Longest lasting (backpack) low lumen light?

[uplite]

The original stats with alkalines was 200 hours of run time. My assumption is that this will be higher with the Eneloops.

Actually it will be higher with alkalines...they give about 40% more power than eneloops at low current.

With a high-power light, eneloops might catch up to alkalines. But they still suck compared to normal NiMH cells (non-LSD). The only reason to use eneloops is if you keep a high-powered light in storage for several months at a stretch, then grab & go without recharging. Otherwise alkalines, lithium primaries, or standard nimh cells are all better choices.

-Jeff

 

[Marduke]

Actually it will be higher with alkalines...they give about 40% more power than eneloops at low current.

With a high-power light, eneloops might catch up to alkalines. But they still suck compared to normal NiMH cells (non-LSD). The only reason to use eneloops is if you keep a high-powered light in storage for several months at a stretch, then grab & go without recharging. Otherwise alkalines, lithium primaries, or standard nimh cells are all better choices.

-Jeff

Partly true. At even a mild current draw alkalines take a nose dive and almost any NiMH cell (including LSD) will whoop it. Alkaline only push ahead at EXTREMELY low current. Unless you are powering a TV remote control, alkalines are never a better choice.

Now, for the second part, there are a number of reasons to still pick LSD cells (especially Eneloops) over high capacity cells. Shelf life is only ONE of their advantages.

I suggest you read up next time before making such definitive (and uninformed) statements.

 

[Jida]

Either way, I am 'testing' it 🙂

Should take at least 8 days from now to die off. If it drops to a very low light level I will consider that dead as well.

I think my only concern is that it is (4) cells and the draw could take each battery below the protected level. Not 100% sure on that one, just something I read here once.

 

[Marduke]

Periodically check them with a voltmeter and make sure you don't go below 1.0v and you'll be fine.

However, don't expect 200 hours. Those sorts of runtimes for cheap lights are extremely unrealistic. I would expect a much shorter period of full output, followed by a trailing period of a "moon mode".

 

[Jida]

I am going to do just that, if it goes down to a lower light output then I will consider it done.

It is standing strong right now at 4 hours of being continuously on.

If I get 100 hours of good light then it is no better than a single AA (since this uses 4 AA's).

If I get 150 hours it is a little better but maybe not compelling.

200 hours? That is getting into a really good range.

I still think the Zebralight will outdo it with (4) AA's cycling through it though and for much less weight/space.

 

[uplite]

Partly true. At even a mild current draw alkalines take a nose dive and almost any NiMH cell (including LSD) will whoop it. Alkaline only push ahead at EXTREMELY low current. Unless you are powering a TV remote control, alkalines are never a better choice.

Now, for the second part, there are a number of reasons to still pick LSD cells (especially Eneloops) over high capacity cells. Shelf life is only ONE of their advantages.

I suggest you read up next time before making such definitive (and uninformed) statements.

Hey, chill out, buddy. 😀 If you have some real info or numbers to contribute, I'm all ears. But here are some facts:

1. If a light runs for 200 hours on AA cells, it is drawing around 10mA.
2. Duracell AA alkaline has about 2200mAH at 10mA. 2200mAH * 1.5V = 3.3 watt-hours.
3. Eneloop AA NiMH has about 2000mAH * 1.2V = 2.4 watt-hours.
4. 3.3 is about 40% more than 2.4.

So it looks like alkaline whoops eneloop by a large margin in this case.

Am I missing some important detail? Or is this an "IQ inversely proportional to post count" situation? 😉

-Jeff

References:
http://www.duracell.com/oem/primary/alkaline/alkcapacity.asp
http://www.duracell.com/oem/productdata/default.asp
http://www.eneloop.info/products/manuals-and-catalogue.html

 

[Marduke]

Hey, chill out, buddy. 😀 If you have some real info or numbers to contribute, I'm all ears. But here are some facts:

1. If a light runs for 200 hours on AA cells, it is drawing around 10mA.
2. Duracell AA alkaline has about 2200mAH at 10mA. 2200mAH * 1.5V = 3.3 watt-hours.
3. Eneloop AA NiMH has about 2000mAH * 1.2V = 2.4 watt-hours.
4. 3.3 is about 40% more than 2.4.

