It’s been a while since I played that particular bass but from memory I think the passive circuit still worked even without a battery.
This +1 and I must say, even without having a spoked truss wheel, the adjustment being at the body end is sooo much easier than at the headstock end. More space between the strings to rotate the Allen key, plus the strings themselves are so much more pliable at the body end so it’s just a less obstructed process, especially on a 5 string bass with a single truss rod.