even the dimmest setting on that thing is rated to put out 450LM). And I couldn't get them to run a 3@AAA flashlight with a holder I made to power those flashlights off of a 123A cell where as a 3.7V cell does work for that application but I think that is partially due to that light being set up to run off of 4.5V (3 x 1.5V alkaline) and while dropping down to 3.7V works 3.2V is too much of a drop.

So long story short at this point I can't fully recommend the LiFePO4 cell for running flashlights as bike lights because I still haven't figured out what all lights they will work with and which they won't (actually posted another thread in this forum section asking if anyone else has more info on what flashlights work on the lower 3.2V and which ones don't). Especially in your case since you are dealing with a flashlight that is designed to run off of either 4.5V (3 x 1.5V alkaline) or 3.7V conventional rechargeable LiIon so you would probably run into the same problem with a your 3@AA flashlight trying to use a LiFePO4 cell as I did with my 3@AAA flashlight and the 123A LiFePO4 cells with my home-made adapter.

As I said before from my point of view with you being a Newbie and you mainly seeming to be worried about safety I'm suggesting you go with some good quality NiMH rechargeable AA size batteries. As to what you are asking about leaving them unattended for a while between rides and still having them be good. There is currently two different categories of NiMH cells out there right now ~ Conventional NiMH and "Low Self Discharge" NiMH cells. The "Low Self Discharge" cells are the new technology and while the internal chemistry of the battery is the same they use a different type of separator compound inside from the old cells which makes them hold their charge for longer periods. Some of the better ones being advertised to only loose less then 20% of their charge over 6-months of storage time before use. The "Enveloop" batteries are of the low self discharge type of NiMH as well as several other brands although the only other brand I've found personally that works as good as the Enveloop is the Tetra brand high intensity NiMH cells.

Costco is among the best place to get a decent price on Enveloop NiMH batteries. Which are among the best low self discharge NiMH batteries. Three of their AAA size work no problem for me with all my 3@AAA size LED flashlights so I see no reason at all why three of their AA size wouldn't work great for your 3@AA flashlight.

As to the number designation of LiIon cells. The first two number are the approximate diameter of the cell in millimeters. The last three numbers are the approximate length of the cell in tenths of a millimeter. Thus an 18650 cell is approximately 18mm in diameter and approximately 65.0mm in length. The 26650 cell is just a larger diameter version of an 18650 cell and larger diameter means it stores more energy and can run longer before running out of juice. Just like a C size alkaline is the same length but larger diameter then an AA alkaline. The 123A cell is an "odd man out" in the sizing scheme and is basically the same approximate diameter as a 17650 or 18650 but is approximately half the length.

turbo1889, thanks a bunch for the very informative reply and sharing your own experience! I think I'll follow your and others' suggestion to buy the Eneloop NiMH rechargeables. Now I have another question, about the charger: most of the inexpensive chargers I see are for 2 AA batteries. The flashlight I have uses 3 AA (am contemplating another flashlight using 3 AAA's). My concern is that the 3 batteries should be charged at the same time for the same duration to prevent damage or early death of the batteries. Is this concern reasonable? Should I look for a charger for 4 AA's?

For the very best in a battery charger for NiMH batteries you are looking for two specific things:

~ First of all you want a smart charger that detects when the cell is charged and isn't just a simple "dumb" charger that just has a built in timing circuit that charges the cell for a set amount of time and then shuts off. Be careful with cheap chargers on that point because some will try their best to pretend to be true smart chargers with lights that change color when the battery is charged and such but on the inside are just regular dumb charger. What you are looking for is a charger that uses "delta V" detection to detect when the battery is fully charged.

~ Secondly it is best if the charger has individually regulated charging slots. There are many chargers out there including many of the smart chargers including the charger made by Enloop that charge the batteries in pairs and are not capable of charging just a single cell or an odd number of cells (such as three cells) but must charge in pairs. This will often lead to slight imbalances developing with one of the two cells in the pair not getting fully charged.

Here are some links to some chargers I know of that are both true smart chargers and that charge the cells individually:

https://www.amazon.com/La-Crosse-Tech.../dp/B0031ERMO4
https://www.amazon.com/La-Crosse-Tech.../dp/B000RSOV50
https://www.amazon.com/La-Crosse-Tech.../dp/B004J6DLD4
https://www.amazon.com/Powerex-MH-C90.../dp/B000NLUSLM
https://www.batteryspace.com/ch-v3150...irectplug.aspx
https://www.batteryspace.com/CH-V9228...-USB-plug.aspx



I personally own a La-Crosse Tech. BC-500, La-Crosse Tech. BC-1000, a PowerEx MH-C9000, and several CH-V3150 chargers. The La-Crosse Tech. BC-500 and the CH-v3150 chargers are the ones I use most of the time and I only end up using the BC-1000 or MH-C9000 units as "reform school" for straightening out "problem child" cells and getting them to behave themselves again.

