https://www.baldengineer.com/tag/datasheetRecent content in Datasheet on Bald EngineerHugoen-USTue, 24 Mar 2015 22:40:22 +0000https://www.baldengineer.com/9v-batteries-suck.htmlFri, 14 Feb 2014 12:00:37 +0000https://www.baldengineer.com/?p=2296Smoke detectors beep when their backup battery dies, which always seems to occur in the middle of the night (at least for me.) These backup batteries are usually a small rectangular 9V. They have become popular choices for electronics projects. If you need your Arduino project to last longer than a day, this isn’t the battery you want to use. Here’s why. What is a 9V Battery The 9v battery comes in a standard package about 25mm wide, 16mm tall, and 47mm long. On top there are standard snap-style connectors. The design of these connectors prevents you from attaching the battery backwards.