I ordered 16 Samsung ICR18650-26F 2600mAh batteries from Banggood (used the BFL discount code).
(shipping took 33 days, dock worker strike (or slowdown?) on the USA coast, so that might be responsible for a a few weeks delay for arrival)
Have been running Charge Test (500mAh) on the batteries using my Opus BT-C3400 charger.
So far the batteries seem genuine, they all come with the exactly the same 3.80 volt charge from the factory and have a real capacity of 2600mAh.
I might end up ordering more of these.
Isn’t this about the same price as fasttech?
https://www.fasttech.com/products/1420/10002357/1170700
Though I bet it’d arrive a lot sooner.
Technically the Fasttech listed is a few cents cheaper.
But you can use the “BLF” coupon code at Banggood, to save about 30 cents a battery, off Banggood’s price.
“BLF” works at fasttech for 5% off batteries too 
Btw, I noticed that Panasonic 3400 mAh 18650 unprotected is $14.59 on flash deal right now, I was just about to get them from Fasttech for $15.24.
Fasttech also has BLF code, but fasttech has a poorer reputation in terms of battery shipping, although the situation may have changed now
Yeah, it took quite a while with my last battery order.
Ordered 9/20/2014
Delivered 12/23/2014
Banggood has free shipping via air mail but Fastech you need to pay $5-6 or choose super slow surface shipping.
I also think the BLF code on Banggood gets more discount 
The last time I tried (within the last 3 weeks), Fasttech web site did not accept any code at all. I tried 3 or 4 different ones.
Bit of an 18650 newbie so thanks for the tips, after getting the Ultrafire 18650 3.7V “3600mah” from BG and finding from by BT-C3100 that they were a ridiculously low 750mAh I was looking for decent batteries !
The Panasonic 18650B 3400mAH are quite a bit more expensive even with the special sale than the Samsung ICR18650-26F 2600mAh and according to some reviews on BG turn out between 2500 and 3200 so I’m not sure they’re a better deal?
The Banggood Samsungs are a really good deal, except for the long delivery time (expect around roughly 20 days).
Using the BLF coupon code at Banggood brings the price of those Samsungs to $4.15 each (in packs of 4).
Tested the Samsungs on my Opus C BT3400 charger, they seem to charge up to a little over 2600mAh capacity (like 2610, 2625, etc)
Thanks, at this point I probably only need two though so I might go with the Panasonics unless the Samsung’s can be had in a pack of two?
I’m going to order 6 panasonic from banggood.
Are you sure that NCR18650B are “quite a bit more expensive”?
How much did you pay for those Ultrafire cells? Lets say they were 2$/pice while NCRB protected are 8,3$/piece.
So that would be 0.0026$ per mAh for UltraFire cells or 0,0024$ per mAh for NCRB. UltraFire cells are actually more expencive than Panasonic cells.
For mentioned Samsung 2600mAh cells math would be 0,0018$ per mAh…
No, you will not 
Just do some searching, they can be bought single as well.
If you set the C-BT3100 to Discharge/test at 200mAh with the Ultrafires, you might get the capacity above 750mAh.
That’s a thought, just started the test. I knew something was wrong from the get-go as they are extremely light. It’s really shameful that BG would sell 750mAh labeled at 3600mAh! This has to be the most outrageous claim I’ve ever seen, beats MPG ratings and wattage of LED lights
With two Samsungs/2600 at $10 and two Panasonics/3400 at $14 I think I’ll go with the Pannys.
don’t forget to check my deals thread!
sometimes I get codes for batteries also
i asked for this ones…
I looked em up on the link, saw the price, checked with HKJ (he said they are very good cells) promptly bought 8 of em.
They’ll do over 5A and HKJ showed they’ll even do 7A. At 2600mAh, that works for me for a lot of lights.
i use 4 of those samsung batteries in my SRK (-clone), and they work fine as far as i can tell.
both the samsungs from BG and the protected panasonic 3400 i have are quite long batteries though, so they won’t fit in every flashlight or charger i have.
Yea, it takes a little more work to screw on the top of my Sky Ray Kings when I have the Samsungs in them.