Noob qn... best rechargeable for Olight

Banzai

Newly Enlightened
Joined
Jun 16, 2008
Messages
21
Location
Kota Kinabalu, Malaysia
Im waiting for my Olight T25 Tactical, T25 Regular & T15 lights.

I know that the T25 series uses 2xAA batteries and T15 uses a single AA.

Im considering getting rechargeable batteries for my above Olight collection but Im very new to rechargeables. Thus I seek advise/opinion on the best battery. At the moment, Im thinking of AW Li-Ion 14500 or Sanyo Eneloop AA.

My flashlight usage would be mostly using everynite/dawn for say 15-30 minutes interval daily at medium brightness setting.

Appreciate any comments...

FYI (from OlightWorld.com), Olight T25 series working voltage : 1.1V - 4.2V
for T15, the site does not state the working voltage... :confused:

Also, I am interested at Olight's T20 & T10 too (but have not place any order). Will getting AW Li-Ion 18560 to power the T20 be a good idea? (OlightWorld.com states that T20 is suitable for 2xCR123A or 2x4.2v batteries, working voltage: 3v - 8.4v.
For T10, compatible with single CR123A or 3v-4.2v RCR123A)

Anything (issues?) that I should know?

Thank you.
 

Banzai

Newly Enlightened
Joined
Jun 16, 2008
Messages
21
Location
Kota Kinabalu, Malaysia
THANKS ERIC !!! :thumbsup:

(sorry for my late reply. I was sick and am recovering)

Invaluable read for newbies like myself. If you dont mind, I wish to print out your Compatibility Chart. Id like to read when Im not online.

Another qn.
You recommended NiMH LSD for both T15 & T25.
For T15, any reason to choose NiMH LSD over Li-Ion ? (im trying to learn)

Also, for alkaline batteries, with regulated voltage flashlights eg Olight flashlights, will the output decrease gradually rather than the output graph stays at a certain volt for a certain time before the output suddenly drops?

Thanks
 

mdocod

Flashaholic
Joined
Nov 9, 2005
Messages
7,544
Location
COLORado spRINGs
good questions.

There's a few reasons I lean towards the LSD NIMH over the li-ion in this application but allow me to say that it's a very close toss-up between the 2 options and you can go with either.
1. You can buy 4 NIMH LSD cells for the cost of 1 good protected 14500.
2. The runtime on either will be very similar.
3. The li-ion will be about 12.5% brighter than a LSD NIMH, not really enough to notice but worth a mention. There are some 14500/AA compatible lights on the market that gain significant output with a 14500 and are designed to use the 14500 (jetbeam has one that really screams on a 14500, 225 emitter lumen on the li-ion, 130 on a regular AA, this would be enough of a difference for me to lean towards recommending the 14500 because it would be so darn cool to have a light that small pushing a cree that hard!).
4. Protection circuitry is another failure point and is one more thing that can "go wrong." When the LSD NIMH option for a flashlight works basically "just as good" as a li-ion option, I tend to lean towards the LSD recommendation for the combined factor that the NIMH chemistry is safer, and could be considered more reliable in some ways.

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On the subject of alkalines:

Little 1 cell pocket rockets have to pull a fairly significant amount of juice (current) from the battery in order to boost the voltage up to run the LED. Say it's pushing the LED at 1.5W (estimated), it would have to pull something like 1.7W from the cell in order to makeup for efficiency losses in the boost process, Alkaline cells may say 1.5V on the package, but in reality, under a load, they deliver much less, quickly falling to below the 1.2V that most NIMH can maintain above through the majority of the run. As the voltage drops, the circuit has to pull more and more current to continue pushing the same wattage. At 1.2V, it needs 1.4166 amps to get 1.5W to the LED. AA size Alkaline cells basically fall on their face at anything over about 0.75 amp, so you can pretty much bet on a high powered compact AA light having very poor runtime when used with alkaline cells. Alkaline just has too much internal resistance and will waste most of it's available power as heat within the cell. At high loads, NIMH cells outperform them in available capacity by leaps and bounds.

The circuitry will try it's best to keep the light running full brightness on any power source you give it within the accepted voltage range, but most of those circuits start to dim when the source power drops below about 1.1V, some can stay in regulation down to around 0.9V. Not sure about the Olight. So with an alkaline cell, you'll get some constant regulated output (short lived) and then it will be all down hill from there as that voltage drops down too low...

for comparisons sake, taken from SilverFoxes battery shootouts:
A sanyo eneloop at a 1 amp discharge delivers about 2.32 watt-hours capacity.
The top performing alkaline, a duracell ultra, at 1 amp discharge, came in at 1.27 watt-hours capacity. most brand came in at around 1 watt-hour or less. And in all of the tests, a substantial amount of that energy is delivered below 1.1V, which could mean a lot of diminishing output. I've seen output/runtime charts for a number of 1xAA powered lights, and on alkaline cells, they all wind up dropping below maximum output long before the cell is used up.

Now, if you use the light in lower output modes, alkaline cells will perform better and be able to maintain those lighter loads "reasonably" well. Alternatively, the T25, with 2 cells, would only have to draw about 0.7A to drive the LED at that same hypothetical 1.5W, the amount of useful power available from the cells would rise substantially, making alkaline cells slightly more practical, and since even when the cells drop down to say, 0.9V, the combination of the 2 is till 1.8V, plenty to keep the light in regulation.

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Hope that clears a few things up :)

Eric
 
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