Mountain Rescue Help

rhinochopig · Jan 23, 2009

Hi Chaps,

I registered here to hopefully tap into your wealth of expertise. Please forgive any ignorance, as I'm purely a user of torches and have no knowledge of their electrickery.

I'm in a mountain rescue team, which means we are often out most of the night searching for people. I have a few related questions.

1. What are the best* cells available today in Sizes AAA, AA, D? *In that I mean balance of, highest mAH, self discharge, voltage drop off.

2. My current charger is a cheap uniross ultrafast charger (Charging current = AA 1000mA; AAA 400maH). Will this fully charge the 2700maH cells I currently use + any you may recommend.

3. What is the most suitable charger (if above is no good)

4. The perfect torch for mountain rescue has the following criteria: Uses standard cells (AA pref for commonality with GPS), is as bright as possible, has a very long burn time, is weatherproof, and as cheap as possible. Just out of curiosity, what would you chaps recommend against my criteria so I can pass on the advice to team members looking to change their torches?

5. Out of nothing but curiosity, why do rechargeable cells have a lower voltage than none rechargeable? Does this mean my LENSER will put out less light on rechargeable cells?

In case anyone is interested, I currently use a light & motion HID LION ULTRA (mountain bike light) which is superb (but was expensive), but obviously fails on the ease of battery replacement criteria (although I get about 5-6 hours out of the battery pack, team rules dictate I have to have a spare, so an LED LENSER proved cheaper).

The L&M is backed up with an LED LENSER P14 (bought last week, which isn't that great TBH - too focused when the beam is collomated, and not enough throw when set to flood - my terralux maglite is better but far too heavy).

I've also just replaced my old head torch with an LED LENSER H7 headtorch as it seems to be the only company that makes a decent LED robust head torch. Some of the team use these and they are impressive little things.

Thanks for the advice!

balou · Jan 23, 2009

1. I'd say 18650 Lithium Ion rechargeables. Li-ion have extremely small self discharge and voltage drop. They're only slightly bigger than an AA cell, have about the same capacity but triple the voltage - meaning 3 times total energy. But they are not a common size...
If you want to stay with more conventional batteries - two options:
Eneloop or generally low self discharge NiMH cells: As you might have guessed, lower self discharge

. Normal NiMH cells discharge quite fast. They're very good if you store your light for some time.
Else, good quality NiMH cells. Sanyo has 2700mAh cells (other companies advertise their cells as 2700mAh, but as far as I know, Sanyo is the only company that has true 2700mAh capacity). Disadvantage of them is the self discharge rate. They loose about 20-25% of their capacity per month (well, unless you recharge them again, no permanent loss).

2. Yes, it will charge your current cells, quick chargers have microprocessors in them which sense when the battery is full, they will charge any capacity NiMH or NiCd cell. But 'quick' is relative, they may take nearly 4 hours to charge. 2700mAh/1000mA = 2.7 hours, then the whole thing times 1.4, because 40% of the energy is lost while charging. (Edit: if it takes significant less than that to charge, then you probably need a new charger - that would mean it uses a fixed timer regardless of the actual battery capacity)
But charging too quick isn't a good idea anyway - it puts quite some stress on the batteries if the charging current is high (my charger has a fan to cool the batteries....)
For Li-Ion, you'd need a different charger

4. Define 'cheap'

. And do you need a lot of throw, or flood? How much runtime is required? How big can the light be?

5. Different chemistry. Look at wikipedia for more info, it has something to do with the electronegativity of different elements.
LED flashlights will generally not be dimmer if used with rechargeables. The brightness of LEDs varies with current, not with voltage. As a matter of fact, in many flashlights NiMH will make the flashlight brighter, because NiMHs are capable of delivering much higher currents than alkalines. Energizer Lithium primaries(non-rechargeable) are also capable of delivering high currents, but they're quit expensive.