So it looks like alkaline whoops eneloop by a large margin in this case.

Am I missing some important detail? Or is this an "IQ inversely proportional to post count" situation? 😉

-Jeff

References:
http://www.duracell.com/oem/primary/alkaline/alkcapacity.asp
http://www.duracell.com/oem/productdata/default.asp
http://www.eneloop.info/products/manuals-and-catalogue.html

First, I can guarantee you the light does NOT draw 10mA to start with. That 200 hour figure most likely came with XX hours at peak output (much higher current), and 100+ of a VERY dim moon mode.

Secondly, your voltages are wrong... alkaline nominal voltage is not 1.5v under load, more like 1.2-1.3v with a continual slope. Also, the capacity under a higher load will be significantly less. NiMH is typically ~1.3v under load with a very flat discharge profile, giving your higher performance over the discharge.

Third, you can use the Eneloop 1000 times, meaning over the life of the cell it will give you HUNDREDS of times the capacity... 😗

 

[uplite]

First, I can guarantee you the light does NOT draw 10mA to start with. That 200 hour figure most likely came with XX hours at peak output (much higher current), and 100+ of a VERY dim moon mode.

Yeah, that's possible. If this is a cheapo direct-drive light, it might start bright at a higher current, then fade down. I was just using the OP's numbers (200 hours, 7-10 lumens) since I don't have one of these lights. Do you have one?

Secondly, your voltages are wrong... alkaline nominal voltage is not 1.5v under load, more like 1.2-1.3v with a continual slope. Also, the capacity under a higher load will be significantly less. NiMH is typically ~1.3v under load with a very flat discharge profile, giving your higher performance over the discharge.

We are talking about low load here, not high load. At 10mA, alkaline voltage should stay higher than nimh voltage for pretty much the entire runtime. And the alkaline has higher mAH capacity than an eneloop. So it wins on both counts. :thumbsup:

Third, you can use the Eneloop 1000 times, meaning over the life of the cell it will give you HUNDREDS of times the capacity... 😗

OK...but this thread is about long runtime, not battery cycle life. Might want to "read up" before you post. :laughing: 😉

FWIW, I only use lithium primaries and nimh secondaries in my lights. And if I stashed a light in a BoB, there is no way in h*ll I would put rechargeables in it. That light needs to be ready to go in an emergency. Lithium primaries only.

Hope that helps to clarify. :grouphug:

BTW...marduke...you said there are a "number of reasons" to pick eneloops over high-capacity nimh cells. I have been avoiding eneloops because their capacity sucks, and I don't need their LSD. What are the other benefits?

-Jeff

 

[Marduke]

BTW...marduke...you said there are a "number of reasons" to pick eneloops over high-capacity nimh cells. I have been avoiding eneloops because their capacity sucks, and I don't need their LSD. What are the other benefits?
-Jeff

higher nominal voltage under load which partly makes up for lower capacity by having higher Wh and gives you superior performance curve during discharge, lower internal resistance, higher temperature tolerance, consistant performance over hundreds of cycles (vs diminishing performance after just a few cycles), higher tolerance to abuse (more robust), higher cycle life

there is a reason Eneloops are by far the most recommended.

Consumer rule #1
never just look at the number on the label. There is a whole lot more to a product than a single number.

 

[Jida]

I used them on recommendations here and that they work well with a solar charger.

I am still carrying 1 lithiums right now out of curiosity though.

 

[uplite]

higher nominal voltage under load which partly makes up for lower capacity by having higher Wh and gives you superior performance curve during discharge, lower internal resistance, higher temperature tolerance, consistant performance over hundreds of cycles (vs diminishing performance after just a few cycles), higher tolerance to abuse (more robust), higher cycle life

Well...according to Sanyo, the Eneloop cells, 2500mAH cells, and 2700mAH cells all have the same voltages, same internal resistance, and same temperature tolerances. Here are the datasheets:

http://battery.sanyo.com/en/spec/twicell/HR-3UTG.pdf
http://battery.sanyo.com/en/spec/twicell/HR-3U2500.pdf
http://battery.sanyo.com/en/spec/twicell/HR-3U2700.pdf

Also, a guy on CPF did some Eneloop vs 2700 tests that showed the same voltages under load. And he found that the Eneloop self-discharge rate was just slightly better than 2700mAH cells! :huh:

As for cycle life, when the eneloops first came out, I remember reading that they had fewer cycles than normal NiMH cells...but I can't find that link right now. :thinking:

Do you have links to data? Any numbers or graphs? If not...I wonder if the eneloop "benefits" are mostly forum folklore, passed on from newbie to newbie... 😗

there is a reason Eneloops are by far the most recommended.

