Trying to figure out which protected 14500 cells will fit this light. I tried a Thorfire 750 mAh (I know… but it was cheap) and it was a no go.
Anyone know which cells will fit?
Thanks
Keeppower 800mAh fit
You need a protected as the driver trips the PCB
Olight 14500 should be quite safe too.
I have used in MK I: Fenix 14500, Nitecore 14500, Klarus 14500 and Olight 14500. All protected.
The only that not fit in my MK I is one JL-148 14500 (Jetbeam 14500)
Trustfire Flames also fit.
Fail 
I’m running a KeepPower 14500 840mAh protected in mine — works great.
Yes …. curious circumstance …. 
Keeppower 840mAh is the best deal.
It has the much loved Sanyo 14500 under the wrapper.
Thanks for the info gentlemen, I appreciate it. Think I’ll try a couple of the Keeppower 840 mAh’s for now.
Check your battery, no way jetbeam will make a light wont fit thier battery
All 4 my jetbeam fit very well with jl148
My jl148 go fine with other that accept long batteries like my Solarstorm SC01 flashlight.
But, is to long for my MK-1
Regards
looklike the positive contact of your battery is quite……different from me
you can clearly see the pcb board
https://www.google.com.vn/search?q=jetbeam+jl148&espv=2&source=lnms&tbm=isch&sa=X&ved=0ahUKEwi_tpX9nIzRAhWBMpQKHagKBm0Q_AUICSgC&biw=1920&bih=925#imgrc=\_icrtCpFW6qlfM%3A
and yours is different from this, too, IMO
My battery is exactly like this ( the pic is from batteryjunction)
(there are a big tolerance in sizes of 14500 of the same brand. I see this in Nitecore 14500, Olight 14500…)
well, then you got unlucky, i guess, i have 2 jl148, and both fit well
Sanyo 14500 protected fits fine. I got mine from Mountain Electronics.
Nitecore 14500 fits!
KeepPower 800 mAh almost fits, it’s hard to pull it out. However I removed silver sticker and cleaned up a glue. Now it’s a perfect fit 
sanyo unprotected work fine
What does the light do when it’s below 3 Volts?