I got an F13 from GB in May,still XM-L then.$9.99 and it came with lanyard,18650 spacer and triple AAA battery carrier.See photo 3 in the customer photos.3 AA cells will not fit in any 26650 battery tube AFAIK so that is about 700-1000 mAh :~
Your other option is to use a smaller 17mm or 20mm driver. You can either use a contact PCB (like these 21mm ones from IOS?) as bibihang suggested or you can just strip the stock driver and use that in lieu of a contact board. IIRC there is enough space for any 17mm driver you want.
Thanks for all the great information guys.
I had wondered what those contact boards were used for. My soldering skills are not up to making my own driver, but that contact board idea looks doable. Thanks.
I think I’m about to acquire my first 26650 light.
I loaded up on them for $10, but for $9, may have to buy a couple more . These fit the 40mm NiteCore filters well (at fasttech) or this cheap one: fasttech-diffuser, as other common 40mm lights, such as the SupFire L5, SolarStorm/FandyFire K2.
Seems like a decent plan! You’re thinking of installing a 35mm triple? You’ll need a spacer of course. The stock flashlight uses a glass 37mm lens, so you may be forced to butt the triple optic up against the glass lens so it doesn’t fall out. I’ve been thinking about trying a triple with one of these myself. I can’t think of any build threads for F13 triples, but it should be similar to DBCstm’s Eagle Eye X6 triple builds.
Note that these should be the latest version of the F13 (same as the previous group buy on the same units from GearBest), they do not have a separate pill. I don’t necessarily agree with freeme’s conclusions, but the pics and information are all accurate and worth your time: freeme - UltraFire F13 mod issue ~ mini review included
EDIT: I have just measured the lens opening on an Ultrafire F13 from the previous Gear Best group buy. I got 33.8mm; IMO that should be plenty to keep the 35mm optic from falling out without leaving the glass in place.