One 18650 battery does not have enough capacity to run an XML-led at 820 lumen for 2,5 hour, even the best 18650 will last for less than one hour.
Be carefull with high-power lights with a drop in module, because most of them do not have a good thermal contact between the drop in and the flashlight body. If you want to use it on your bike on High mode, it is possible that the led will overheat (i had the same problem with a XPG-R5 drop in flashlight, the led just fell off the star).
the lumens may not up to the standard you want it to be. and the site there says: While using 16340 such kinds of rechargeable lithium battery, you should avoid over-charge and over-discharge.
If you are a budgeter, try this one, because it carries with the bike count if you think so.