Yup. It's called branding. 🙂 Sanyo made these cells very recognizable...so more people identified them and bought them...and most people believe that what they bought is the best. :laughing: Caveat emptor...


Bottom line...back on topic...I would not choose eneloops for a very low, very long runtime light. Lithium primaries are better for storage, and high-cap nimh cells are better for runtime. YMMV. 🙂

-Jeff

 

[Woods Walker]

ZL H50 or H501 (w) would be the way to go for loooooooooooog run time on low. The 3ish lumens is brighter than one would expect in the dark dank woods. The iTP 3-mode EOS has a 1.5-2 lumen low that runs a looooooong time but this is 1xAAA.

 

[Marduke]

Well...according to Sanyo, the Eneloop cells, 2500mAH cells, and 2700mAH cells all have the same voltages, same internal resistance, and same temperature tolerances. Here are the datasheets:

http://battery.sanyo.com/en/spec/twicell/HR-3UTG.pdf
http://battery.sanyo.com/en/spec/twicell/HR-3U2500.pdf
http://battery.sanyo.com/en/spec/twicell/HR-3U2700.pdf

Also, a guy on CPF did some Eneloop vs 2700 tests that showed the same voltages under load. And he found that the Eneloop self-discharge rate was just slightly better than 2700mAH cells! :huh:

As for cycle life, when the eneloops first came out, I remember reading that they had fewer cycles than normal NiMH cells...but I can't find that link right now. :thinking:

Do you have links to data? Any numbers or graphs? If not...I wonder if the eneloop "benefits" are mostly forum folklore, passed on from newbie to newbie... 😗

Yup. It's called branding. 🙂 Sanyo made these cells very recognizable...so more people identified them and bought them...and most people believe that what they bought is the best. :laughing: Caveat emptor...


Bottom line...back on topic...I would not choose eneloops for a very low, very long runtime light. Lithium primaries are better for storage, and high-cap nimh cells are better for runtime. YMMV. 🙂

-Jeff

There is plenty of test data to back it up. The spec sheets are the same because Sanyo would have to do a LOT more work to show their homolattice cells are in fact better, which would have received a lot of industry pushback for what should have been a "regular NiMH" cell, and could have involved publishing trade secrets. So it was faster and cheaper to use industry standard specs since they are conservative.

CPF testing has show them to be much better.

As for self discharge, they discharge faster for the first month, then level off to almost none thereafter, where high capa loose ~30% or MORE for every month WHEN THEY ARE NEW. With age, they can self discharge in a number of weeks or even days, accumulating higher internal resistance and lower capacity with every cycle.

In the end, the ONLY thing high cap cells are better at is higher INITIAL capacity when they are relatively new. EVERYHING else Eneloop wins.

No offense, but you have been here for less than two months. CPF has been disecting every aspect of these cells for something like 4 YEARS. We don't THINK they are the "best" because of some flashy ads, we KNOW they are the best from years of INTENSIVE testing by some VERY smart people, some of which have forgotten more about battery tech than I will ever know.

 

[berry580]

My Duracell Rechargeables drop from 1.4V to ~0.9V within a month. Its new, probably charged it for less than 20 times in total. It just totally sucks.

I don't have any eneloop AAs, but i do have some eneloop AAAs, and NOTICEABLY hold charge better than any other AAA rechargeables i have. (includes Energizer, Fujicell, Sanyo 900, Tenergy).

Once fully charged @ ~1.4V, the eneloop AAA stays over 1.35V, while the rest drops to somewhere between 1.3V-1.35V within a few days.

