@atypicalguy, that's a perfectly healthy approach to power data, and honestly the most sensible one. Relative consistency matters far more than absolute accuracy when you're using the same bike on the same climbs. If your number says 170W today and said 170W last Tuesday, you know where you stand regardless of whether the real figure is 170W or 140W or 200W.
The battery management question is the real tactical challenge with your setup though. Running out three miles above Palisades with steep climbs still ahead and a 50lb bike with no assist is… character building, to put it mildly. The fact that you're exhausting the extender before topping out of your canyon suggests you're front-loading the hard effort onto the smaller battery, which makes sense given the gradient, but it does leave you exposed on the back end. Worth experimenting with dropping to one bar of assist on the steepest sections and letting your legs take more of the load early, saving that extender juice for the rolling sections later where the motor's efficiency is actually better. Counterintuitive, but steep low-speed grinding is where these small motors are least efficient per watt-hour.
Your point about gearing is well taken too. A 50lb bike with a dead battery on a steep climb is basically a cargo bike without the cargo. If you're running a standard 10-51 cassette, that 51t bailout gear becomes genuinely critical in that scenario. Some Fuel EXe owners have switched to oval chainrings to smooth out the low-cadence torque delivery when the battery's gone, which might be worth a look given how regularly you're riding to empty. Three bikes in the family all doing the same routes means you've got a surprisingly good data set building up, especially with your son's alien aerobic capacity as a control variable.
