Absolute Limit of 1AA light?

With the AA battery being probably the most common worldwide, and with the variety of AA types (NiMH, alkaline, Lithium Primary, not even getting into lithium ion rechargeables), AA lights are my preference.

And as we know, emmiters continue to get brighter and more efficient.

So what would be the theoretical (or practical if you'd rather) limit of a AA light? The answer will have to be a combination of output and runtime. We'd likely have to make some assumptions/constraints such as...

Battery - say a 2000 mAh NiMH (ie Eneloop)
What current draw is placed on battery
Overall Efficiency

It would just be intersting to know how far LEDs and flashlights have to progress still. Is 500 lumens for 1 hour possible from a single AA Eneloop, or are there not enough electrons available in an Eneloop to produce the necessary photons?

Matt

We're at about the limits now, if not past them.

I started out being a AA-only man myself for the same reasons. In the past year, there have been HUGE advancements. JetBeam announced a couple new lights a month or two ago (which should be shipping this week). One of them was a AA based light which was going to have a Rebel100 emitter in it. After testing, they went with a Cree Q4. Why a Q4 and not a Cree Q5 or the original Rebel? According to them, the Rebel wasn't performing "satisfactorily" and the Vf requirements of the Q5 were too much for a single AA cell, so they went with the Q4.

Fenix has a Rebel80 in the L1T, and not a Rebel100.

I'm not a technogeek at all, and don't even know what Vf is... but what all of that tells me is this:

We have emitters that are brighter and more efficient - which are being used in single 123 cell lights - which are not being used in AA cell lights. Therefore, the battery must be limiting the emitters we can use, and therfore the light that can be put out.

I would love to see/have a 200 lumen single AA pocket-rocket. Unfortunately, it's looking like 90 lumens is about the barrier for the single-AA format at this point, and 500 lumens may never be attainable.

mchlwise said:

I would love to see/have a 200 lumen single AA pocket-rocket. Unfortunately, it's looking like 90 lumens is about the barrier for the single-AA format at this point, and 500 lumens may never be attainable.

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Well... as efficiency improves, LEDs with relatively low Vf may provide more light at the same V + Current draw as the current ones used in AA lights.

What we CANNOT expect, is to draw any more power from AAs then we already do now...

Then again, we've already pretty much surpassed the ability of alkaline AAs to cope with load, because they exhibit insane voltage sag under high loads in single AA lights, which results in dramatically reduced runtimes compared to AA NiMH batteries (as much as a 75% or four-fold reduction).

Well, with a great driver, like the RV7 driver, you could be getting over 1 amp at the LED if you use a good NiMh battery. So I think that would be close to the limit.

I have heard about circuits that can deliver 600ma to the emitter via an NiMH cell with a reasonable efficiency. I'm wondering why no multilevel lights exist with this high of a current. Maybe its the inability to use alkaline?

Hope we continue to see AA limits explored

Good thread, I just got into these forums and the whole non over the local counter flashlight purchase/options/performance etc.

My other key items in routine travel use AA's as well so I've got lots of batteries/15 min. power charger for NiMH's etc. I see their are some lights but not many in the smaller setup's for AA's.

I'd love to see a 100 lumen's + single or double (or triple in a bundled configuration) AA crenelated bezel light....

(I'm still researching the mag mod's with the AA pack's etc...).

Re: Hope we continue to see AA limits explored

Westy said:

I'd love to see a 100 lumen's + single or double (or triple in a bundled configuration) AA crenelated bezel light....

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This will probably interest you. And it's a very good circuit from what I understand, I believe it's basically the same circuit as RV7's with more modes - it should be over 100 lumens.

https://www.candlepowerforums.com/threads/178256

I was wondering if the AA alkaline has seen it's time pass - the performance in high drain applications is quite limiting. I only have a Liteflux LF5 P4 which is pretty darn bright on high power - running on NiMH or Lithiums at least - with decent runtime. It does seem like we're approaching the limits of what the standard cells.

