I was mostly be a smarty pants... but....
I am focusing on lighting that I can run at low weight for 90 hours.
Best I can get is 104 hours on my rear without battery change; and 43hour on my front, so I would have to carry 1 spare battery currently to get those hours.
So Qty 3 5600mAh batteries would do it; not sure how the weight compares but I bet it's probably 25% more. My targets have support vehicles which gives me more freedom though. There are now 6200mAh batteries that are the same weight. 250g per battery. I'm night blind which complicates things if I tried to ride on 120 lumens, I'd hit every pot hole. The 113/412 lumen pulse mode makes a big difference for me.
Very,very smart to wait on lights. This industry is getting better and better. I suspect in a couple years they will have advanced to the point battery life and placing good light only on the spots it's needed will be achieved . Hopefully, even at a decent price.
No kidding I have a solar charing battery that cost $19 for 7200ma imagine what we'd have in 3 years.
Any how at the price on for Serfas I'm looking forward to more reviews. The Cygolite are similar but without that excellent changeable battery.