The CH-v3150 is a cheap charger that is a true "Delta V" smart charger with individually controlled charge slots and it just does its job and does it well without any problems. The BC-500 is a nicer charger with a nice display and some additional functions that can come in handy (think reform school light version capabilities if needed). Either would do just fine for a beginner. I should note that there are other chargers out there that are basically the same as the CH-v3150 some even looking like they came out of the same mold on the same factory line just with different colored plastic and a different logo on them. That is design is basically the bottom rung of the good chargers that have both true "Delta V" intelligent charging and individual slots just without any fancy options or display screens.

Also ~ your going to want to get yourself at least 6-cells so that you can have three cells in your light and three fresh cells to swap out when needed. You don't want to buy just one 4 pack of AA's and then have to wait for the three in the light to get charged back up when they run down before you can ride again or end up having to use disposable cells in a pinch.

Before you know it you will just be buying more NiMH rechargeables every time you need AA or AAA batteries for something once you figure out that with just four or five recharges they pay for themselves and it doesn't take long for them to end up being cheaper then the old throw away alkaline for almost everything except for those few applications where alkaline still works the best like smoke detectors and such.

And I got some more charger links for you from another place that I buy battery stuff from:

https://www.batteryjunction.com/chcochfornin.html
https://www.batteryjunction.com/smx-i...charge-i2.html
https://www.batteryjunction.com/smx-i...charge-i4.html
https://www.batteryjunction.com/tpec-ttg2800.html
https://www.batteryjunction.com/8800.html
https://www.batteryjunction.com/titanium-md-1600l.html
https://www.batteryjunction.com/vav10baysmch.html
https://www.batteryjunction.com/tpec-tp1hr.html
https://www.batteryjunction.com/md-3000-charger.html
https://www.batteryjunction.com/vabcunsmch.html
https://www.batteryjunction.com/tpec-ttg3000.html

All those are true smart chargers with individually controlled charging slots. First one on the list is the same CH-V3150 charger that I bought several of from Battery Space (.com) other then that the only one I own personally is the IntelliCharge-i2 but I mainly use it to charge LiIon batteries (Battery Junction is where I have bought most of my LiIon batteries because they carry so many quality protected cell versions for a reasonable price) although it is capable of charging NiMH as well.

Many thanks again, turbo1889. Very helpful tip to have 3 extra batteries handy. I have bookmarked this thread for future reference!

Some other chargers at Battery Space that although I have no personal experience with directly are indeed true smart chargers with individual charge circuits:

https://www.batteryspace.com/ch-v6280...batteries.aspx
https://www.batteryspace.com/bc1huuni...batteries.aspx
https://www.batteryspace.com/ch-v6988...rycharger.aspx
https://www.batteryspace.com/ch-v9688...-celisted.aspx

And here is one one cheap one I found on amazon that is a true smart charger with individual charging cirucits (NLee the Engineers review has all the critical info). The batteries that come with it are not anywhere near up to Eneloop standards but you could just charge them up and them put them in a remote control or something as an extra that doesn't cost you anything extra:

https://www.amazon.com/Sony-BCG34HLD2.../dp/B003GS6FIE

Though I should note a correction here. The low self discharge NiMH batteries in question that can hold their own with the Eneloop batteries are specifically the "Tenergy" brand name specifically the "Centura" product line (they have multiple lines of various types of NiMH batteries). Sometimes they can be purchased for cheaper then the Eneloop batteries and more importantly the Eneloop batteries are only available in AA and AAA sizes where as the Tenergy Centura batteries are available in AAA, AA, C, D, & 9V sizes. The only thing I would note where they don't hold up in comparison to the Eneloop batteries is that you will get slightly more "problem child" cells from them. With the Eneloop batteries you will only get one or two problem child cells out of a hundred. By a "problem child" cell I mean a new cell that is lazy and doesn't want to take a full charge and must be cycled several times and worked into shape on a charger that has a function for this purpose. This is not the same as old cells that have been used for years with hundreds of cycles on them that start doing the same sort of thing; those are "grumpy oldies", I'm talking about new cells out of the package that don't want to do their fair share of the work. With the Tenergy Centura cells the "problem child" rate is probably about double that of the Eneloop batteries which is still only three or four cells out of a hundred and isn't really a big deal but should mention it as the one down side I have encountered with them being the one other brand that can hold their own head to head against the Eneloop batteries.

https://search.store.yahoo.net/thesho...horelinemarket

I want to give that Sony charger a +1. It is my favorite budget charger you can get for cheap (and with free shipping).