My 7Ahr SLA battery weighs 5.85 lbs. Being a clydesdale, that is only 2.4375% of my body weight (lets not talk about the stuff in the panniers!). I have been running by 25w halogen floodlight (from Home Depot), rear amber strobe, and rear beehive LED taillight full time both commutes (about 3 hours total) with probably at least one more commute time to spare. I know it seems like a lot of weight, but is nice knowing I don't have to worry about running out of juice. I just ordered (for two other bikes-my 2nd backup commuter and my son's new bike) a couple of 5 Ahr SLA from zbattery at 4 lbs each. Going to try the seat bag route to store the battery to streamline the build this time.