Fender Deluxe Active Jazz Bass® V

Yes, one volume knob.

 

I find the battery lasts a solid year. Provided you unplug the bass when not at the gig and it's being unplayed. Most 9V alkaline batteries are about 9.4-9.6 volts when new, after a year of about 125-150 hours use, it's reading just under 9 volts. Once they drop below 8 volts, they can start to sound anemic and distorted.
I once left a battery in my Dlx Jazz V for 4 years when I wasn't playing it as often. The battery still read 8.2 volts.

 

"battery life."
they last a long time. a year, plus.

this guy will plug into your guitar! and tell you how many volts your batt has, and, how many hours of life that works out to. super handy.

Keith McMillen Instruments Batt-O-Meter - Test Batteries in your Bass or Pedal!