I'm thinking of getting a new active mid booster for my Charvel 650xl. When I got it I took out the mid boost because it wasn't working well. From what I've found from google searchs the fender and emg mid boosters seem to be the most popular, but I haven't been able to find anything about the battery life of either one. Does anyone know how long the batteries last for either of these? Id aslo like to hear about anyone's opinions of these or other onboard mid boosters.