Here’s a "Who Would Have Thought Of That?" tech tip from Sweetwater’s ever-vigilant Repair Technicians:
Be careful when using new batteries which feature a "self-test" strip on the side! While self-testing can be a great way to tell if the battery is fresh, the strip can potentially make contact with a device’s metal casing, causing problems. Example: We’ve seen Kurzweil K2000’s where the batteries were installed so that 2 of the 3 replacement batteries were continually self-testing themselves, and drained out overnight!!