edit: Ok saw that you posted some info below your 5 questions. Disregard the question about flood or throw above. But still.. cheap, long runtime and as bright as possible are 3 requirements which don't fit together well

yellow · Jan 23, 2009

1st off, I dont like Lenser, but I am not going to type why, NOW, nor will I comment on them NOW.
The only thing I do type is: the use of rechargeables is not allowed with them

There is no headlamp NOW that would fit my perfect criteria,
but the Princeton Tech APEX seems to be the best overall, and it runs on AAs
(I dont like the brightness/runtime choices)

The AA of the whole team, exept for the urge given to use them for GPS, is a good choice, its a very nice cell.
Best were "precharged" ones, like the Sanyo Eneelop (but with a better charger than comes with them. A charger that charges each cell individually, no pairs!).
If You are able the charge the Ni-Mhs just be4 using them, the higher 2700-2800s have the edge, else the Eneloop-kind is better (generally the Eneloop is considered better, I have only such cells now)
2 AA models like the ones from Fenix or Jetbeam, or ..., are considered very good, but a light that houses 4 of them, gives a longer runtime (surprise?)

AAAs are crap

that typed, the best cell overall is a protected 18650 Li-Ion.
Nothing comes close!
When one has no lights for AAs and no good charger for them (and no need to use them for any other important gear), it is best and cheapest to go for the Li-Ion cell.

For a handheld light, that makes 2 hours full (datasheet granted) output for a single cell,
so You guys might be better off with a 2 celled light?
If You ask me, and thinking of size, brightness and runtime of the P14 You use now, one of the JETBEAM Jet III (= single 18650) models would be good for Your team. Cheaper than the Lenser, the levels can be programmed for brightness/runtime as each of You like, comparable build quality, robust, ...
They do not feature a focusing beam - imho a focusing beam is just for to fight a bad beam - but I have no use for throw & am a reflector guy.

Jetbeam has a model with one of the new Quad-emitter led in the make, the MX-1.
Will be butally bright, but You buy brightness with reduced runtime, very easy.

Unfortunately there is no good headlamp atm for the Li-Ions.
I have a Streamlight Argo HP modded to an actual led and the battery compartment to house an 18650. Simply great...
... such things should be in the make, imho.

Toaster · Jan 23, 2009

1. Sanyo Eneloop AAs

2. Yes. But I'd be more worried about it overcharging cells.

3. Maha MH-C9000 is generally considered the best charger for AAs.

4. I would keep an eye out for Fenix TK40 that was revealed at SHOT. 730 lumens, uses 8xAAs, available in March for $150. See this thread for additional info.

5. Different chemistry than primary cells

Hooked on Fenix · Jan 23, 2009

rhinochopig said:
4. The perfect torch for mountain rescue has the following criteria: Uses standard cells (AA pref for commonality with GPS), is as bright as possible, has a very long burn time, is weatherproof, and as cheap as possible. Just out of curiosity, what would you chaps recommend against my criteria so I can pass on the advice to team members looking to change their torches?

5. Out of nothing but curiosity, why do rechargeable cells have a lower voltage than none rechargeable? Does this mean my LENSER will put out less light on rechargeable cells?

Sorry, but as bright as possible, long burn time, and as cheap as possible don't really go together. You can have one or two at most. Long burntime and as cheap as possible gets you a dim light. You can have bright as possible and long burntime only if it's a light with multiple brightness levels and that makes it cost more. I'd suggest a Fenix L2D Q5 or LD20. These lights put out 180 lumens on 2AAs which is about the best you can get from AAs currently. They have four brightness levels so you can maximize runtime by using just the amount of light you need at the time. They are waterproof, well built, and among the best you can get. These lights go for around $60 and are for the most part only available online.

As for the question about rechargeables, alkaline batteries always list their starting voltage of 1.5 volts which almost instantly drops under load. Rechargeables list their average voltage for a charge. While rechargebles start out at a slightly lower voltage, they maintain a higher voltage longer than alkalines which makes them work longer than alkalines in high drain devices. Your standard NiMH battery has a starting voltage around 1.42 or 1.43 volts. With an Eneloop, it's more like 1.48 volts. Eneloops are the only rechargeable battery that really works in cold weather. The highest capacity batteries have a high failure rate as they develop a high discharge rate and become useless. If your light isn't regulated, it may start off dimmer with rechargeables. If it is regulated like the lights I suggested are, there will be no difference in brightness between rechargeables and alkalines.

