The 8.2 (or 8.3) Battery Voltage Bug

[Mark McLeod]

Originally Posted by Al Skierkiewicz

Gene and Mark,
Does the OI report normal battery when not running the code? This is very interesting since the RC is on the hairy edge of reset at 8.2 due to the dropout restrictions of the internal regulator. Are you running the IFI backup battery charger circuit as well? When you measure the main battery are you at the battery or at the RC terminals?

All this is by my recollection, not directly from my test notes which are in our Robotics lab, so I may have forgotten some details.

Were not able to comparison test using the default IFI code or other variations. Ours was based on Kevin's streamlined camera code. We were running a mixture of drive train only and shooter/gimbal.

Normal battery voltage ups and downs were displayed on the OI until it suddenly went to an exact display of 8.2v.

We ran with the backup battery trickle charger circuit and charged backup battery. We did disconnected it for one of the tests, but we were looking at the sporadic controls problem and I don't remember if the 8.2v symptom also occurred when it failed. All while drivers and mechanics were simultaneously working out their problems of course. No servos or other drains on the backup battery, we even moved the camera-only power to an analog pin.

Measured main battery voltage at the battery was in the 11 to 12 volt range at the time under a light load (disabled). Under stress and very long running time the battery voltage was being driven down to 6 volts and the RC was transitioning to the backup battery fine.