The search for the USB rechargeable AA flashlight

Most common failure point on almost every cell phone is the USB charging port.

Well, just like the MecArmy and Lumintop single 18650 cell with built-in micro USB charger, it would be nice to have an Eneloop variant.

They do exists but not manufactured any more…

Niteye ec-a12
Klarus rs1a

I can not find the klarus……. only a few on ebay at impossble prices… also the niteye has bad reputation…

I hate li-ion due to dangers… thats why I dont want usb rechargeable li-ion ones… that are cheaper and easy to find

It looks like Battery Junction has the Klarus for $48. That is the cheapest I could find it in a quick search.

Shipping to europe + taxes and fees makes it about 100$

Doesn’t exist in multi-cell format.

NiMH cells in series shouldn’t be charged as a collective sum. They also can not be charged in parallel (unlike Lithium based chemistry), although I am not exactly sure why. So the design of the light overall would require all cells to be electrically isolated from one another. Its not impossible… just very complex, both physically and electrically.

[EDIT] I stand corrected… Looks like Niteye is taking a stab at it. I would question charging the cells in series though, without the circuit monitoring the cell voltage individually during charging.

https://www.amazon.com/Niteye-EC-A12-Rechargeable-Cree-Flashlight/dp/B016ARC9U0

Now that I think about it, the design wouldn’t need to be “that” complex. An over-sized light host with an internal 2AA cell caddy design could be used to isolate the cells from one another and monitor cells individually during charging.

Normally, yes. However, 9 volt NiMH batteries have 7 cells wired in series, and they have to be charged that way. It’s not ideal, but it can be done. It does result in shortened life span of the battery, as individual cells are either over-charged or under-charged.

I think you are overestimating the dangers of lithium ion. I mean, you don’t see people dying in droves by exploding cell phones right? And those are 3.7 volt, 3000mAh batteries, about the same as an 18650. As long as you are reasonably careful, you should have no issues, barring some design flaw.

The problem with 1xAAs is that they aren’t really bright enough in comparison. With only 1.2 volts to work with, and fairly limited current draw, its difficult to get enough gas to get a lot of light out of such a small light using NiMH. Granted, they have come a long ways…zebralights are pretty amazing what they do with 1xAA. But still, they are quite pricey.

For just a little bit more size an 18650 has way better power density, and much higher current draw capability and a more useful 3.7 nominal voltage.

You can also get a smaller 16340 or 18350 type light that is a bit shorter but similar power.

Curious, Where? bad reputation as in negative reviews?… or something more serious, like severely over-charging NiMH cells? The latter condition can happen when you charge 2 cells in series that do not have exactly the same actual capacity.

FWIW… you can over-charge a NiMH battery and it can vent gasses. Venting expanding gasses trapped inside a water-tight enclosure is a recipe for an explosive condition. Once the gas pressure exceeds the containment limits of the device. The difference is NiMH does not vent caustic, flammable gasses.

I have an old nimh dumb charger that charges the cells in series configuration… and it just… works… but I dont know if that would be good for batteries. Specially for lsd.

However… I always charge eneloops with smart chargers (dV and dT termination)

The niteye is tempting me despite it os nor 100% what I am searching for…. oh no! Another flashlight for my collection?? XP

I am open to new suggestions. Thanks friends

I dont remember exactly were I read about that. I think it was on cpf.

It is related to its internal charging circuitry. Some units had charge problems… I mean the charge circuit stop working forever suddenly…

I cant remember now. The niteye a12 is not a new light… it has a few years…

heheh these are the ways new BLF projects can start.
AA build in charging flashlight, sounds good

4xAA, micro-USB charging and Nichias sounds like the perfect allround flashlight for muggles. I’m sure some flashaholics would like it too, me for example. :slight_smile:

When will be available??? :smiley:

BLF AA rechargeable flashlight
+1 on a BLF project for a USB rechargeable AA flashlight, with 1, 2 or 4 batteries. Although us here probably won't either need or want this, it see it as a great item either as a gift to people unaware of potential Li-Ion issues (overcharging, accident, ...) or more simply to be used by children going on a holiday camp or anything similar. In other words taking no risk at all with the batteries/flashlight ...

