Help: Evaluate Battery Capacity

[bendlite]

I need some help sorting trough the massive amount of information available here. My wife and I are going into the jungle of South America on a two week medical mission. We will have no external source of electricity (no mains, no generator, etc.) to charge batteries during the two week period. We have to be as self-sufficient as possible.

We need (bright) lights to perform medical procedures (including some rudimentary surgery), as well as lights to travel on jungle paths after dark and to see in camp. We have standardized on AA batteries to power a Stenlight and a PT Apex for the clinical work; and a couple of Streamlight Luxeon Polys and CMG Infinities for camp and other illumination. Because we have to fly or walk into the villages we will be serving, weight is a serious consideration.

I have reviewed the fabulous charts put up by SilverFox, but I would greatly appreciate some confirmation that I have actually understood the data he has so generously offered.

I conclude from SilverFox's data that AA Lithiums and NIMH batts are the most powerful form of storage capacity (i.e., both are similar in offering 2x to almost 3x the number of watt-hours over the alkies.) Is this correct?

Beyond that, if cost is no issue, the lithiums appear to be very much lighter than the NIMH batts, tho the latter could be brought home and used again if the extra ounces could be dragged around with us.

I welcome (!) any comments or corrections in my understanding of the available data.

Many thanks, John

 

[MrAl]

Hi John,

Yes Li-ion cells have a good charge to weight ratio. Better than
the others. Lead acid are the heaviest.
I use Li-ion AA size but also the 18650 size, and both are good.

I dont know if solar charging would be an option for you, but if you
are going south this could be worth looking into.

LEDs are more efficient when they are run at half current (or less).
Leds run at half current will run longer than twice the time period
with the same battery and be slightly brighter than half of what
they are at full current.

Might also need a fan to keep heat down on the body down south,
like on the forehead.

Might want to keep theft in mind also, if any of the natives get
sticky fingers you could be out of light for a while.

 

[Norm]

Welcome to CPF Bendlite.
MrAl
I think he is talking about Lithium primaries not Li-ion.
Norm

 

[VidPro]

I conclude from SilverFox's data that AA Lithiums and NIMH batts are the most powerful form of storage capacity (i.e., both are similar in offering 2x to almost 3x the number of watt-hours over the alkies.) Is this correct?

Beyond that, if cost is no issue, the lithiums appear to be very much lighter than the NIMH batts
Many thanks, John

and you generally CAN make conclusions from silverfoxes data too

if money is no object, AND the devices will run lithium primary cells without overdriving, they would be the best bet for saving lives in a packing up to go on a trip, needing power for critical operations.

they can be WAY lighter, like 40%, and they put out thier power without sagging under High loads.

stuff that does not have a high load, like 1 SINGLE 5mm led running off 2 AA cells will work just FINE with alkalines.

now with all that said, dont buy some cheap crud off of e-bay, or some faux knockoff product, or things could be far worse. alkalines, ni-??? and lithiums can all be purchaced very cheaply from off brand or fake brands, and can potentially be more usless than a set of alkies from the drug store.

NI-mhy would have the advantage of replacing alkalines in 98% of every situation, wheras some devices will overdrive with lithium primaries.

a solar charger for ni-mhys could keep you fresh with them, BUT it has to sit where it can achieve full sun, which can mean full dissapearance in some areas.

rechargables of ANY sort, could start your day with a "full" cell for each day, as opposed to fiddling with the battery you used yesterday which may not continue through the day.

Ni-Cd And Ni-Mhy cells can potentially be very depleated just from sitting around (self discharge), which could be bad in the middle of a critical operation. the newer LSD (low self discharge) are less likly to be depleated from just Time. primary cells have a much longer shelf life for being parked.

if i was just doing a 1-2 month stint in another country, i would have Brand name lithiums in any device that will run them without ruining the device.
if it was for longer, in some other country, i would want ni-mhy and some way (or 2 ways) to charge them.

 

[half-watt]

I need some help sorting trough the massive amount of information available here. My wife and I are going into the jungle of South America on a two week medical mission. We will have no external source of electricity (no mains, no generator, etc.) to charge batteries during the two week period. We have to be as self-sufficient as possible.

We need (bright) lights to perform medical procedures (including some rudimentary surgery), as well as lights to travel on jungle paths after dark and to see in camp. We have standardized on AA batteries to power a Stenlight and a PT Apex for the clinical work; and a couple of Streamlight Luxeon Polys and CMG Infinities for camp and other illumination. Because we have to fly or walk into the villages we will be serving, weight is a serious consideration.

