REVIEW: Olight I3S-CU . First Impression (Pics and runtime)

Received one week ago this little brass light: Olight I3S-CU Polished finish:

Olight I3S-CU Polished finish: (made of brass)
LED: XP-L Cool white
REFLECTOR: Orange peel
BATTERY: 1xAAA 0.9-2.0 V (NiMH, Alkaline, primay lithium).
DATE: February 2016

FROM: Olight I3S-CU

Packaging, perfect for carrying the flashlight, to give away or to store the flashlight. Includes one alkaline battery ( I am not a big fan and, I will use with high quality NiMH aaa) and a Manual user, but I miss one spare oring.

The light not change the size of his predecessor I3s aluminium version, but the weigh is increased for the new material:

Some Pics now for comparisson with other "3 Series"; ITP A3 Eos upgraded (XP-G R5), Olight I3 (XP-G R5) and Olight I3S (XPG-2):

Now Pic with a Maratac aaa copper Rev3, my first copper flashlight, I am not sure yet if I will be a fan of copper lights....(but I love this Maratac!)

and with other well known aaa flashlights:

Some pics for detail of design; tailstand is allowed, the threads have a good quality and run very soft. The clip is strong enough for this little size. head to head with the auminium version, only 2 small external aesthetic differences:

Battery and Interface:

Information from Olight says; 0.9-2.0V, and of course I will no try 10440 on this. I prefer NimH and Primary Lithium.

Is a Twisty light (tighten and loosen head for changing modes).

No memory modes, always turn on the highest mode. The sequence; High,Mid,Low,High,..... (this I3s-CU has not hidden strobe as the I3S aluminium version)


A XP-L Cool white welll centered in small Orange Peel reflector. Perfect beam, more flood than his colleague in aluminium:

A animated gif:

Information about modes and runtime in high:

Official information manual:

First I put a small graph of relative power modes in % to get an idea of which is the distribution of modes. Considering that the flashlight has 3 modes, but how high suffers a drop in power "step down" programmed for 3 minutes, I have included the value of this step as a reference within the graph;

(ceilling bounce)

Runtime test in High mode with a Panasonic Eneloop NiMH min. 750 mA. One data for minute, for reference the 100% on this test is the highest value between 30 and 180 seconds (ANSI NEMA FL-1 standard).

In detail the first 4 minutes of test, one data for each 10 seconds. The step down begins at 3 minutes, slowly descent for 30 seconds to about 45% of initial power and then the line is flat:

I love the light, my score is 9/10. (for the price is a perfect 1xaaa, but I will prefer a diferent order of modes, my preferred for aaa lights is low/mid/high).
This sample was not provided for review.


Thanks for another immaculate review, always a treat to read :slight_smile:

Well done review. Looking into one of these so the timing was perfect. Thanks

Nice review. Great pictures! Nice square threads.
I wish I had one, but in a way it is like gold plating a Ford car to polish something with such a simple conventional shape. I like the looks of Maratac best of those pictured, but even that is a shameful waste of the potential of a numerically controlled lathe.
The step down at 3 minutes demonstrates the regulation and might be useful, especially with lithium primaries. Alkalines ramp down all by themselves. Their voltage droops when current is drawn and recovers when they rest. So a circuit that droops with its input voltage might be just as useful as this deliberate regulation.

Thanks guys for comment.
I have bought the raw version, (not polished), perhaps is a preferable finish for some people, when it arrives I will include some Pics here for comparison.

Good review.

nice review!

Brass is so much harder then copper and aluminium, one wonders why there are not more flashlights being made from it.

Love the looks of your Maratac!


- I have tested again, after step down, I wait a few seconds, and cycle again to high mode. The light maintain again for 3 minutes the high mode, with a power over 90% of initial

Do copper or brass have any advantage transferring heat compared to aluminum? How would the three rank from best to worst?

I think the better transmission of heat is copper and the worst is SS, I am not sure what is the best between aluminium or brass, but really, for this aaa with NiMH, in the real use, I not perceive difference.

Yesterday receive the unit in fisnish not polished: “raw version”, I like both….
bought here in hkequipment

Some Pics for comparisson:

The manual says copper but you described it as brass.

nice collection.

It is brass, we take cu to be copper as that’s it’s chemical symbol, but the Chinese seem to use cu to describe brass - they did the same with the silver i3s and described it as cu, but it was brass too - so blame the Chinese lol

Great review :slight_smile:

Yes, both are brass. I sorry for use the chemical symbol Cu….but is the name of this light,… O:-)

The manual page you showed described it as copper with gold plating.

In china perhaps they use the word copper for describe sometimes the brass alloy.
I have read some descriptions of this in his web: “bronze body processed by PVD coating with titanium-gold coloration.” or ” It is made of high heat conductivity and low electrical resistivity brass alloy”…

But is brass, in his web says brass, in my review says brass in the first sentence… I think is clearly that it is made of brass….

The advantage brass, aside from appearance, is that it is easy to work with. A German told me it was invented for no other purpose than to be easy to machine, and it is the standard by which machining ease is measured. So there is a level of complexity and and precision at which brass becomes cheaper to make than aluminum, in spite of the cost of the copper content. It also can be soldered.
Copper conducts heat and electricity better than aluminum, by volume, but I think brass not as well. Those are conduct much better than steel or titanium.

Anyone try a lead test kit on the raw brass one to see whether any lead is detectable in the alloy? I don’t know if a negative result would be conclusive but it would be good to know if there is a positive result.

Anyone know of another light of this size with the same reflector and LED typ?