I have an Ibanez Ergodyne EDA900 active bass, and the batteries only last around 10 hours before they start losing voltage. I haven't actually tested the dying battery with a meter for voltage, but it begins to sound distorted and muffled, and changing to a fresh battery solves to issue. The 900 has a big enough compartment to hold two 9Vs. I am really asking if I can run 2 9Vs in parallel to double up the amperage available. Has anyone done this? Also, I am making the switch to rechargable batteries since the band has so many things that require 9Vs. There is a new 10 battery charger than charges these 9.6V batteries. The higher voltage might just fix my battery issue, and running two of them will make it last a good anount of time. Any thoughts?