I have reviewed the fabulous charts put up by SilverFox, but I would greatly appreciate some confirmation that I have actually understood the data he has so generously offered.

I conclude from SilverFox's data that AA Lithiums and NIMH batts are the most powerful form of storage capacity (i.e., both are similar in offering 2x to almost 3x the number of watt-hours over the alkies.) Is this correct?

Beyond that, if cost is no issue, the lithiums appear to be very much lighter than the NIMH batts, tho the latter could be brought home and used again if the extra ounces could be dragged around with us.

I welcome (!) any comments or corrections in my understanding of the available data.

Many thanks, John

medical missions: good chance to practice the "physical diagnosis" skills not having a complete laboratory at hand to perform extensive bloodwork and radiology.



coming from a backpacking background myself, there IS only ONE choice a long distance backpacker (NOT a car camper or weekend warrior type) who is away from resupply for 7+ days would make IF COST WERE NO OBJECT.

Energizer e2 Primary Lithium AA batteries.

upsides:

lighter than other choices.

more stored energy than most other choices.

excellent characteristic discharge curve which works fantastic in regulated lights like the Apex - extending their time in regulation by up to a factor of 4x.

excellent cold weather performance - not an issue in the jungle low lands, but if there are mountains where you are, perhaps some colder temps will be encountered.



more expensive (the only downside)


since COST of batteries is probably not an issue for a medical missions trip (other items cost orders of magnitude more) and will undoubtedly be an extremely small percentage (less than 1% no doubt) of the total cost of the mission, go with Lithium Primary (NOT secondary/rechargeable) batteries. Just pack your expended cells out of the jungle - common sense, right?! LNT - "leave no trace" is the backpacker's mantra.


this is really a no brainer decision (ignoring COST) for anyone with a long distance backpacking background. your situation is closer to backpacking than it is to a LEO, or a hobbyist/aficionado of all-things-lighting.


do yourself a favor, go with the Energizer e2 Lithium Primary batteries.

you can actually find them for about $1 apiece on the WWW. i just recently purchased 20 e2 cells for $19.95 (can't remember if i had to pay for shipping).

enjoy your mission, accomplish some good, and keep safe. best wishes and my prayers to y'all.

 

[eebowler]

John, you are very right about lithium AA cells and as half-witt said, go for a trusted brand (energizer) rather than trust an unknown.

Information you didn't ask for:

With respect to the Streamlight ProPolymers, they have lots of throw (can see far with it) and in my opinion, arn't good for general use in your situation. In a very short time in quality dark, you'll realize that for general tasks and for even walking, you DO NOT need loads of light. Your headlamps (if used for purposes other than surgery,) will see lots of use on their lowest settings.

Your CMG infinities would also get lots of use especially since they are small and SHOULD be carried with you at all times incase your main light fails or you get seperated from your tent for some unforseen reason. I'd suggest you upgrade to the New Gerber Ultra Infinities which produce more than twice the light output at the same efficiency as the original CMGs. The newest versions (many months now) use the newest LEDs from Nichia and approach twice the brightness of the older ones (which I believe was reviewed above.)

Instead of one ProPolymer, take a look at the Fenix L2D flahlight. As one of the value for money conscious flashaholics here, I think the L2D is a wonderful light and since it uses the new Cree LED, it's almost twice as efficient as what you already have (provided that you didn't mod them already ).

BTW John: WELCOME TO OUR MADNESS! (I'm sure you've been here a LONG time though.)

 

[half-watt]

Your CMG infinities would also get lots of use especially since they are small and SHOULD be carried with you at all times incase your main light fails or you get seperated from your tent for some unforseen reason. I'd suggest you upgrade to the New Gerber Ultra Infinities which produce more than twice the light output at the same efficiency as the original CMGs. The newest versions (many months now) use the newest LEDs from Nichia and approach twice the brightness of the older ones (which I believe was reviewed above.)

Instead of one ProPolymer, take a look at the Fenix L2D

eebowler ("bowler" from Cricket, i assume?? - T&T = great place to live i would imagine except for the longer days/daylight hours. less need for a flashlight?).

well, "ee", some real good advice in your Post.

let me ask you this, what do you think about extending your L2D-CE advice to having the L1D-CE replace the CMD Infinity Ultra?

Why do i ask/suggest this?

according to the fine FLR review that you linked to, the 50% burntime mark for the single 5mm LED in the InifinityUltra is 10:48 on an alkaline cell (longer on Lithium Primaries).

take a look at the same website's review of the L1D-CE, just shy of 20 hrs on LOW which is nearly 4x brighter OVERALL than the InfinityUltra!!! And, nearly 10x the throw (Cree v. 1x5mm at work here). Plus, ~30h on Lithium Primaries!!

Again, even to replace existing InfinityUltra's with L1D-CE's is probably a very small percentage (less than 1%???) of the overall mission budget.

Plus the L1D-CE could function in other capacities than just task lighting which the Infinities are pretty much limited to and perhaps maybe some simple walking of a flat path.

if really, really long burntimes with low levels of light output are desired (like to affect dark adaptation as little as possible), then (even though it's a different battery - one batt each and maybe one spare each - though the spare is optional), then i would suggest a 9V "transistor" battery powerd Pak-Lite. Small, light. Choices = two white LEDs (LOW output mode is very low) with GITD capability, or, the "Pilot" version with one RED LED and one WHITE LED. Mfr. claimed burntime for the higher powered (but still very dim LOW mode) "Pak-Lite Super" is SIX-HUNDRED HOURS (1,200 hours Mfr. claimed on Primary Lithium 9V)!!! The light output of the original (half-as-bright as the newer "Super" version) Pak-Lite is comparable to the InfinityUltra according to the FLR review.

the Pak-Lites provide a flood output. if more throw and shorter burntimes are 'ok', then the 9V powerd PALight might be a choice as it uses a plano-convex lens to focus the light into a spot, so no flood pattern.

Just a thought or two. Only my opinion and YMMV.

So, do you agree with this assessment, or have i totally missed the boat, so to speak?

Interested in knowing your thoughts. Please advise.

Many thanks,
half-watt (or half-wit if you prefer - 'specially if i'm missing the point here).

 

[eebowler]

Heck, you are VERY right! Good freaking point there half-watt! :bow:

 

[half-watt]

Heck, you are VERY right! Good freaking point there half-watt! :bow:

"ee", many thanks for the swift reply. and, oh,...genuflecting is optional and not a requirement - i'd save such for the Gurus on this site (SF, and a crew of others).

figures that "ee" (double-E??? e*e??? e^e??? e^2???) would agree with the e^2 (aka e2) choice for batteries!!!

take care, and have a great day there, ee.

 

[bendlite]

half-watt
You indicated that you had ordered 20 e2 lithium cells for 19.95. Where did you find this offer?

Thanks, John

 

[half-watt]

half-watt
You indicated that you had ordered 20 e2 lithium cells for 19.95. Where did you find this offer?

Thanks, John

John, Please see my reply to your PM.

 

[David_Campen]

half-watt
You indicated that you had ordered 20 e2 lithium cells for 19.95. Where did you find this offer?

I would be very suspicious of AA Lithium batteries from ebay, especially at that price.

If you want AA Lithium batteries of questionable quality then I have 20 or 30 lbs of Lithium AA batteries from the Excess Solutions sale of a year and a half ago. They are not reliable enough for me to use for backpacking or caving. I use a few in wall clocks and such - perhaps I should sell the rest on ebay.

The best price on Energizer AA Lithium batteries from a well known vendor is at Sam's Club - about $1.50 each in packages.

 

[ltiu]

Watch out for "some" eBay.com and Amazon.com Lithiums, some are old stock and set to expire in less than 3 years (in storage and unsold for 12 years). Check the expiration before buying. The packaging will give you a clue, older Energizer Lithiums have red jacket artwork.

Walmart, Lowes and Sports Academy all have decent prices on Energizer e2 Lithiums. Walmart's 8 pack costs about $16.48. Lowe's 8 pack costs about $17.98, Sports Academy's 4 pack costs about $8.99. All have year 2021 or 2022 expiry dates.

 

[David_Campen]

Watch out for "some" eBay.com and Amazon.com Lithiums, some are old stock and set to expire in less than 3 years (in storage and unsold for 12 years). Check the expiration before buying. The packaging will give you a clue, older Energizer Lithiums have red jacket artwork.

The batteries from Excess Solutions had expiration dates equal to those found in retail stores. Still, they were "used". My guess is that they had come out of some devices used by a hospital or in some other life safety application where they were changed out regularly whether used or not.

One person here who sells flashlights here and perhaps on ebay was reselling these for a buck each.