However, the LF5 will take 14500s so I'm about to buy a few to test them out - I expect a fairly significant increase in output based on Selfbuilt and others test results - so it makes me wonder a bit if 14500 based 3.7v lights might eventually take a chunk out of the 123 based pocket light market - since they may be a bit longer but typically a fair amount thinner (which in my pockets matters more). I don't know what the capacity is between a 14500 and an RCR123 but I'd guess teh 14500 has more oomph to it as well...

Even thought they have such limitations AA will remain my favorite until the cost of 123's are comperable at local B&M stores. That and AA are free at work!:nana:

mchlwise said:

I would love to see/have a 200 lumen single AA pocket-rocket. Unfortunately, it's looking like 90 lumens is about the barrier for the single-AA format at this point, and 500 lumens may never be attainable.

Click to expand...

200 lumens will definitely happen, and probably not before too long - with something like a Cree R4/R5 and a circuit like RV7's, it might be possible even. 500 lumens will probably happen in time as well IMO. Think about something like a tri-Rebel light, or a future LED that uses 3 or more dies in a very small package. When efficiency can approach 150+ lumens/watt, you'll then be approaching that 500 lumen mark on paper anyway. It's just a matter of time in my opinion.

Re: Hope we continue to see AA limits explored

You can get a about 2 watts for one hour out of a single AA. The best LEDs are a little better than 100 Lm/W and a converter efficiency of about 90% is possible.

That gives you about 200 Lumens as the theoretical maximum for 1 hour with todays technology.

Re: Hope we continue to see AA limits explored

Ron Schroeder said:

You can get a about 2 watts for one hour out of a single AA. The best LEDs are a little better than 100 Lm/W and a converter efficiency of about 90% is possible.

That gives you about 200 Lumens as the theoretical maximum for 1 hour with todays technology.

Click to expand...

It also depends on how hard you want to run the LED. If you wanted to run the LED at its maximum rated current of 1A (about 3.6 watts), a Cree Q5 LED puts out only about 67 lm/W at that current. And it would require about 3A from the AA cell. I don't have any ready data on AA NiMH capacity at 3A, but suppose it would still be not too much less than 2 Wh. So at 90% converter efficiency (very hard to do with a 1.5 volt supply and 3A input current in a small size), that would give you about 240 lumens at the LED (around 180 out the front) with a run time of a half hour. The weak point in this theoretical analysis is the 90% assumption. Besides the difficulty in making a small regulator with that efficiency, you'd also have to take care to keep the resistance of the battery current path very low. At 3A and about 1 volt, every 3 milliohms of resistance would cost you about an additional percent of efficiency. 15 or 20 minutes is probably a more realistic run time at full LED output.

c_c

Re: Hope we continue to see AA limits explored

mmmflashlights said:

This will probably interest you. And it's a very good circuit from what I understand, I believe it's basically the same circuit as RV7's with more modes - it should be over 100 lumens.

https://www.candlepowerforums.com/threads/178256

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Many thanks! Looking fwd to seeing more posts on that thread. Thanks again.

Gatsby said:

However, the LF5 will take 14500s so I'm about to buy a few to test them out - I expect a fairly significant increase in output based on Selfbuilt and others test results - so it makes me wonder a bit if 14500 based 3.7v lights might eventually take a chunk out of the 123 based pocket light market - since they may be a bit longer but typically a fair amount thinner (which in my pockets matters more). I don't know what the capacity is between a 14500 and an RCR123 but I'd guess teh 14500 has more oomph to it as well...

Click to expand...

My EDC is a LiteFlux LF5, with a 14500 in it. The reason for that is that it gives me REALLY close to the performance I would get from a single 123-based light, but if there is some emergency and I need to replace the battery, I can grab one from a remote control, or a kids toy, or just about anywhere - which can't be said for 123 cells.

As far as capacity, I just took out the 14500, and it says 900mah. The R123s I got from DealExtreme yesterday say 800mah on them... so I'd say they're pretty comparable.

Re: Hope we continue to see AA limits explored

Westy said:

...I'd love to see a 100 lumen's + single or double (or triple in a bundled configuration) AA crenelated bezel light....

Click to expand...

