Lasting flashlight/lantern

[kamen]

Hello

Your forum is interesting
I'm looking for advice how to select lasting flashlight/lantern
I wish to use 4xAA NiMH low self-discharge batteries because seem the best choice for long term
My experience is limited to wikipedia and what I read in another forum
I understood that polarity reversal can cause permanent damage to the batteries

So I'm wondering whether there are flashlights/lanterns for 4AA that cutoff to prevent over-discharging/polarity reversal

I looked at several sites and I do not see infromation about this

Can you recommend link where to read?

Also I'm looking for other usefull advices like what batteries to select: sanyo eneloop or sony cycle energy

By the way I see that I can help you to post the collection of runtime graphs
http://www.candlepowerforums.com/vb/showthread.php?t=216438

I created for several minutes script that takes the data from text file and makes chart that can be posted as image on the web
In order to use it is nessesary just to ftp the data files to the web server and type the file name in the image tag
http://kamen123.awardspace.com/chart/ch.php?file=file.txt

I think such script will save time and will allow easier posting of the graphs. If you like it I'll send you a copy for the forum here

Thanks in advance for the help

Kamen

 

[Turbo Guy]

Sanyo Eneloops and Rayovac Hybrids are very good choices. They are LDS(low self discharge) so they maintain their charge extremely well for months on end and so are ready when needed.

There is a ton of AA flashlights however most are for one or two cells. IMO the TerraLux LightStar 220 EX is a very good inexpensive one. It use two AA and has two levels. Hi is rated at 220 Lumens 1 -1/2 Hrs. and Low 100 Lumens 6 hours.

 

[kamen]

Thanks for the advice

In the stores near me I did not see Rayovac Hybrids so I assume the best choice is Sanyo Eneloops

About runtime: I'm looking for long lasting: 10...100+ hours

And I'm wondering whether there is auto cutoff/stop available. Because I like careless use. For example if I forget the light on or if give it to someone without experience with NiMH batteries

 

[Turbo Guy]

What will this light be used for mostly?
In general you will not get a great deal of light output from AAs for such extended times.

There are many 2 AA lights which have approx. 60 to 100 lumens output using approx. 250 mAh (1/4A) on low output level. Such lights will operate for approx. 6.8 hours (1700 mah/250mA) and then just slowly get dimmer and dimmer.

There are ones with lower output on low power that will last longer but it may or may not be enough light for your needs. It is simple enough to have spare cells and charge them as needed. During prolonged power outages they can be charged using a charger that can be powered from 12 volts so that any car,truck,SUV can be used as a power source or eve a spare 12 volt battery or one of the many Jump Start unit sold for emergency auto starting.

 

[kamen]

Well I do not plan to compete with cars so I'm not looking for bright light.

I wish simple, lasting and reliable light.

For the moment I think the best choice for me is something like these

http://www.dorcydirect.com/p-192-41-2498-25-lumens-4aa-led-floating-flashlight-w-batteries.aspx

http://www.dealextreme.com/details.dx/sku.20343

http://www.dealextreme.com/details.dx/sku.15755

with auto stop to protect from over-discharging/polarity reversal

It is surprising to me that there are so many texts about different flashlights and about different batteries but I did not find text about auto stop flashlight to protect NiMH cells

 

[Phaserburn]

A super long lasting, not too bright lantern that is meant to run on nimh cells with a protection circuit isn't going to be easy to find. A lantern like that would be designed to run on alkalines, and even if it had a protection circuit, it would get significantly longer runtimes on alks as they have greater capacity than does nimh AAs (the lsd variety, around 2000-2100mah; alks have 2900mah) when the current draw is low (like you're stipulating). In short, the purpose and design of the lantern you're looking for is at odds with nimh vs alk attributes.

 

[rmteo]

To get 100+ hours of run time from AA's, you are limited to <20mA of current draw. At this level, the amount of light is going to be very low - probably 5 lumens or less. To get the long run times you are looking, you will need to look at higher capacity batteries.

This is what I use for a general purpose light. It takes 2x D-size 10000mAH NiMH cells. It has 4 levels of output. Current draw is:
Level 4- 0.70A - 14.5 hours
Level 3 - 0.38A - 26.3 hours
Level 2 - 0.24A - 41.7 hours
Level 1 - 0.07A - 140+ hours

At the highest level, it puts out about 90-100 lumens (not measured, but compared to my other lights) and about 10-15 lumens at the lowest level - still very useable. I modified the light with a connector (circled in red) to allow charging without having to remove the batteries from the light. The light normally sells for $25 but you may be able to get one at some Target stores now for $7.98 on closeout. There is a review of the light here:
http://www.candlepowerforums.com/vb/showthread.php?t=193331

 

[kamen]

it would get significantly longer runtimes on alks as they have greater capacity than does nimh AAs

Well looking at http://www.flashlightreviews.com/reviews/lri_proton.htm
I see that 2300mAh NiMH lasts longer.

It seems that with 2000mah nimh AA lsd the runtime will be the same or longer than alkaline. Not 'significantly longer runtime on alks '

Also I have seen other related chart at flashlightreviews.com

The cost of protection circuit can be about $1-2 and can save many NiMH cells

Am I right?

I still do not see reason why is not available

 

[Turbo Guy]

see post here

http://www.candlepowerforums.com/vb/showpost.php?p=2907968&postcount=2

why low voltage protection is in general not needed with NiMH cells / batteries in flashlights and most consumer electronics.

 

[kamen]

low voltage protection is in general not needed with NiMH cells / batteries in flashlights and most consumer electronics

This is in contradiction with the other post:

Most consumer electronics will shut down when the battery reach approx. 1.1 volt per cell so no problem. Some LED flashlights will drain them to a very low level. The only real problem is if(when) one cell goes to zero and then the other cells will reverse charge it.

?

 

[Phaserburn]

Well looking at http://www.flashlightreviews.com/reviews/lri_proton.htm
I see that 2300mAh NiMH lasts longer.

It seems that with 2000mah nimh AA lsd the runtime will be the same or longer than alkaline. Not 'significantly longer runtime on alks '

Also I have seen other related chart at flashlightreviews.com

The cost of protection circuit can be about $1-2 and can save many NiMH cells

Am I right?

I still do not see reason why is not available

The light you've linked is NOT a low current draw; it's high. When current draw is high, nimh cells do last longer than alks. Alks cannot release all of their capacity under high drain because of high internal resistance. Nimh have much lower resistance, and can release their capacity pretty much regardless of the drain.

For example: I have a led lantern that uses 3C cells. On low, it draws around 50ma, IIRC. This is a low current draw, and will allow alkaline cells to give up all of their capacity. Nimh cells are around 5Ah; alk Cs are around 8Ah+. So, you can do the math and see that the alks will last alot longer than nimh, and without risk.

 

[kamen]

alks will last alot longer than nimh, and without risk.

I see, I found another chart at http://www.flashlightreviews.com/reviews/fenix_l1dce-l2dce.htm
At L1D LOW Runtime the runtime of alk and nimh is almost the same so with 2000 mah nimh obviously the runtime will be shorter

Probably the best choice for me is Maglite MiniMag LED or something similar
http://www.flashlightreviews.com/reviews/maglite_minimagled.htm
Looking at the chart I assume that has protection circuit. Also I read somewhere that Maglite has smooth regulation of the light, so if I select lowest mode I'll get 30-50 hours

Am I right this time?

 

[rmteo]

That MiniMAG is a single mode light.

It will run almost 3½ hours before reaching 50% starting output. At about 3:45, output drops to almost nothing, indicating it is time to change the batteries.

 

[kamen]

That MiniMAG is a single mode light.

