What are the smallest, good quality PROECTED 18650's?

I use these in my TK-75 http://www.fasttech.com/products/0/10001980/1315402-panasonic-ncr18650a-18650-3100mah-37v-protected-re

Well, look at my above link, the keeppowers are longer…not shorter.
Please don’t give advice if you aren’t 100% sure, I’d rather wait longer for good / correct advice (no offence intended)

That doesn’t help, different torch and different carrier.

Don’t get so upset, all the advice I gave about the batteries is correct, I don’t care what it said in your link, I have all the batteries I mentioned, did you read my post?

I’m not upset.

You said I should use unprotected cells because the K40 carrier runs them in series!!! If I’d followed your advice I would have wasted my money!

Link here for an Australian ebay seller. He has the battery lengths listed. I think there is a mobile number you can ring him on if you wanted to confirm battery length.


Yes, I’ve purchased from him before, I texted him a few times today, he has no batteries under 69.6mm.
No KP’s or ET’s.

So these aren't 68.8 +- .05mm?


BG has KP delivered to Aus for AU$38.XX (4 of), they measure according to BG at 68.9mm…

According to your ebay link, KP use several manufacturers of cell, so it seems quite likely various lengths of the same apparent battery are possible. And if by NCRB you mean the Panasonic NCR18650B (3400) then they too might not be what you think. Mine are over 70mm, nearer to 72 IIRC.

Edit: Ive not measured, with calipers (mine are metal, I dont want sparky sparky), but a tape shows very close to 70 anyway. I recall it being said they were over 70. Might be wrong on that.

I don’t believe so, I put one of them next to my lime Panny and they looked identical

And what is the problem with these? They are the shortes protected i know of. Can u show us your “problematic” carrier?

They may work, if they are in fact 68.5mm.
I’d take a few macro shots but the missus has the camera OS at the moment.
I believe the problem may be a solder blob being too big and stopping full compression of the spring, so the shorter the better.

IS can do 3 of the 3400mAh ET’s for $45USD, they are a bit more expensive and a bit shorter.


EagleTac 3400mAh Protected Li-ion 18650
$19 each free shipping

Anyone know who is cheaper?

“Measures only 68mm in height (+/-0.1mm) and 18.5mm in width ”

Nice find, but…We’re sorry. This item can’t be shipped to your selected destination. You may either change the shipping address or delete the item from your order.

How about this cell?

Just a hair over 68mm. Panasonic cell inside too.

One of the pictures shows the cell standing side-by-side with my NCR18650A protected and it’s really shorter.

Yep, I was considering these ones:

Tiny bit longer than the ET’s but half the price

I am actually surprised your NCRs are ‘forced’ into your K40’s carrier as I used to own a stock Supbeam K40 and lately the Deft X, and both lights took in my NCR-As from Fasttech (70mm) without a hitch.

Perhaps Supbeam shortened the carrier in the later batches?

Perhaps when Vinh did the mods to the carrier a blob of solder is too big and not allowing the spring to fully compress.
I am communications with him about this. I can fit any of the Blazar, NCRA’s or NCRB’s in that carrier no sweat.

For all of the hassle of having to find and bring in short expensive batteries is modifying the carrier an option at all?

I don't have your exact light but my Blazar cells fit snugly in the carriers for my BTU shocker, my TN31 and a Spark headlamp 4-pack.

I know it probably isn't your first choice but is there any way that you could perhas take a bit off the spring or at the positive end?

Seems like that would be a better long-term solution than spending so much time and effort searching for short batteries to fit.

As an update for everyone that has helped or commented here, Vinh thinks there is a problem with the carrier as his 70mm KP’s fit in his no problems.

He is modding and sending me out a new carrier after checking before he sends that his 70mm cells fit.

Anyone considering buying one of Vinh’s modded monsters should pull the trigger, the way he looks after his customers is admirable.