Well, 2 AA can easily hit over 100 Lumen out the front, the Fenix L2D-CE, L2D-Rebel 100, L2D-CE Q5, L2T V2.0 are all good examples(will hit 100 lumens even with alkaline batteries).

The main problem is getting a 1 AA light to hit over 100 Lumens out the front, which with a good driver and a good rechargeable battery, is easily possible. This driver form DX or this 1 AAA width driver(simpler version) at Kaidomain is a cheaper solution to the RV7 if you don't mind the excess amount of modes.

mchlwise said:

My EDC is a LiteFlux LF5, with a 14500 in it. The reason for that is that it gives me REALLY close to the performance I would get from a single 123-based light, but if there is some emergency and I need to replace the battery, I can grab one from a remote control, or a kids toy, or just about anywhere - which can't be said for 123 cells.

Click to expand...

That was exactly my reasoning in going for an LF5: it seems to have the best proven ability to use 14500's (safe to use with unprotected cells, but can fit protected cells, etc) combined with AA's as backup.

As far as capacity, I just took out the 14500, and it says 900mah. The R123s I got from DealExtreme yesterday say 800mah on them... so I'd say they're pretty comparable.

Click to expand...

Yes: the 900's were a pleasant surprise when I saw them online yesterday. Of course claimed and actual capacity might not be quite the same...

Re: Hope we continue to see AA limits explored

Ron Schroeder said:

You can get a about 2 watts for one hour out of a single AA. The best LEDs are a little better than 100 Lm/W and a converter efficiency of about 90% is possible.

That gives you about 200 Lumens as the theoretical maximum for 1 hour with todays technology.

Click to expand...

So we're what, almost 50% of the way to max brightness, and a bit closer again to maximum converter efficiency???

mchlwise said:

My EDC is a LiteFlux LF5, with a 14500 in it. The reason for that is that it gives me REALLY close to the performance I would get from a single 123-based light, but if there is some emergency and I need to replace the battery, I can grab one from a remote control, or a kids toy, or just about anywhere - which can't be said for 123 cells.

Click to expand...

That's good thinking.
I have 8 RCR123's which will keep me going for a long time in an emergency, but only if I'm at home when it happens.

For the record, this is a good thread!!:twothumbs

In Selfbuilt's AA review, he slapped a L2D RB100 head onto a L1D body. That combo beat out all of the other AAs regarding output. The runtime was still 2+ hours.

From what I have read, I don't know if the Q5 Cree is the Rebel killer. The Rebel can be operated in a 1AA body (because of lower Vf, I assume:thinking, while the Q5, with a higher Vf (I still don't really know what the hell the Vf does...), cannot.

We are all waiting for the next big LED jump. Moving in minute increments is not making me . My next light will finally be a Cree, then I'll be set for awhile. There was a thread with a poll asking about whether you need a big tech boost to make a purchase. Well I do. Eventually we will have those AA throwers. I don't need one yet.

Who knows, maybe 2 years from now some new, and more powerful, AA format will come out...

Re: Hope we continue to see AA limits explored

Curious_character said:

It also depends on how hard you want to run the LED. If you wanted to run the LED at its maximum rated current of 1A (about 3.6 watts), a Cree Q5 LED puts out only about 67 lm/W at that current. And it would require about 3A from the AA cell. I don't have any ready data on AA NiMH capacity at 3A, but suppose it would still be not too much less than 2 Wh. So at 90% converter efficiency (very hard to do with a 1.5 volt supply and 3A input current in a small size), that would give you about 240 lumens at the LED (around 180 out the front) with a run time of a half hour. The weak point in this theoretical analysis is the 90% assumption. Besides the difficulty in making a small regulator with that efficiency, you'd also have to take care to keep the resistance of the battery current path very low. At 3A and about 1 volt, every 3 milliohms of resistance would cost you about an additional percent of efficiency. 15 or 20 minutes is probably a more realistic run time at full LED output.

c_c

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If that is possible for a aa light than imagine with 123's. If surefire could make an L1 which is a single 123 light put out 180 lumens on high out the front, with 45 lumens on low, with 45mins of runtime on high, 1.5 hours on low, I would buy five.