Ahh… yeah I see how that would be the stall voltage… never heard that term before but makes complete sense…
Really no idea, since this was a track powered loco originally, running up to 24v and now on 9 or less…
Yes, the voltage drops a bit, but very dependent on battery chemistry… your alkaline cells hold a bit over 1.5 until pretty close to death… nicads have a pretty sharp decline too… i.e. hold most of their voltage until they get very close to “out”… nimih has a more constant decline…
Incandescent bulbs are VERY sensitive to voltage, and humans can detect even a minor drop in voltage…
Actually the other way around less push (voltage is more analogous to pressure)… but light bulbs are weird animals since their resistance is very dependent on temperature. Current is more analogous to gallons per hour in a hose, if you use the water analogy, voltage is pressure.
It will be interesting how this little loco pans out… If I got one, I would most likely put a prismatic LiIon in that battery space and get more capacity (amp hours)…
Greg