HKJ · Jan 23, 2009

1) It depends on how long time there is between you charge your cells and you use them, if that time is less than a month any 2700mAh+ from a quality brand will be ok. If you have to store you cells for a few months between usage, get eneloop for AA and AAA cells, they have lower mAh, but they will not do any self discharge (It takes a few years before they have discharged themself).

2) A 1A charge current is fine for AA cells. I do not know the Uniross charger, but it will probably be ok.

3) My favorit advance charger is a MAHA Powerex MH-C9000 charger, but your do not need that kind of charger for normal use. When I just need to fill my batteries I uses a Ansmann energy 16, it takes 12 AA at a time. The charges to stay away from are the fast charges (below 1 hour charge time), the slow charges (above 10 hour charge time) and charges that requires two or four batteries at a time (the charger must be able to handle one battery at a time).

4) For AA cells I would recommend the Fenix TK20, it is a very niece flashlight. If you want to try some other cells (18650), the Lumapower MVP is a nice light.

5) Rechargeable cells do NOT have a lower voltage. Alkaline starts at 1.5 volt and drops very fast in voltage (depending on load) and are assumed empty at 0.9 volt, rechargeables stays at 1.2 volt, nearly independ on load. They start at 1.4 to 1.5 volt, but do not really get below 1.2 volt before they are empty even with a high load.
One comparison is to take a Fenix L0D and compare a NiMH and a Alkaline cell, when running the light at high. The Alkaline is supposed to have most energy, but due to the high load the NiMH wins with a factor 3 in runtime, the Alkaline can simply not keep the voltage high enough.

There are many nice light, one of the best ways to see how they stand up to each other is to look for "Selfbuilds" tests.

deranged_coder · Jan 23, 2009

How cold does it get out there at night? Is there any concern with batteries failing due to extreme cold? I know that lithium primary cells are usually recommended if extreme cold is a concern since they have a fairly broad operating temperature range. Not sure how NiMH or Li-Ion compares to lithium primaries, though. :shrug:

asdalton · Jan 23, 2009

I'll second the recommendation for the Fenix TK20 with AA Eneloops or similar low self-discharge NiMH cells.

With the TK20 you have:
- smooth reflector for good throw and spill at the same time
- warm tint bin, which often improves visibility of outdoor objects
- low mode option to extend battery life
- ability to use Energizer lithium AA cells

StarHalo · Jan 23, 2009

I would recommend against any rechargeable cell in a mountain cold environment. Most rechargeables are rated down to -20F, but they start getting iffy once you go below 0F, plus li-ions can be irreversibly damaged by cold. Stick with primary-only, Energizer ("Ultimate") Lithiums in the AA format, or any of the name-brand 123s.

For an emergency/mission-critical light, AA is indeed the way to go due to interchangeability. I would recommend a 2xAA format for better runtime and brightness, which leaves you with plenty of options; The Fenix LD20 and TK20, Nitecore D20, JetBeam Jet I Pro EX, to name a few. My personal vote would be for the JetBeam, as its infinitely variable interface allows for any output between 2-200 lumens, plus it includes a whole range of strobes, locators, and SOS modes should you need them (see it here:http://www.bugoutgearusa.com/jetiproexv2.html). But any of our modern flashaholic-grade lights will be unchallenged by the daily use and abuse of a mountain environment.

One other note; when you're in the cold, you should store/holster your flashlight close to your body so it can remain warm and ready for use. An interior coat pocket or the like works fine for this. Once you're actually using the light, the heat from the emitter will keep the light warm and operating normally, even if you should lose it in a snowbank for an extended time. You might also consider leaving the light on an ultra-low locator mode (as found on the JetBeam) for the entirety of your rescue mission when the light is not in use, so that should it get dropped/lost, you have a much better chance of finding it, even in the aforementioned snowbank.

Cydonia · Jan 23, 2009

rhinochopig said:
4. The perfect torch for mountain rescue has the following criteria: Uses standard cells (AA pref for commonality with GPS), is as bright as possible, has a very long burn time, is weatherproof, and as cheap as possible. Just out of curiosity, what would you chaps recommend against my criteria so I can pass on the advice to team members looking to change their torches?

Bright as possible, very long run time, weatherproof...and cheap? :laughing:

Fenix TK20 with AA Sanyo NiMh "Eneloops" Low Self Discharge cells will be your best bet.
The charger you have now should be fine with Eneloops. Charging them at 1000ma or 0.5C is fine.
It's the charge termination detection/method of that particular charger that is something one should look into and understand though.
It may or may not be ideal :shrug:

Gunner12 · Jan 23, 2009

1. Not sure, I don't have that much battery knowledge. More experience people will and have already chimed in.

2. 1000 mA charge current should be fine with the current AA batteries that are 2000-2700 mAh. AAAs aren't that good except for back up lights. Avoid 3AAA lights if possible. Almost guaranteed direct drive which means constanly dimming and also because 3AAAs have the same energy capacity as 1 AA battery.

3. Not sure.

4. Standard cells, Cheap, Bright, Long running, weather proof(and tough?), pick three. A light with all three is ususally not AA powered and something I wouldn't depend on for rescue squads. I'd place minimal cost at $40-50. State a price range, how far you want the light top throw, runtime prefered, multimode or not(low mode, high mode, strobe etc.), and size and we'll see what we can find.

5. The voltage depends on the current being drawn from the battery. For example in your Lenser(ignore the runtime, it's probably till you can't see the LED glowing) you will get at least the same output and more + flatter runtime(no drive so still not regulated) because alkaline batteries sag in voltage at the current it draws. Recahrgeable batteries can take much more voltage before sagging and keep their capacity better at higher currents then alkaline batteries. LedLenser seem to take into account the internal resistance of alkaline batteries so they put the LED on a relatively small pedistol and that hinders some of the heatsinking which mean the current rechargeable batteries can supply might cause the LED to overheat. It seems to be fine with recahrgeables though since people here have used it with rechargeable batteries without problem.

Headlamps, I'm not that sure about but if you want a floody headlamp look at Zebralights.

For the lights, look at the Fenix brand, Olight, Jetbeam, Nitecore maybe, and a few others that people will probably post.

:welcome:

Scourie · Jan 23, 2009

4. Another vote for the Fenix TK20 and Energizer L91 batteries. Review here;

http://www.light-reviews.com/fenix_tk20/index.html

Rob

rhinochopig · Jan 24, 2009

Thanks Chaps,

Some good advice there. So in summary, eneloop cells, check out fenix torches, and my charger is probably ok.

A couple of other questions, if I may?

Has anyone tried tried one of the terralux three LEd conversions for the maglite, and what sort of run times do you get with your set up - the reason I ask, quite a few members have maglites.

Why can't LENSER torches use rechargeables?

Kind Regards.

StarHalo · Jan 24, 2009

rhinochopig said:
Has anyone tried tried one of the terralux three LEd conversions for the maglite, and what sort of run times do you get with your set up

I own a TerraLUX TLE-300 Mag; it's mostly about how much raw output you can get from an LED drop-in for the least money. It's serious bang-for-the-buck at 600 lumens for $70, but you're not going to get much runtime - probably 1-2 hours in the 2-4D cell configs. Mine is a 2D powered by 6AA cells, I'd estimate about an hour total runtime.

My TLE-300 mini-review that I've posted elsewhere:

StarHalo said:
It's essentially just three LEDs, each with its own optic, all in a self-contained drop-in puck with all the necessary circuitry. It's a minimal difficulty install, you remove the stock Mag reflector and bulb, put the TLE-300 in the socket, done.

Optic lenses mean *serious throw* and the TLE-300 doesn't disappoint, projecting a big fat hotspot with no corona or spill to speak of. You lose the Mag's focusing ability, but when you've got a glaring hotspot that's over two feet across from only ten feet away, you don't need it. The only con is that the hotspot looks a bit like a round, multi-pointed star (the optics to some degree project the square shape of the LEDs) but in normal use, especially outdoors, you don't notice it.

The TLE-300 is my fave Mag drop-in based on its ease of install, use of standard batteries, and good old "damn that's bright"-ness. I've always liked the idea of an LED hotwire/ROP that doesn't require any modding, and this certainly fills the bill.

My 2D TLE-300 Mag:

In short, it's an awesome idea if you want an insane-output LED Mag on a budget, but I'm not sure that it'd have much practical emergency use. For that I'd look to a single-emitter drop-in for more practical output and runtime, preferably the very solidly built and performing Malkoff units (http://www.malkoffdevices.com/shop2/index-main_page-index-cPath-1_2.html)

Gunner12 · Jan 24, 2009

The main problem for the drop-in seems to be the oddly shaped beam. Not sure how that will affect your decision.

crazyk4952 · Jan 24, 2009

As far as chargers go, the Maha Powerex MH-801D is a really good charger It will charge 8 AA batteries at a 2000 mA or 1000 mA rate.

http://www.mahaenergy.com/store/viewItem.asp?idProduct=407

For batteries, may people have mentioned the Eneloops, which are very good batteries. However, If you will be using the batteries within a month or two of charging, you will actually get more runtime from something like the Maha powerex 2700 mAH OR Sanyo 2700 mAH batteries. Yes, these batteries have a higher self discharge than the eneloops, but they also have a higher capacity. Eneloops have a capacity of about 2100 mAH. If you search the CPF, you can find that other people have posted self discharge comparisons of these batteries and have found that the Powerex 2700 had more energy left after 60 days than the eneloops.

Just my 2 cents...

Lighthouse one · Jan 24, 2009

You might want to look at the Eagletac P10A2. It is the brightest 2 AA light available at this time. It has 2 levels- so you can use the 60 lumen low and save the high for when you really need it. Good quality light.

https://www.eagletac-store.com/product_info.php?cPath=103&products_id=607

Hooked on Fenix · Jan 25, 2009

crazyk4952 said:
As far as chargers go, the Maha Powerex MH-801D is a really good charger It will charge 8 AA batteries at a 2000 mA or 1000 mA rate.

http://www.mahaenergy.com/store/viewItem.asp?idProduct=407

For batteries, may people have mentioned the Eneloops, which are very good batteries. However, If you will be using the batteries within a month or two of charging, you will actually get more runtime from something like the Maha powerex 2700 mAH OR Sanyo 2700 mAH batteries. Yes, these batteries have a higher self discharge than the eneloops, but they also have a higher capacity. Eneloops have a capacity of about 2100 mAH. If you search the CPF, you can find that other people have posted self discharge comparisons of these batteries and have found that the Powerex 2700 had more energy left after 60 days than the eneloops.

Just my 2 cents...

It's not the shelf life I'm worried about for the batteries. It's the cold weather performance. I've tried high capacity cells in the cold. They don't work. I've used Eneloops in the teens and 20s F and they never failed once (not even on a 3 day backpacking trip into the Sierra Nevadas in November). The OP is into mountain rescue. It gets cold in the mountains, especially now in winter. 2700 mAh NiMH AAs won't work well for this application. In the cold, there's only two kinds of batteries I'd trust: Eneloops and lithiums.

carrot · Jan 25, 2009

I dunno, but I'm thinking if you want the AA formfactor some NiMH or lithium AA's in the upcoming Fenix TK40 would be a good choice.

rockz4532 · Jan 25, 2009

carrot said:
I dunno, but I'm thinking if you want the AA formfactor some NiMH or lithium AA's in the upcoming Fenix TK40 would be a good choice.

+1, the TK40 should suit your needs, long runtime on the low modes, batteries might be a little tricky though

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