It depends on how much Lux you want to get out of the lantern versus runtime using the 18500. Some of my lanterns i use for longer camping trips, so i need a good balance of run time & output.
i used a Nanjg 105c driver, but the Q-lite Rev. version connecting the fourth star to get 4-modes, High, Medium, Low, and Moonlight for a night light.
One lantern i used this driver with five of the 7135’s removed, leaving three 7135 regulators for a roughly 1 amp high mode through a warm White tint XM-L2 mounted on an old heat-sink from a North-bridge chip off an old computer motherboard for cooling.
Low mode gave the same amount of light output (roughly 100 lumens) as the stock 20- 5mm leds did in the lantern, but with a run time of 30 hours on 3-AA cells, and twice that on an 18650. on medium it was roughly 235 lumens, with a run time of 8 hours or more on the 3 AA eneloops, on high it was atleast 450 lumens with a run time of just under 3 hours.
One example, is the side light on the OL’s 2nd hand-built Competition Steam-Pipe light i built.
The side light runs off the same Qlight Rev. 105C with the 4-modes, and uses a warm white wide-angle generic Bead type emitter with a resistor in the cirsuit after the driver. Its as bright on high as a Coleman Peak-1 Gas lantern i have, and has a run time of 35 plus hours on a single IMR18650.
Here: >> DBSAR - The 2nd. Annual BLF Scratch Made Light Contest Entry / UPDATE -June 27th, more photos ( scroll down through the photos to see the lantern_mode operating along side the Gas Lantern. )
Maybe i should to a photo of my LED lantern collection to snow some of the modded lanterns in that collection. 