In the 410, 412, and 414, the battery is a CR2032 coin cell battery. The 412DMX battery is a CR1632 coin cell battery. The battery in the Series 4 JNIORs is replaceable. The battery in the Series 3 JNIORs was not replaceable. The batteries have a life of around 6 or so years. This can vary and is impacted most by the amount of time that the unit is without external power.
What does the Battery do for the JNIOR?
The battery is needed to maintain the SRAM and the clock. The SRAM holds the root of the filesystem. Most notably, log files. Log files are useful for debugging an issue and can be frustrating if they keep getting reset. The battery is only needed in the event that the JNIOR loses external power.
What happens when the Battery dies?
The unit will operate correctly in the event that the battery dies. The issue with a dead battery is only noticed if the JNIOR loses external power. If the battery dies and external power is lost then the RAM will be reset. You will see the following message on the next boot. “SRAM was reformatted on boot”. The clock will also be reset to January 1, 1970 0:00 UTC. The clock will be fixed if the JNIOR has access to a NTP server.
How do I know if the Battery is good or bad?
The battery voltage can be measured with a voltmeter. The voltage of a good battery should be 2.7 volts or greater.