There’s a review somewhere of a similar 7x or 9x XM-L2 torch and it does pump out a lot of lumens, but they had issues with the light dimming linearly with time, the batteries just can’t pump out that much current at anything other than full charge, i.e. it started at 3000 (measured) lumens, dropped to 2000 at half charge and 1000 towards the end. It wasn’t clear though if it was due to the voltage drop to 7.4 as they discharged or the battery’s chemistry limiting the maximum current draw (i.e. would they be back to full brightness if switched off for 10 minutes to let the batteries rest).
I was thinking of getting one of the 7x XM-L2 lights I linked to up there —–^ and running it from a 2s4p battery rather than the 2s2p or 2s3p they come with, to reduce the current drawn from each cell. Planing to semi-permenantly mount the lamp on the fork crown (rigid forks drilled for guards) and a magicshine rear light, then make a wiring loop for the bike all neatly ziptied with a connector next to the ST bottle cage to make removing/chargeing/fitting as simple as possible.
What we need is 8.4V dynamo’s!