Does anyone make something like the Keith McMillen Batt-O-Meter that operates at 18V? I've got a Jazz bass with EMG JVX pickups and an EMG BTC preamp with an 18V supply, and I'd like to be able to test the batteries. I tend to be overly cautious and throw them out earlier than necessary. It's wasteful and expensive, and I'd like to curtail that. I suppose I could just use my ears, but... A meter has nice shiny lights!