Backup battery only lasts 10 seconds?

[dawilliams]

Our KOP 7.2V backup battery only lasts 10 seconds if we remove power from 12V main power suplly to RC. Is this normal or is something wrong? We ahev charged 7.2V battery twice. It measures ~8.4V static, and 8.2V under load of RC, but RC still shuts off if only backup battery is available.

[JamesBrown]

Originally Posted by dawilliams

Our KOP 7.2V backup battery only lasts 10 seconds if we remove power from 12V main power suplly to RC. Is this normal or is something wrong? We ahev charged 7.2V battery twice. It measures ~8.4V static, and 8.2V under load of RC, but RC still shuts off if only backup battery is available.

Thats perfectly normal. THe backup battery doesnt power the RC, you need to use it in combination with the 12v battery

[esquared]

The battery backup is intended to provide short-term power to the RC during voltage sags such as heavy motor draw, much like your computer's power supply does. Typical AC power supplies can "ride through" 1-2 cycles of missing input voltage without losing output regulation.

[Alan Anderson]

The master code in the RC shuts down the system after about ten seconds with no main power. That's intentional; otherwise it would run down the backup battery trying to keep the processor and radio running after the main breaker was opened. The constant power draw by the camera and its associated servos makes it important to turn things off quickly.

The 2004 RC kept running on backup power for a very long time. To shut it down quickly required pressing the RESET button. We would occasionally "jump-start" the system by accident by pushing it and generating enough power through the motors to bring up the processor. I once managed to do it intentionally, and then load a new version of the program, with no main battery installed at all.