Berkeley, CA based Keith McMillen Instruments has come up with a handy little device called the Batt-O-Meter ($29.99). Essentially a battery tester for musicians, the Batt-O-Meter plugs in to any guitar pedal or electric instrument with a 1/4″ jack, and displays the remaining life and voltage delivered from the battery. While it can also test standalone 9V, 3V, and 1.5V batteries, the real advantage of this product is that you can check how much life is left in your guitars and pedals without having to remove the batteries. Simply plug it into your favorite guitar pedal, hold the test button, and the display screen will tell you the number of volts provided by the battery, and the number of hours remaining until it runs out of juice. There’s a selector on the side of the device with three different battery chemistry settings (Alkaline, Rechargeable, and Carbon Zinc). Make sure you know which type you are using, because you can get some funky results if you choose wrong. The Batt-O-Meter calculates the hours of life remaining by comparing the voltage load of your pedal to the amount of energy in the battery, so changing your pedal’s settings will alter your results. […]... Click on the title for more