Hank's 4 AA rechargeable flashlight
Hank, looking at the page your flashlight points too, I don't see any plug or info about battery recharge within the flashlight. Or what did I miss?
https://www.dorcy.com/190-lumen-led-flashlight-yellow

Existing single AA rechargeable flashlights
Now, although there seem to have been, in the past, a few single AA flashlights that could be recharged through an USB port, manufacturers don't seem to produce them anymore. And as much as as AA batteries in serial may present quite an obvious electrical issue for recharging, I'm not sure why it should be such an issue for a single AA - cost put apart. Talking about cost, now that we have very decent rechargeable 18650 flashights under $20 (best example, amongst others : Eagle Eye X2R), I'm not sure how cost would be an issue anymore. And given that micro usb chargers and cables are now widely used, thanks to smartphones, interest seem to be obvious, at least to me ...

So, is anybody aware of an existing, decent and price effective (in short: BLF friendly ) single AA rechargeable flashlight?

I think, as others have pointed out, the charging circuit for NiMH is more complex than for lithium-ion. I tend to be paranoid about lithium-ion safety, but in a single-cell format, they should be very safe, especially with good quality cells. Of course they’re used in just about every kind of rechargeable electronics nowadays.

So, I’m not sure there’s really a market for USB rechargeable NiMH flashlights. You can pack almost as much energy into a single 18650 as 4 NiMH cells, and a USB charging circuit is simple and cheap for an 18650.

As much as I like NiMH flashlights, I’d go with a single lithium-ion format if I want built-in recharging.

Otherwise, invest in a basic Eneloop+charger kit, and keep some spares charged for replacement when needed.

Just a note for those who don’t know: No, you can’t pack anywhere near as much energy into a 18650 as 4 NiMH cells. A good quality NiMH cell packs around twice the mAh at around 1/3 the voltage as a good quality Li-ion of the same size. So, one NiMH cell is 2/3 as powerful as an equivalent size Li-Ion cell. Maybe you were talking about max current draw? Li-Ion does have a definite advantage there. But, a single High-capacity (not high-current) Li-Ion could still lose to 4x Eneloop NiMH in some cases.

Huh?

NiMH (AA Eneloop): 2000 mAh * 1.2V * 4 pieces = 9600 mJ
NCR18650GA: 3500 mAh * 3.6V * 1 piece = 12600 mJ

So a single 18650 cell has more energy than 4 Eneloops me think… I think you reversed the capacity of NiMH and lithium ion.

Looking at HKJ tests, an Eneloop Pro (2450 mAh), at 1A discharge rate has an energy of 2,982 Wh.
A Sanyo NCR18650GA cell (3500 mAh), at 1A discharge rate has energy of 11,850 Wh.

So yes, a single 18650 can have roughly the same energy as 4 NiMH cells.

http://lygte-info.dk/review/batteries2012/Eneloop%20AA%20BK-3HCC%202450mAh%20(Black)%20UK.html
http://lygte-info.dk/review/batteries2012/Sanyo%20NCR18650GA%203500mAh%20(Red)%20UK.html

Alright, I did get crossed up a bit, but not in the way you think. You’re right, an 18650 Li-Ion does pretty well versus 4xAA NiMH. But, your math isn’t quite right still. The highest capacity Eneloop AA is 2450mAh. So your compare should look like this:

NiMH (AA Eneloop): 2450 mAh * 1.2V * 4 pieces = 11760 mJ
NCR18650GA: 3500 mAh * 3.6V * 1 piece = 12600 mJ

A single 18650 does beat 4xAA Eneloop. Sorry for my confusion. I was somehow thinking about size equivalence when doing my math before. :person_facepalming: