[Review] Olight i5T EOS - 300 lumens Single AA 2 modes flashlight.

Received a review sample of i5T EOS about a month ago, a light that continue the design line of i3T EOS (AAA) and M1T Raider (CR123A) but using AA battery as power source.

Let's look at a few FAQ...

  1. Does i5T EOS support 14500 LiIon battery?
    Officially, Olight does not support the use of rechargeable LiIon AA-size (14500) battery in i5T EOS as stated in the user manual:

    and the "available batteries" section mentioned above is:

  2. Can I use 14500 in i5T EOS even-though Olight says not to?
    Sure, but use it at your own risk and you will likely void the warranty of the light as it put i5T EOS in direct drive mode and it will draw close to the max current your 14500 battery can provide.

  3. What are the pros and cons of using 14500 in i5T EOS?
    - you will likely shorten the life of the i5T EOS due to excessive heat generated by and current going into the poor OSRAM P9 LED.
    - you will likely run into warranty issue.
    - you will lose the low mode and the ramping feature... actually you will also lose the high mode and go into a super overdrive super turbo mode.

    - you get an AA tacti-cool light that can do more than 1,000 lumens (I get ~1,600 lumens with a high drain IMR) at turned-ON.
    - you will join the secret list of an elite squad of brave souls who dare to do what others are not.
    - you get the bragging rights of "my light is brighter than yours".

  4. Can I use Olight 14500 battery in i5T EOS?
    Nope. The Olight 14500 model ORB-145P07 battery is too long to fit in i5T EOS. The tailcap will not close fully even if you manage to screw on the tailcap. The O-ring will be exposed and you are running the risk of crushing the i5T EOS circuit or the ORB-145P07 protection circuit.

  5. Can I get i5T in neutral white LED?
    Maybe. Olight generously distributed a special batch of i5T EOS neutral white version during their shot-show 2020 new light launch event while the normal version that you can get after the launch event is cool white. Olight is contemplating whether to release a neutral white version or not (I'm guessing from their history, the sales number for lights other than cool white command a low number). Here is hope that they do.

    Also, the blue accents along the double helix design at the i5T body was pitched as special version for a charity sale to help provide medical supplies to China to fight the coronavirus (COVID-19) outbreak. Here is also hope that Olight will maintain the blue accents design for the i5T EOS.

With the FAQ out of the way, let's get to the main review. Here is the specifications of Olight i5T EOS:

Olight i5T package:

It comes with a GMCELL Alkaline battery inside the light...

I'm really not a fan of having an alkaline battery being pre-installed in the light, this type of batteries are call alka-leaks for a reason. I wish Olight would stop doing this in their packaging. A lithium primary or NiMH would be a much welcome change.

Copper tailcap of i5T EOS...

Inserting battery by positive (battery nipple) side towards the head...

the head contact...

the TIR lens with OSRAM P9 LED...

a couple of close-up i5T EOS shots...

my measured output of Olight i5T EOS:

The usual disclaimer: I do not claim the above measured lumens as authoritative nor an indication of over/under-stating the number given by manufacturer. It's calibrated against some known light output (e.g. SureFire, Elzetta, etc.) so take it with a grain of salt and just as a relative reading.

and speaking of output, when tested with the following 14500 batteries:

I get these output...

Olight i5T EOS runs hot fast using that Nitecore IMR battery...

for comparisons, here is the regular standard 1.5V AA output vs 3.7V 14500 output:

and for an idea of just how bright Olight i5T EOS is when using 14500 battery, below is a video comparing it against Olight S2R Baton II:

where Olight i5T really shines is the runtime. what Olight quoted in the user manual:

but when using the included GMCELL Alkaline battery, I get the following:

I don't get the full 3 minutes of 300 lumens runtime with the included GMCELL Alkaline battery.

however, when using a better alkaline battery, this is what I get:

and getting a full 3 minutes of 300 lumens is no problem:

as such, continue the test with the following batteries:

and plotting the runtime against different batteries:

reveals that the fight is at the ~190 lumens output among different batteries.

In conclusion, I'm very happy with this Olight i5T EOS release and would wholeheartedly recommend this light to anyone who needs a small EDC light with easily available AA-size battery. I'll probably be getting half a dozen of these when Olight's production catch-up after their long break (they returned to work on 17th February 2020).

Excellent review. I carry this great little light daily.

Many thanks.

I have the Olight i3T EOS Copper, with Li-Po 3.2v battery’s in there.
It runs fine on the 3.2 instead of 3.5ish v.
As most of my AAA torches do.

I might order one of these i5’s and try it with th AA size Li-Po’s hey.

Where is the best place to order.
O’Light asking $44.

I love a little pocket rocket BUT that tail switch design looks like an
Accidental activation waiting to happen.
It really needs a recessed/flush design along the lines of
EagTac D25A. :frowning:

my results (150mm tube by ZozzV6 / adjusted using Maukka lights)

Olight i5T on steroids...

i did a quick test for you guys and used 14500 cell

eneloop: low 0.1A - 12 L
eneloop: High 1.85A - 256 L
SAFT primary: 0.25A - 115 L
nitecore 650mAh: 3.4A - 1060 L
SHOCKLI 660mAh: 4.4A - 1160 L
Keeppower 800mAh: 2.4A - 910 L
Vapecell 650mAh: 3.7A - 1050 L

Thanks for the review!

A 1xAA light that won't tailstand is a deal killer for me. Otherwise, looks like a fine pocket light.

If the tailcap was upgraded to enable the light to tailstand, there would be a i5T EOS in my pocket in a few days.


Nice graphs. What type of light meter did you use - and did you use Excel?

What’s with the tailstanding with baby torches.
Mine are usually in armpit. Pinkies, or between lips when using that size.

used my new toy to make a runtime....
(click for full res)

Mighty fine review.

… Just a few of my trusty Olight EOS CU lights with egg salad patina …

The copper version is waiting for my return to Miami, but I won’t be sportin’ li-ions, in it as a rule.


The copper version looks really sweet, now I regret not getting it when it was on sale for $29.99.

Does anyone encounter issues with 14500 in extended use? If I understand correctly this being a boost driver it goes into Direct drive when used with li-ion, so there is no temperature regulation or modes switching, just turbo all the time?

its turbo all the time
it will get (too) hot

and i have read some people complaining the cannot use 1.5V cells any more

For those still interested in the i5T copper there is a shop that will have them in stock next Monday: