Does battery in an acoustic guitar run out just for being in a guitar or does it have to be plugged in?
All batteries will discharge (slightly) regardless if it's in a circuit (pick up) or not. Also, they can erode too if it's not keep in the proper environment.

Nothing you can do to change the physics of the device. The discharge rate is also dependent on the type battery too. Just some extra knowledge .
Hydroxic acid, kills thousands of people every year. Studies have shown lakes and rivers all over North America contain high levels hydroxic acid. Currently governments have taken no action against this life threatening chemical.
Last edited by |Long| at Aug 15, 2010,
The batteries will discharge over time, even when you don't plug in your guitar... and whatever you do, don't do what I did and forget all about the batteries in my electric acoustic... to find they eroded and leaked... just had to order a new battery pack/output jack combo for my Ibanez Electric Acoustic... eek!