Olight I3s-CU and 10440

So I'm aware that Olight recommends against 10440 in the I3s-CU.

That said, has anyone been using this regularly for a keychain light?

Aware it will get hot, so does the UltraTac K18 SS which officially does support 10440.

It's about my perfect keychain light if not for no 10440 support. Rarely use a key light for more than a few minutes anyway, which is the only usable high/turbo duration on the K18 with a 10440 before it becomes too hot to touch anyway.

Yes, I've been using Efest 10440s in both an Olight i3s and i3e, for about 9 months. I keep the i3s on my keychain and use it almost daily. Yes it gets hot on high, but is fine for 20-30 seconds or so, which is all I usually need. Medium is hot also, but low is just warm and can be used for longer durations.

The biggest risk is not damaging the lights, if used on high or medium only briefly, but in over discharging the batteries. I inadvertently drained one down to under 2 volts without realizing it. Now I switch them out every month or so, or whenever I notice slightly dimmer performance.

Great lights, I hope you have the same luck as me so far.

Thanks. Yeah I've been trying it with Efest 350mAh IMR 10440 flat top for a few days.

Crazy bright, but does heat up faster than the SS Ultratac K18, enough so to make it of questionable use even for short durations. I'm just tired of the Ultratac lockout thing, having to always triple press the switch. I think twisty is a fine UI mechanism for AAA keylights, as long as it's smooth and flicker-free. And the i3s "CU" (CU? Hehe sort of like the Thrunite 'Ti' series, wtf) is just such a nicely built light, with such a nice big emitter for a 1xAAA. I hope Olight considers 10440 support for a next revision. I wonder what it would take to mod it, just a different driver?

dmsoule said:

Yes, I've been using Efest 10440s in both an Olight i3s and i3e
...
The biggest risk is ... in over discharging the batteries. I inadvertently drained one down to under 2 volts without realizing it. Now I switch them out ... whenever I notice slightly dimmer performance.

Click to expand...

I have no LiIon experience, so this is just a chance for me to learn more
1. Since the light does not have built in protection, to prevent over discharge and the risk of overheating during charging after that (did you have to dispose of the battery, or does it still work?}, could you use a protected battery instead?
2. when you notice slightly dimmer performance, what is the voltage of the battery?
3. what advantage does the LiIon have over Eneloop, for the way, and at the brightness, that you use your light. If you just are using LiIon on Low, can't you just use Eneloop on Medium and get about the same light (i3s)
4. If you use LiIon in the single mode i3e, what is that useful for, doesn't it just get dangerously hot?

If you over-discharge the 10440, I'm pretty sure that you must dispose of it or there is a SIGNIFICANT risk when charging... there may be a safe way to charge it, but I don't know of it and still wouldn't risk it.

You could use a protected battery... but I don't know if there is a 10440 that will physically fit in the I3S.

I use a 10440 in my I3E Silver just because it's amazing... I only use it for showing off really when someone else thinks his new AAA is soooo bright... I EDC an I3E with Eneloop on my keychain.


Lastly, I do NOT recommend using unprotected li-ion cells in lights without built-in protection for anything but "just for fun" very rarely used lights... unless you plan to be very very diligent about checking voltages.

I will have to look up my old post, because I am not sure what model, as there are many Olight AAA. I used 350 mAh 10440 Efest cells in it and smoked my driver I believe on the second run, I am only saying driver because I still got about 0.5 lumens out of it afterwards and another more informed member told me it was probably the driver that went poof.

joelbnyc said:

So I'm aware that Olight recommends against 10440 in the I3s-CU.

That said, has anyone been using this regularly for a keychain light?

Aware it will get hot, so does the UltraTac K18 SS which officially does support 10440.

It's about my perfect keychain light if not for no 10440 support. Rarely use a key light for more than a few minutes anyway, which is the only usable high/turbo duration on the K18 with a 10440 before it becomes too hot to touch anyway.

Click to expand...

I have both the i3s-CU and the K18SS. I have the K18 on my keychain and the i3S-CU sits on my night stand! I use the 20L setting for reading!

I have also used the 10440 in the i3S-CU. I tested it it for run time once. Only keeping it on for no more than 90 seconds because it did get hot! I was amazed at the output,,no doubt more than the ~400 lumens from the K18. My guess would be at least 500 and probably 550 to 600 lumens.

If it did support 10440 I would also have it on my key chain instead,,,even though it is heavier than the K18SS. I also have the K18 alum. sitting in its box!

I have the i3S in for testing and it does work with a 10440 no mention of it in the manual. The K18 does support that cell too also tested that. Voltages drop like a stone if you let it drain though it didn't blow up recharging. The voltage was so low it thought it was a Ni-MH at first until it jumped up a bit. I will ask Olight why it's not officially supported but it does work.
Honestly I only got the 10440 for testing I wouldn't use it normally for an AAA light