Arduino Micro on 9V Battery Not working correctly

[lexical43]

When on 9V battery my project isn't working correctly. It works great on USB.

Here is the setup:

AdaFruit 10DOF board and an SD card. The script records the data from the 10DOF and writes to the SD card. This works great when on USB and connected to the computer. When I connect the hardware to the 9V battery (connected to VIN and GRN) the blue power light is on, the red led is on for the SD card. But no data file is created or if a file exists, no data is written to the file.

Tried pushing the reset button after hooking up the battery, Tx and Rx LED's cycle same as when connected to USB.

What am I doing wrong?

Thank you in advance for your help.

[Franklin97355]

Try a 9v power brick. 9v batteries do not have enough current to power your project for very long.

[lexical43]

Even if it is a brand new battery?
seems like it should work for a while on a new 9v.

[adafruit_support_bill]

I'd expect a fresh battery to run for a little bit at least. Do you see any signs that the processor is resetting by itself? Is there any output to the serial monitor reporting error/or success opening the file?

[lexical43]

No sign (that I know of) the processor is resetting.

I am not sure how to check the serial output when connected to battery. Doesn't the USB connection disconnect the battery connection on the Micro?

Thank you for your help.

[lexical43]

If I start the serial monitor with the device connected via USB with the battery connected, then disconnect the USB it appears to work fine. Disconnecting the battery and reconnecting the battery the device doesn't appear to loop through the code, even after hitting the reset button.

It appears the code on the Micro must be started using the serial monitor on the computer. Is this normal?

[adafruit_support_bill]

Post the code you are using. Does it reference the Serial port in setup?

[lexical43]

Eureka!

Commented out the call to begin a serial connection and it works great!

Thank you for your help.