This claim of holding 85% charge in 1/2 year is fking deceiving. 85% of 1.4V is 1.19V, which is fking next to useless.

 

[Marduke]

My Duracell Rechargeables drop from 1.4V to ~0.9V within a month. Its new, probably charged it for less than 20 times in total. It just totally sucks.

I don't have any eneloop AAs, but i do have some eneloop AAAs, and NOTICEABLY hold charge better than any other AAA rechargeables i have. (includes Energizer, Fujicell, Sanyo 900, Tenergy).

Once fully charged @ ~1.4V, the eneloop AAA stays over 1.35V, while the rest drops to somewhere between 1.3V-1.35V within a few days.

This claim of holding 85% charge in 1/2 year is fking deceiving. 85% of 1.4V is 1.19V, which is fking next to useless.

there is no easy correlation between voltage and state of charge for NiMH cells. A 90% full cell and 90% empty cell might only be seperated by <.1v.

BTW, it's 85% after 1 year, not 6 months.

 

[Lynx_Arc]

My Duracell Rechargeables drop from 1.4V to ~0.9V within a month. Its new, probably charged it for less than 20 times in total. It just totally sucks.

I don't have any eneloop AAs, but i do have some eneloop AAAs, and NOTICEABLY hold charge better than any other AAA rechargeables i have. (includes Energizer, Fujicell, Sanyo 900, Tenergy).

Once fully charged @ ~1.4V, the eneloop AAA stays over 1.35V, while the rest drops to somewhere between 1.3V-1.35V within a few days.

This claim of holding 85% charge in 1/2 year is fking deceiving. 85% of 1.4V is 1.19V, which is fking next to useless.

I think the claim is more like 85% USEFUL charge. that would be something like 85% of 1.1-1.35v or 0.85x0.25v=1.3125v etc... essentially I would guess a battery would be around 1.3v after that period of time vs 0.9v after a week from many high capacity non LSD cells. I have some new, unused rayovac hybrid cells that measure 1.26v I bought over a year ago and never charged.
I take that back.... I bought the hybrids in march 2007 and never used some of them so they are about 2 1/2 years old and only charged from the factory so that could be perhaps 33 months without a charge?

 

[geepondy]

I saw one suggestion for it earlier but if you can live with it being over priced, I too would suggest the 9V Pak-lite. I would guess that on high (two 5mm LEDs), it's probably about ten lumens. For a bug out bag, I'd slap on a Ultralife lithium 9V battery where the web site claims 80 plus hours on high and 1200 plus (that's what they claim) hours on low. That's 50 days. Another advantage I find that it's generally easier to read with a square or flat type light as it doesn't roll around as easily.

 

[uplite]

There is plenty of test data to back it up
...
CPF testing has show them to be much better.
...
CPF has been disecting every aspect of these cells for something like 4 YEARS

OK...got links? I already searched for test data, and what I found from both the manufacturer and CPF did not agree with your claims. Maybe I looked in the wrong place. Where is this other test data? Thanks. 🙂

We don't THINK they are the "best" because of some flashy ads, we KNOW they are the best...

:laughing: I wonder how many lumens we could get from a faith-powered flashlight. 😉

-Jeff

 

[defloyd77]

How does the Pak-Lite compare to the PALight? I'd definately feel more confident with the PAL as it protects the battery.

 

[Marduke]

OK...got links? I already searched for test data, and what I found from both the manufacturer and CPF did not agree with your claims. Maybe I looked in the wrong place. Where is this other test data? Thanks. 🙂
-Jeff

Lots of sickies in the battery forum, and you choice of TWO search engines.

Or you could spend two years reading all pertinent threads like I did and get back to me when you're done....

Edit:
About 30 seconds worth of Google-foo...
http://www.eneloop.info/fileadmin/EDITORS/ENELOOP/ARTICLES/Teraoka_Article_EN.pdf
http://www.candlepowerforums.com/vb/showthread.php?t=219301

higher voltage - check
lower internal resistance - check
higher tolerance to extreme environments - check
higher voltage under load - check
self discharge plateau - check
longer cycle life - check
Actually have higher total power than "high capacity cells" after 100-200 cycles - check

Did I miss anything?? 😗