I see, I looked again at maglite.com

So probably the best choice for me is 3-mode 1AA flashlight and to take with me several charged nimh cells, this way I can use the great value of lsd and I'll be sure that if I give the flashlight to someone he will not spoil the cell

When I have time I may make my controller for nimh lsd with cost $1-$2 and may be sell it to some manufacturer

 

[rmteo]

The LumaPower Connexion X2 may work for you. It takes a single AA battery and sells for $50 from Battery Junction. Here is some data on it.

Output/Runtime(100% to 50%):
(Alkaline): 100 lumens/35 minutes, 25 lumens/7+ hours, 4 lumens/71+ hours.
(Energizer E2 Lithium): 100 lumens/94 minutes, 25 lumens/8 hours, 4 lumens/80 hours.
(NiMh 2700mah): 100 lumens/110 minutes, 25 lumens/7 hours, 4 lumens/70 hours.
(Li-Ion 14500): 120 lumens/95 minutes, 28 lumens/7+ hours, 6 lumens/40+ hours

There is also a 2xAA extension tube available for it that will pretty much double the runtime to 140 hours. See here:
http://www.candlepowerforums.com/vb/showthread.php?p=2907938#post2907938

Good luck on selling your gizmo.

 

[kamen]

Good luck on selling your gizmo.

Thanks. First I need to find time to make it. Because I have many other ideas. Anyway I'm sure that in the next several years someone will make it because the technology is available. It is just matter of planning and testing. May be name and functionality will be similar to digital flashlight

 

[Turbo Guy]

This is in contradiction with the other post:



?

I see no cotradiction.

As stated most consumers electronic devices will shut down at approx. 1.1 per cell.

Flashlights are an exception. Some such as an LED Mini mag will also just shut off however some will drain cells lower.

Snip from anothe post of mine:

As a test I discharge two AAs to 0.9V on MahaC-900 @ 500 mAh rate. I then repeated using 200 mAh rate. I then placed them in a TerraLux 220EX and they maintained decent output on high for 20 minutes,at 25 min. I could not tell any difference between Hi and low but I left set on high and after 40 min. total the light was getting fairly dim. I would guess approx. 20 lumens (based on other lights ratings). When I stopped the test one cell was 0.9V and the other 1.12V.

Those cells werey sorry,old cheap NiMh cells that are way past their prime. No harm was done to the cells.
Another point is that were are talking about fairly inexpensive cells here. Sanyo Eneloops at 4 for $10 will last hundreds of cycles perhaps as many as 500 in normal useage. If drained to 0.9 volts in a LED flashlight every time they may only last 50 cycle but that is still only $0.05 per cell per cycle.


If you are really concerned about overdischaring then there are LED flashlight with indicators or digital displays to show remaing battery capacity. Most of use with any experience have learned that for the most part simplier is better. You can tell when a light is getting dimmer and needs fresh cells.
One exception is the original MiniMag LED which just shuts off without warning. I know I carried one for several years as my EDC. The TerraLux 220EX is ten times better. More ligh even on low,more run time and does not just leave you in the dark all of a sudden and on high is as powerful as much more expensive light and in fact is more powerful than a large MagLite with a Mag LED dropin.

 

[kamen]

thank you for the information

I'll look and select several 1AA flashlights to test

 

[kamen]

Your comments are useful to me.
I spent more time thinking.

Sanyo Eneloops at 4 for $10 will last hundreds of cycles perhaps as many as 500 in normal useage. If drained to 0.9 volts in a LED flashlight every time they may only last 50 cycle but that is still only $0.05 per cell per cycle. If you are really concerned about overdischaring then there are LED flashlight with indicators

Well $0.05 per cell per cycle is low cost and is not much

However wish a protection circuit(between $0.5 and $1) the cost can be $0.005 per cell per cycle, another advantage is careless use

To me still is good idea to add protection circuit in any flashlight/lantern. For long term a protection circuit can save many batteries and a lot of time