So, being new to the whole 18650 thing i need some help choosing a battery for the Convoy S2 i will be getting.
I would like to go with protected cells and id like to get good runtime. Are there any issues with certain batteries not fitting this light? what should i look at, what should i stay away from? I am planning on getting the nitecore intellicharger as i have heard good things about it.
thanks
Adam
In my experience, the S2 can generally fit any size 18650 cell, protected or unprotected.
Anything you particularly recommend in terms of protected cells?
Admitting that there is a slight conflict of interest here 
, but I really like the protected Panasonic PF cell. The protected Panasonic NCR18650B is also very popular. There are a few quality manufacturers, such as KeepPower, Orbtronic, etc. In my opinion, if you are going to get a protected cell, you might as well get one with a high-quality circuit.
He means these .
http://www.mtnelectronics.com/opencart/index.php?route=product/product&path=59&product_id=50
fixed it for ya
What are the main differences between the PF and B cells?
I think the main difference is the capacity but you should check out the comparator by HKJ. Battery test-review 18650 comparator
Compare the Panasonic 3400 (NCR18650B) with the Keeppower or Obrtronic 2900 (Using NCR18650PF).
Capacity, PF is 2900mAh and B is 3400mAh and that B is protected, PF is not. I think you will be very happy with B.
I use PF´s in my e-cig (and generally i use unprotected cells in everything that goes with single battery) and it´s very good. Old laptop-harvested 2100mAh Samsungs goes into my lights, Convoys S2 and M1. Those veteran batteries are good enough, since current doesn´t need to go very high and capacity still seems to be 2100mAh… …ish, at least. 
There are unprotected and protected versions of both cells. Generally, the PF has lower internal resistance which means less voltage sag under load, single cell lights at 3A and above generally will stay brighter longer with the PF. They are also a bit cheaper.
There is? I stand corrected, thanks!
My light is going to be a little over 2A, do you think I would notice much of a performance difference? Obviously there will be a bit of difference between 2900mAh and 3400mAh. But other than that…
I don't think that there will be any noticeable difference in lumens at 2A. The 3400 B will run a little bit longer.
Thanks for all the info everyone. I ended up debating too long on what i wanted to buy and by the time i went to go grab a few of the Panasonic PFs this morning from RMM someone(s) had snatched up the last ones he had in stock. I ended up picking up some Orbtronic 3100 mAh protected cells. I think as soon as RMM gets some more of the PFs in stock i may pick up a few, along with some of the 3400 mAh ones (also sadly, out of stock). ill probably go ahead and pick up a cheap charger for keeping in my bag for when i am at work…
heh heh, seeing as i am already getting the Convoy S2 from you it would have been easiest if I had just thought about asking the battery question before ordering the light (and before the ones i was interested in were all sold out.) but that would require my brain to work sensibly.
More on the way, should be here early next week. Stay posted for updates.
awesome. any luck that the AR lenses might be in around the same time?
With any luck (if the cold weather and flight cancellations / delays don't throw a wrench in the works) they will be. <-- Yet another example of my extreme overuse of parentheticals! 
I haven’t really seen anyone disassemble the S2, is there a screw off bezel to get to the lens or is it more involved than that? do i need to take apart the head and stuff to get to it?
Just remove the head and unthread the pill assembly.
does it take any special tool to get the pill out? sorry, im new to all this stuff.