Although if someone wanted to do linear regulation, using 32 7135's is not the only way. There are beefier tools:
page 3 here for application:
Looks pretty simple to me, but I'm no expert. Can they be stacked? I'm probably just showing more what I don't know than telling anyone anything. That's ok.
If you are talking for a bike light, best bet is to see what others are using. If you are talking about this light, then the driver is already set. I plan to make an aftermarket driver or 2 for it but they will be aftermarket.
I’m not sure what that easy design would be. I can not figure how a 4p set-up can easily be converted to 2s2p or 4s. The tail side is easy, but how do you do the head side of the battery compartment without a major overhaul?
Well.. if we want to discuss seriously making a bike light version then yes, it better be setup with drivers for 2s packs with magicshine connectors because that's what other bike light people do. It is being built with a tripod bolt already so in that since this really does make sense.
But if we're talking about what I should do to mod some random light (like this one) that isn't already a bike light, then who cares? There's nothing special about what bike people do to drive lights that is somehow suitable for biking. I've got some 4s packs and if there's an easy way to use those, fine. I don't care about software on my bike light anyway actually. I just want current to flow when I turn it on, at about 20 to 25 watts preferably.
It would need a new driver, which I am working on in the Texas Avenger thread. Basically just going to copy the Q8 driver but design it for 4s or 2s2p.
I think djozz was talking about how to convert the batteries to 4s. That would require changing the batterry connections on the head. I would guess it's not a hard mod, but it's a mod. Maybe you could run the lights 4s and keep the batteries 4p? Youd need a boost converter that can handle a big current input. For me it's easy to consider because I'm considering a remote pack.
Ok….if this has been asked then please forgive the repeat, but I can’t seem to find it.
With this light, how much real world difference in simplest terms will it make to use HIGH DRAIN cells vs a good ole Panny NCR18650B or Orbtronic protected?
I don’t expect a detailed analysis unless somebody is just in the mood. 
EDIT: I guess I should have asked, do we know cell length tolerance yet? Will protected even fit? Only asking because I’m trying to figure out if I’m gonna have to order a new supply or use what I’ve got.
Shoot, I could do some battery comparative testing on my 4X SRK proto, but should map the same as any single cell, single LED DD FET lights. I got plenty of all sorts of cells. Figure we will get about 4.0A-4.5A per LED per cell max on a 30Q or SONY VTC6, and a protected cell would probably drop that max down to ~3.4A-3.8A per LED per cell, roughly/best guess/etc. Of course a 20% drop in amps does not correlate to 20% drop in output - it would be a smaller drop in output.
I love using SANYO GA (unprotected) cells in my EDC 18650 DD FET lights - my eyes can't notice the difference, but I can measure it. Protected cells, of course are worse performers, depending on the quality of the protection circuit.
All correct
The tail PCB as shown at the top of this page is just adding some silk text and tracing to allow that part of a 4P to 2S2P mod be done easier
I can’t wait to see what TA is going to diptrace for this part
And after the not so good news of Thorfire not getting the driver (though no email received after emailing the manual and promptly getting a reply saying thanks and to now Chinese holiday don’t expect an answer before Monday 
) it is a great joy seeing BLF going foreard and still make the project progress, yeah! I needed that do thanks a lot for all this new input!
First…thanks for bringing it down a level for me! As a semi-newb, I ’preciate it.
I’m still learning a LOT of the terms that get thrown around here and what they mean to the end user……
So…to summarize….
Any of those statements need correction?
AND, the LVP in this light….I assume it some recognizes low voltage regardless of how many cells are being used. Yes or no?
Sure with protected good cells it will run in turbo but produce a little less lumens. Remember 500-1000 lumens you notice a lot, 5000-500 is much much harder to see.
Since temp is an issue on turbo anyway personally I like the versatility of lights like this and longer runtimes. So I plan on using one with trusty Panasonic protected 3400mAh cells.
No, think you got it down pretty good. I typically prefer the SANYO GA cells because they are the best 3500 mAh (highest capacity) around, and perform well, not as great as the 3000 mAh top IMR cells. LVP in Narsil is pretty advanced now - I rung it out good couple weeks ago so am pretty confident in it, and it alerts you to what's goin on. Might fiddle with the critical threshold though - I'm using 2.6V for critical level, and 3.0V for droppage/alerting. I believe ToyKeeper mentioned from testing, many protected cells can't even get as low as 2.6V - they with shut down before reaching that low, so a higher value of 2.8V or so may be better all around.
Button top unprotected are the best cell to use for this light. Many want to use protected - really defeats the purpose, but better safety. Just please don't use cheap protected cells - lot of garbage out there. Not all NCR18650B cells have quality protection circuitry, therefore the entire cell is garbage. One over discharge can kill it, or the protection doesn't kick in, etc. Buyer beware, as usual.
Thanks Tom, will keep an eye out for a set of those Sanyos for one of my Q8s!
And well with Narsil I could very well remove the whole protection part of 4 Panasonics when assigning them to a Q8 now can I
2,6V is wat above 2 so trust I you!
Which I have FOUR of….already….at no extra cost.
Probably going to go like this if I get this light…
Start off using the Panny’s, be in awe of it being the most ridiculous light I’ve owned.
Try it with varying cell quantities just for fun….see how it changes performance.
Start wondering……what IF……
Buy a pack of 4 30Q’s on some BLF special that I’m sure will get posted when I have the least money.
Hahaha big smile here
Happen to have a link for said Sanyo cells…I did some quick searching and found protected button top and unprotected flat top….but not the combo you referred to of button top unprotected.
Of course, at what appears to be $8-$10 per cell….if I get this light, it’ll probably have to be happy with the Panasonics I already have for a while.
Just add them to your favorites on for example Gearbest and one day they are flash deal a d affordable, that is what I am gone do.
Appreciate the feedback…but I was more meaning, I couldn’t find what he was referring to. Not necessarily a deal….but I couldn’t find the BUTTON TOP in a NON-PROTECTED (caps for emphasis in easier reading, NOT YELLING).
BUT….i think i see them now.
What about these?
https://www.fasttech.com/product/2399401-authentic-sanyo-ncr18650ga-3-6v-3500mah
Seems like a good deal…I’ve ordered from Fasttech before (just some TIR lenses)…took a looooong time to get here.
Can we trust them for “authentic”? I guess one other concern would be, most of the sites I’m seeing say Panasonic/Sanyo (since Panny bought out Sanyo)……would these be old cells or should we just assume not updated website?
SANYO GA 3500 BT Unprot:
http://www.mtnelectronics.com/index.php?route=product/product&path=59_88&product_id=352
The FastTech ones are flat tops. For me, I'd take the risk and solder blob the tops, but that's me - at your own risk...