After searching for 26650 cells I decide to make an adapter for my torch to use 18650. I bought them from Liion Wholesale. I tested them everything looked good. The double stack 26650 cell pack worked fine. I put my adapter sleeve in & as seen in my video the polarity is correct but the light came on when I know it was off. It cycled through the 5 modes & then I smelled something burning. After some research I believe what burned up were 3 transistors (which I can’t read the #’s & there is no markings on the board with “Q” or “D”) Any ideas what could have happened? I checked the voltage with the original 26650 pack & it was 4.14v in series & the 2 - 186650 measured 7.2v. The seller said any 26650’s can be used or it can be used with 2 - 18650’s. File sharing and storage made simple 
There must of been one dummy cell in the original pack for it to only be 4.14v —- Sounds like you ran too much voltage through your light
Thanks for the reply. It’s been bugging me & I would like to inform others if this is the case including Amazon as it’s fraudulent & dangerous. I just tried the 18650’s in my Bolder LC90 to do a comparison video & they seemed to work properly. In my video here you can see the voltages on the Sanyo after cycling & EBL 26650 (Which I’m testing now) but straight out of the pack the EBL’s had very similar voltage. Why did Flashlight Burn Up (Double Stack Voltage Tested against 2 - 18650 & 26650 Single Cells) - YouTube
Do you know how I could go about changing the circuit to use 2 - 26650?
Oh right, so i guess it should have a 2 cell battery pack that looks like 2 cells in series but is actually wired in parallel under a shrink wrap?
And that can be easily and safely be charged via USB, unlike 2 cells in series without balance charging.
So the OP butchered the driver with twice the voltage…
One of those FETs looks definitely smoked, and the other two are probably toast as well…
But who know what else got fried…
All 3 are fried.
I’m sure they are…
They had the job of dissipating the excess voltage, which was like 4 volts higher than intended because of the 2S batt. config…
So the seller was wrong about 2× 18650 or he meant make a similar parallel pack with 2x 18650 in stead of 26650.
Here is the message I received from the seller before I even bought the light. Seems pretty straight forward he’s recommending 2 - 26650 & 2 - 18650 would be the same voltage. Only difference would be battery diameter & these light use to come with 2 - adapter sleeves for 2 - 18650’s.
After searching YT for this light just marketed under a different name here is one: XANES 1282 XHP70 Flashlight - Unboxing & Outdoor Test - YouTube that is showing it used with 2 single 26650’s that comes with adapter sleeves to use 2 - 18650 (Basically what I made here: 26650 Adapter to 18650 Battery in Any Flashlight $3.89 - YouTube)
Only peripherally related, but I once ordered some D25 drop-ins offa Amazon. Labelled all over, on the webpage and an actual sticker on the pill, “3-18V” or somesuch.
Worked beautifully with 1 cell. Then I tried 2 18350s in series. Went dim and blue instantly and turned it off within 2sec.
Tried it again with 1 cell, seemed to still work fine.
Yeah, my review went from 5 stars down to 1 star after editing it. Specifically got that to be able to use multiple cells, and someone not cautious enough to be quick to pull the plug would’ve probably fried it after a few seconds.
Point being, don’t believe ads, or even physical labels, but be reeeeally careful.
I just got off the phone with Amazon & I hope they took & take my state serious. I took this double stack battery apart & indeed it is wired in “Parallel” & NOT “Series”. Others need to know this. As the first Amazon rep hung up on me. I recorded the complete call. Anyone interested can view my video here: WATCH This Before You Buy an (Amazon Flashlight) & NEVER Use 2 - 26650 (Part 1) - YouTube
When you saw the lumens claims and the claim that it’s a waterproof zoomy you should not have clicked on it. The Amazon lady is correct in that you should use the battery that came with the device. You thought you knew better and clearly you were wrong. There are quite a few things regarding flashlights that I try to avoid. Zumiez, more than one battery, any brand that makes outrageous lumen claims, any brand that I’ve never heard of, lights that are sold under different names,ect. That light pretty much ticks every single box that I would never ever purchase or use. I pretty much always test the voltage of any new battery of any type. Whether it’s a car battery or a detestable alkaline battery. Before I install it or use it I always test the voltage. I have apps on my phones so I can see my phone battery voltage. The good thing is you probably won’t make this battery mistake again. I don’t know if you’ve learned your lesson on Zumiez.
The original battery pack said 10,000 mAh and 3.7V, clearly indicating that this is a 2P pack, and you replaced it with a 2S pack instead, with double the voltage and half the capacity.
The result is actually exactly what was to be expected. Not sure this is on the seller or Amazon, tbh.
PS: Regarding the Sanyo 18650s: not sure if I see that correctly in your video, but independent whether you arrived at 3.58V after either charging or discharging 3,500 mAh, this seems off.
The thing is… this is your fault. Were I the seller, I would not feel compelled to do anything for you.
You had a good idea for the sleeve, just a very bad idea for this particular light.
Let’s face it, your error broke the light. I feel for you, but it is what it is.
Jeez guys what’s with the hate? Let’s not be the type of people that attract complaints about the other forum…
OP: Rasonably easy mistake to make, I don’t think I’ve EVER seen a light with that format before.
Yes, I agree the message from the seller is not clear.
Generally I tend to avoid those kind of lights as alternatives with better cells/led/build quality are available.
You might be able to find a replacement driver, tricky with the charging port and blinky LEDs though.
No hate from me. I feel bad for him. I have made such mistakes and, unfortunately, broke things costing much more than this light.
This made me very unhappy!
Thing is, when you make this kind of mistake, it is just wrong to blame it on someone else and expect them to make you whole.
The message from the seller was not clear, but neither was the question. 2 cells, is 2 cells. Configuration is critical… Obviously.
The seller obviously does not know much about what he sells, you can blame him for that, but OP knew the original pack is 4,14v and series wiring doubles volts. so i'm not sure who is more at fault, i'd say 50/50
I opened this only because it said fried trannies.
Is any interesting, but slightly misleading title.
LOL, Me too, first i thought.. no... no way,, then i thought may be it is about dead car's transmission, it is called tranny in shop slang. but turns out it is neither..
@Super Prinz Here are the pics you requested along with the so call manual that came with the replacement light today. The picture of the bottom of the board is just the LEDS to show charge.
Board:
Manual: