Also to know is, how often do you have to change the batteries in active pickups?
To give you a basic idea, you should get anywhere from 1000 – 4000 hours of battery life in a guitar with active pickups. Rechargeable 9V batteries can be handy if you use active pickups as well as guitar pedals.
Subsequently, question is, do active pickups work without a battery? Yes, active pickups need 9V batteries to work. Active pickups have an inbuilt preamp, which requires power to run. If you try to use active pickups without a battery, you won't get any signal at all.
Also question is, why does my guitar have a battery in it?
If the guitar requires a battery of any kind, it means that there are either active pickups (which have electronics built-in) or that there is some other piece of electronics inside the guitar control cavity or somewhere else. say a preamp or gain boost circuit.
Do electric guitars use batteries?
Active pickups and piezo-electric pickups will require batteries, while passive will have no need for additional voltage source. In most cases, for regular and low-end guitars, there will be no need for batteries. Originally, electric guitars had no need for additional voltage sources of any kind.