simple as hell, question the battery on the inside of themy guitar.. how the hell do i remove it?? because its gonna need changeing some time and i aint taking the strings off
if there is no compartment for you to open then you can try and detune the strings a lot and then push them out of the way.
The Gear:

Custom Strat
Mesa Boogie Stiletto Ace
Fulltone OCD
Electro Harmonix Small Clone Chorus
Dunlop Crybaby Classic
MXR EVH-117 Flanger
Fulltone Soul Bender
Are you sure theres no compartment on to change the battery? Can you post a picture of the external part of the pickup (where you should be able to adjust frequencies and that..) and also whereever it was that you were referring to in another one of your threads, where theres an arrow or something.

Plus, You NEED to change strings. If anyone tells you that they havent changed their strings in a year and it sounds great they are full of **** and if they actually did change their strings they would be thinking,wow, the old strings really did sound like crap like so many people told me.
Strings are VITAL on an acoustic. As soon as oyu take them out of the packet they will start deteriorating and, depending on how much you play, they will need changing at the very least every 2 months, if you have something like Elixirs or D'Addario EXP's.
With moderate playing, every 2-3 weeks is ideal, with heavy playing, well, 1-2 weeks, depedning on your strings, but thats a general guide for ALL strings.

So you WILL need to change your strings at some time, and then you can change the battery if you actually have to change the battery. Oh, and providing you unplug the guitar when your not playing, the battery should last a while (If you leave it plugged in it will drain the battery, same as with most pedals)